Fiesers' Reagents for Organic Synthesis (Volume 21)

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Fiesers'

kagT 068x

for Reagents OrganicSynthesis

v.Jl

VOLUME TWENTY ONE

Tse-LokHo National Chiao Tung University Republicof China

@WTI.EYINTERSCIENCE A JOHNWILEY & SONS.INC..PUBLICATION

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retrievalsystem'or transmittedin any form No part of this publicationmay be reproduced.storedin a orbyanymeans,electronic,mechanical,photocopying'recording'scanning'orotherwise'exceptas Act, without either the prior perrnitted under Sections 107 or 108 of the 1976 United states copyright writtenpermissionofthePublisher,orauthorizationthoughpaymentoftheappropri?teper-copyfee totheCopyrightClearancecenter'Inc.,222RosewoodDrive,Danvers,MA0l923,978-750-8400' fax978-750-44.l0,oronthewebatwww.copyright.com.RequeststothePublisherforpermission Wiley & Sons' Inc'' I I I River Street' should be addressedto the PermissionsDepartment' John email: permreq@wiley'com' (201) 748-6008' Hoboken,NJ 07030,(201) 748-601l, fax and author have used their best efforts Limit of Liability/Disclarmer of Wananty: while the publisher with respectto the accuracyor w.uranties or no representations make they thisbook, in preparing completenessofthecontentsofthisbookandSpecificallydisclaimanyimpliedwarrantiesof may be createdor extendedby sales merchantability of fitnessfor a particular purpose' No warranty containedherein may not be strategies and advice representative;or written salesmaterials.The suitableforyoursituation.Youshouldconsultwithaprofessionalwhereappropriate.Neitherthe publishernorauthorshallbeliableforanylossofprofitoranyothercommercialdamages,including tut not limited to special, incidental' consequential'or other damages' pleasecontact our Customer Care For general information on our other products and services at 31'I-572-3993 orfax317-5'72-4002' u.s. the Dep"artmentwithin the u.S. ^18'77-762-2974,outside

Library of Congrcss Cataloging in Publication Data: ISBN 0-471-21393-4 I S S N0 2 7 1 - 6 1 6 X Printedin the United Statesof America' 10987654321

I

:,-€

{:ra:

ar

l

(o"" \.,\,,,\,/CHO

+

--Jo

t( w

Ff" tl. l

\ ri"t { r ^l

BuLr/ THF --;:*

B r \

-

i}e.::

Llrrr:r. ..*d.

\l r"

,

9 8 Y o( Z : E = 9 6 : 4 )

'Wung, El KhouryM., Schlosser, M. CEJ6,420(ZOOU. Q., Alumina. N'Alkylation,t been reported.

Gas-phasealkylation of amines with arcohols over "y-alumina has

oxidations. Dramatic improvement has been claimed in handling aluminasupported Mno2 for oxidation.2 Potassium ferrate deposited on alumina can be used to remove a terminal [CH2O] unit from propargylic alcohols.s

' t -

_ L : ,

rh

\

,rI. \l

: r

llrr

lil-r

[ t \

ff.r_-J__:f,&

rflu:".ict:r! \f

:r\(i

j (-:

!q--

clridtfl.F a.yu. Itz*f4 nln

fl:'',

-r

\l

T

:ia

ir"r

!r- :'u-J

\ 5

[nr-:

!.r: iarr

\l

i.1^--

ll trt nz :

Aluminum chloride

!:

,elkanolsis (--I bond).

15

Nonaqueousproceduresfor oxidation of mandelic estersaand the cleavageofp-nitrophenylhydrazonesand semicarbazonesinvolves treatmentwith ammonium chlorochromate adsorbedon alumina.s Valot,F.,Fache,F.,Jacquot, R., Spagnol, M., Lemaire,M.TL40,3689(1999). :stavrescu,R., Kimura,T., Fujita,M., Vinatoru,M., Ando,T. SC 29,1'r.19(lggg). 'Caddick,S.,Murtagh, L., Weaving, R. Zt 40,3655(1999). rZhang,G.-S.,Gong,H. SC29,3149(1999). 'Zhang, G.-S.,Gong,H.,Yang,D.-H.,Chen,M.-F.SC29, 1165(1999).

I

-,r(1999)

Aluminum. Reductions. Aluminum with NH4CI in methanol reducesnitroarenesto arylaminesr on ultrasound irradiation. on the other hand, Al-KoH induces hydrazoareneformation.2 Under similar conditions (Al-NaOH) reductive dimerization of araldehydesoccurs.3 concerning reductive dimerization in aqueous media, it is interesting to note that changingAI-KF to Al-FeF2 system causesreduction to ATCH2OH only.a Reduction of arenesby Al in ionic liquids is efficient. For example,pyrene is fully saturated(847oyield) and 9, lO-dimethylanthracenegives the 9, l0-dihydro derivative (8lvo).5 Aldehydes from nitroalkenes.6 By using Al-NiCl2.6H2O in THF, nitroalkenes are convertedinto aldehydes(9 examples,60-88Vo). Epoxide opening. Aluminum and an organomercury chloride mediate reaction of !'poxideswith acyl chloridesto furnish estersofchlorohydrins.T ^l

r(

Jcs affords r relds are

A Phl'

cl')rR o .

3

-

pr.rl-r-,.o-rr

R tl

o

-"'ove 9Hscl

96% \rgaraja, D., Pasha,M.A. TL 40,7855 (1999). Xhurana,J. M., Singh, S. JCS(PI) 1893(1999). Srhade.D.A., Kawaji, T., Sawada,T., Mataka, S., Thiemann,T., Tsukinoki, T., Tashiro,M. ./CRiS) :lr)(1999). l-r L.-H.. Chan,T.H. OL2, lI29 (2000). tJams, C.J.,Earle, M.J., Seddon,K.R. CC 1043(1999). 3czbarua,M.S., Bez, G., Barua, N.C. Ca 325 ,1999\. l - : z z r o .F . A . ,B o b b ,R . A . 2 5 5 , 1 8 5 1( 1 9 9 9 ) .

aas c: '.-.rluminh r..i.:ng aluminani ,.rn bc usedto

{fuminum chloride. 20, 12-13 Deprotection. Ethers are cleaved with AlClr-NaI without solvent.r Friedel-crafts reactions. Phenylsulfenylation is conveniently canied out using N-r"'nr lthiophthalimide.2 Acylation of benzodioxin derivativesrin the presenceof Alclj-)\1.'\ without solvent is regioselective.This complex behavessimilarly to Alcl3-DMSo .:J AlClI-DMF.

Aluminm

r!rr*

I,o--o,r

--+

r

4oAcooMrrcr3-DrvA

f

ll

(Y"l I

.f' ^oAcoor "

VoAcooMe

o (15 : 85) 97%

Formylation of ferrocene can be accomplished by reactlon with triethyl orthoformate in bromobenzeneat room temperature(92% yieldl.4 Somewhat lower yields are obtained in benzeneor dichloromethane. Reaction of areneswith phCCl, in an ionic liquid ( N-butylpyridinium chloroaluminate)givesdiaryl ketones.. Rea*angemenrs. Anl surfonatesundergo Fries-type rearrangement when exposed to .'\I6-1,-t na, - undc.rmicron.aveirradiation.6 -\ l.rmal o ->c migration of an oxymethyl group to afford spirocyclic productsTis rr'.rlrzedhr erposing dibenzodioxepinsto AlCl. Other Lewis acids are less efficrent.

IGhiaci, M., Asghari,J. SC 29. 9?.r , 2Suwa, S., Sakamoto,T., Kikugar:_, 'Suarez. A.C.TL40.3523 r ld9, aTang,J., Liu, X.-F., Zhang, L.-) . )t, )Rebeiro, G.L., Khadilkar, B.Il. SC J 6Moghaddam, F.M., Dakamin. It.G j TColeman, R.S., Guernon,J.M.. Roh oMa, S., Wei, e. EJOC 1939 (20m, 'Song, Y.-S.,yoo, 8.R., tre. G.-H . Jr roSudo, T., Asao, N., Gevorgyan.\.. )i " Lee, C.W TL 40, 2461 (199q ',xi,z.,Li,P. A C I E E 3 9 , 2 9 5 0( t m ,

Aluminum hexafluoroantimooe plactones.t Acidchlondc

o\ct R R

-{-l&R /:/

L-

o''''-*-A H cH2c'2 RR

\$-/--

b...-J-

R = Me

gSYo

Hydrosilylation.e''' Traditional methods of hydrosilylation involve the use of transitionmetal catalysts.However,Lewis acidssuch as Alclr also show such reactivity. Diels-Alder reactions.tt Addition of Alcrr to r-ethyl-3-methyrimidazolium chloride forms a chloroaluminate ionic liquid. This substance acceleratesand enhances the selectivityof Diels-Alder reactions. cyclopentadienes.t2 Replacement of the metar moiety of zirconacyclopentadienes that are readily available from alkynes by the [RCH] unit of an aldehyde is accomplished by an AICIr caralyzedreaction.

Aluminum tris(2,6-diphenylphco AAolreaction o,p_Unsaru condensation with phCHOat the11

t

l

\z\ l_

^,-\,/ r (

.ZrCp2 + \ R

R Atcl3

R'-CHO

K.

R l

ll >-R'

R--Y

R

-

-\-"--\rcHo

l R i

I H\-,

rNelson, S.G.,Wan, Z.,peelen,T.J.. Sp

2-chloroallyl sulfuxides.s Allenyl sulfoxides undergo addition of HCr in the presenceof AlCl.-HrO.

K

*

|

r

-\,.\-\ I cHo

a-Alkoxybutylation.2 A rela1.r of enolatesin THF-toluene mrxture. .

Aluminum tris(2,6-diphenylphenoxide)'ATPH

-_r) /'aAcoolt'tu

t7

rGhiaci, M., Asgharl,J. SC 29,973 (1999). 2Suwa,S., Sakamoto,T., Kikugawa,Y. CPB 47,980 (1999). 3Suarez,A.G. rL 40, 3523 (1999). aTang,J., Liu, X.-F., Zhang,L.-Y., Xu, X.-L., Zhang, P.-R.SC 30, 1657 (2000). sRebeiro, G.L., Khadilkar, B.M. SC 30, 1605 (2000). 6Moghaddam,F.M., Dakamin, M.G. TL 41,3479 (2000). TColeman,R.S., Guernon,J.M., Roland,J.T. OL2,271 (2000).

8Ma,s.,wei,Q.EJoc 1939(2ooo). eSong, LN.OM18,3109(1999). Y.-S.,Yoo, B.R.,Lee,G.-H.,Jung,

e:::. ,)(hoformate \:. .:- ,rrcobtained

IoSudo,T., Asao, N., Gevorgyan, V., Yamamoto,Y. JOC 64,2494 (1999). I rLee, C.W. TL 40,2461 (1999). t2x| 2., Li, P.ACIEE 39, 2950 (2ooo).

r. .. r. ehloroalumi1 ; ' ' . r h c ne x p o s e d s r . , . r i p r o d u c t siT .- -'tlicient.

Aluminum hexafluoroantimonate. plactones,l Acid chloridescondense to give B-lactones. with aldehydes

oY"'

+

O tt ,{

Al(SbF6)3 / i-Pr2NEt CHzClt 25i

-

H- \.,-\-.

Vo L-l

9rn

HN

93Yo I Nelson,S.G.,Wan, 2., Peelen,T.J.,Spencer,K.L. TL 40, 5635 ( 1999).

r HCI in the rr. .rc the use of p., ..r'h reactivity. -:::-t:r Iirnidazolium a:.::-'.irfldenhances

ATPH. 20,14-15 Aluminum tris(2,6-diphenylphenoxide), in the carbonylcompoundsshowregioselectivity Aldol reaction a,B-Unsaturated with PhCHOat the1-positionafterenolaluminationwith ATPH.I condensation

;^,*Til

-(---J=rcHo

^a-

63yo

. .lopentadienes o:r.1L\.:- :. llccomPlished

A-^-\

ATPH ;

84To LDA,PhCHO

cHo a-Alkoxybutylation.2 A relay attack of epoxides has been observed in the reaction of enolatesin THF-toluene mixture. The coordinatedTHF is involved.

IE

1-[c'(Amino)arylmethyl]benzotriazoles

Ammonium molybdate. a-Ketols.t Epoxides are co at room temperature(l I examplc

o

*Jl-/*' t ^ \r"-\.''""

LDA' THF

| R,\'--R'

orr" (^\1" V

oh t 4) \-Pt.

I Ismail.N.. Rao.R.N.CL 841rll-::r. Antimony.

o'

admixture of ATPH with Addition to aromatic nuclei,3 complexes formed upon fucoclaresusceptibletoattackbynucleophiles(e.g.,enolates,/-BuLi)atanucleal position.

" oo^"ffi)co^".od oH

cr

o'.r

v

15To

43Yo

.{l Homoallylic alcohok. mediatedby activated Sb-KF Li. L.-H.,Chan,T.H.rl 41.5ffic ': Antimony(V) fluoride. Carbonyl chloride fuoridc. rreatmentwith SbFs.

K.O.JFC9l, lrr' Hoge,B.,Christe,

A rcnediazonium o -benzeoedis Aryl halides,' Decomprxrt emmoniumhalide furnishesan I

rsaito. S., Shiozawa, M., Nagahara' T', Nakadai, M"Yamamoto' H' "/ACS 122'7841 (2000)' 2saito. S.,Yamazaki,S', Shiozawa,M., Yamamoto,H' Sf 581 (1999)' rSaito. S., Sone,T., Murase, M., Yamamoto, H' 'IACS 122' 10216 (2000)'

Aluminum tris(2,6-diphenylphenoxidelalkyllithium' are ^y-stannyl ketones2derivedfrom cycloalkenones Fragmentation 1-Iodor and areamphiphilic' ketones.The reagentcombinations convertedinto unsaturated

I '

ATPH / BuLi

-

PhMe - Et2O

a-'/ I

w

o 93% rKondo,Y., Kon-i, K., Ooi, T., Maruoka, K TL 40,9041(1999). K. ACIEE39,414(2000) rKondo,Y, Kon-i, K., Iwasaki' A., Ooi, T', Maruoka.

1-[ot-(Amino)arylmethyl]benzotriazoles with these feagents to Aminobenzylation of phenols,t Sodium phenolates react

Blrbero.M., Degani,1..Dugherr"S

{renesulfonic acids. .Vannich-typereaction. S j\c!-llent catalystsfor the con&o

4>'u.OMe * PhcHo + ll \z

NHz

furnish Mannich-tYPeProducts. IKatritzky,A.R.,Abdel-Fattah,A'A.A',Tlmoshenko'D'O''Belyakov'S'A''Ghivirigia'I'Steel'PJ' JOC 64,601r (1999).

\l:nabe. K.. Mori. Y. Kobava-shr. S

Arenesulfonicacids

Ammonium molybdate. a-Ketols,t Epoxides are converted to ketols by ammonium molybdate tetrahydrate at room temperature(l 1 examples,92-96Vo). rlsmail,N., Rao,R.N.CL844(2000). Antimony.

L

\TPH with l a nuclear

Homoallylic alcohols.t Allylation of carbonyl compounds in aquebus media is mediatedby activated Sb-KF. rLi, L.-H.,Chan,T.H.rt 41,5009(2000). Antimony(V) fluoride.

-.,

oH

\. \a\" tl 15o/o

Carbonyl chloride fluoride.t treatment with SbF5.

Phosgene exchanges one of its chlorine atoms on ffr'

fil

lHoge,B., Ch-riste, K.O.JFC 94,107(1999). Arenediazonium o-benzenedisullfonimides. Aryl halides.t Decomposition of these salts (1) in the presence of a quaternary ammonium halide furnishes aryl halides.

n , o ""dirr\

,.. .r,kcrrones t

_

N lt ArN,* -ls:--'.9) o- \b (1) Barbero, M., Degani,I., Dughera, S.,Fochi,R. JOC 64,3448(1999). Arenesulfonic acids. Mannich-type reaction,t Sulfonic acids bearinga long chain (e.g., dodecyl) act as !-\cellentcatalystsfor the condensationin water.

:r:--e reagentsto

l,.J. . .t e e P r . : . : : . r . 1S

\lenabe, K., Mori, Y., Kobayashi,S. Sf 1401(1999).

20

B-(2-lvido-2-propenyl)-1,3,2-dioxoborinane

Arylboronic acids. Glycosylation,l The glycosylationof unprotectedsugarscan be accomplished whentheyareactivatedby arylboronicacidssuchas L.

Z\X o l l l ott')t\

Barium permanganate.

H

Oxidation,t Solvenrthis reagentor MnOl.

'ry

rFirouzabadi, H., Karimi.B . Al

(1) Benzenesulfenyl chloridcN-Arylimidazoks.2 complex in the air.

Arylation of imidazoles is efficiently catalyzed by a copper

Cyclnpropane ring q regioselectivityof ring open

rOshima,K., Aoyama,Y. JACS121,2315(1999). 2Collman,J.P.,Zhong,M. OL 2, 1233(2000).

Il /\

Arylp-nit to theiraryl estersby thesereagents. aminoacidsareconverted Aryl esters.t Protected rPudhom, (1999). T. TL 40,5939 K.,Vilaivan, 2.3-Azetidinediones. with aminesgivespeptides. Pepti.des,t Reactionof theheterocycliccompounds

o\-.R' ^Jf,

tJ

ETOOC'

-oMe 'OM.

PhS PhS(

Graziano, M.L.,Iesce.\l.R . C

3-Benzenesulfenyl-2-(N "#np

N=N

R

Acetals.t l,3-Diols can be prore. cyclic acetalsis by catalytic hydrogenar is instigatedby the releasedpriman hrd

OH

OH

*

cHo

\r^o

N=Ni 70To rPowell,N.A.,Rychnovsky, S.D."/OC61.:Ol

lKatritzky, A. R.,Mehta,S.,He,H.-Y.,Cui,X. JOC 65,4364(2000). Benzyltriethylammonium

1 I/-Benzotriazol-1-yl mesylate. N-Mesylation.r Mesylation of an amine in the presence of hydroxyl groups is possible with this reagent.Primary amines are more reactive than secondaryamines.

tetrathiorml Disulfi.des. Alcohols are con\.enc catalyzed) and reaction with the reagc organic disulfides are cleaved by tlr r trappedby Michael acceptors.r

rKim,S.Y.,Sung,N.-D.,Choi,J.-K.,Kim, S.S.TL 40,117(1999).

(1 II-Benzotriazol-1 -ylmethyl)trimethylsilane. Homologation of carboxylic aci.ds.t A reaction sequence for the homologation starts from a reaction of BtCHrSiMe., with RCOCI. After O-triflation, treatment with either TsOH and then BuaNF (aliphatic series) or NaOMe then HCI (aromatic series) completes the transformation.

fol^ot v

lBnrEr.\i

rKatritzky,A. R., Zhang,S.,Fang,Y. OL 2, 3789(2000).

O - (Benzotriazol- 1-yl)- N,N,N',N' -tetramethyluronium tetrafl uoroborate. Ether cleavage.t This reagent catalyzes cleavage of THP, silyl, and 4,4'dimethoxytrityl ethers. rRamasamy, K.S.,Averett,D. SL709(1999).

Cleavage of propargyl carbamaratreatment with I equiv of the terarh irradiation.

rSrnha, S.,Ilankumaran, P.,Chandrasekaran S I Prabhu, K.R.,Sivanand, P.S.,Chandrasc\ar ' Sinha,S.,llankumaran, P.,Chandrasekara S

Benzyltrimethylammonium

Benzotriazol-1-yl alkyl carbonate. Amides.t Reaction with a carboxylic acid followed by aminolysis leads to amides. rl-ee,J.S.,Oh, Y.S.,Lim, J.K.,Yang,W.Y.,Kim, I.H., Lee,C.W.,Chung,Y.H.,Yoon,S.J.SC 29, 2547(1999\.

diphenltpt Stille coupling.t The title compc residues.On precipitatingRrSnop(O rF are facilitated.

Zhang,S.,Marshall,D., Liebeskind. L.S..rOC

Benzyltrimethylammonium

lf":

:

E: -' t-__'

I -benzotriazolyl)pyrrolidinones :rezole. and 2,5-dimethoxY-2,5i.r nucleophiles.

4-Benzyloxybutanal. Acetals,t 1,3-Diols can be protectedas substituted1,3-dioxanes.Cleavageof the cyclic acetalsis by catalytic hydrogenation in which an intramolecular exchangereaction is instigated by the releasedprimary hydroxyl group.

R

ol-ru\\Y R

I i l

diphenylphosphinate

aar'-r--

R'

3r or

*

9HO

\,,^orn

*r'Y*' H2 / Pd(OH)2-C

+

oLo,"

N=N

rPowell, N.A.,Rychnovsky, S.D."IOC64,2026(1999).

r :.. nrcsenceof hydroxyl groups t ' . . : . i r \ d t h a ns e c o n d a raym i n e s .

\: " .L'quencefor the homologation \ir!-r O-triflation, treatment with )r x \ :t )\tc. then HCI (aromatic series)

oni u m tetrafl uoroborate. . rj.rlc of THP, silyl, and 4,4'-

ll, Lr

: hr aminolysisleadsto amides. \\ . Chung,Y.H.,Yoon,S.J.SC 29,

Benzyltriethylammonium tetrathiomolybdate. Disulfides. Alcohols are converted to disulfides on activation with Dcc (cucl catalyzed) and reaction with the reagent (9 examples, 45-ggZo).t On the other hand, organic disulfides are cleaved by the title reagent and the resulting thiolates can be trappedby Michael acceptors.2

(Yo' v

CuCl,DCC

O.^t"'-O

lBn(Et)3Nl2MoSa

88%

cleavage of propargyr carbamates.3 The amino-protecting group is removetl on rreatment with l equiv of the tetrathiomolybdate salt in MeCN with urtrasound irradiation. p, Chandrasekaran, Sinha,S.,Ilankumaran, S. I55, l4i6g 01ggg\. : Prabhu,K.R., Sivanand, p.S.,Chandrasek alirn,S.ATCIEE39, 4316(2000). 0lggg). p.,Chandrasekaran, Sinha,S.,Ilankumaran, S. ZZ 40,.7il Benzyltrimethylammonium diphenylphosphinate. stille coupling.l The title compound is an effective scavenger of organotin rcsidues.on precipitating Rjsnop(o)ph2 the cu-catalyzed Stilre coupling reacrions ere tacilitated. Zhang,S.,Marshall, D., Liebeskind, L.S.JOC 64,2jg6(1ggg).

f,f'-BiE

l, l'-Binaphthalene-2.2'-diol. BINOL

Benzyltrimethylammonium tetrachloroiodate. Hydroximoyl chlorides.t Chlorination of aldoximes by this reagent at room temperatureis rapid. rKanemasa. A., Kakinami,T. 256, 1057(2000). H., Kamimura, S.,Matsuda,

Benzyltriphenylphosphonium peroxodisulfate. Oxidation,l Primary alcohols are oxidized to aldehydesunder solvent-freeconditions with this reagent and aluminum chloride as catalyst. Reaction in the presenceof other Lewis acids including FeClr, BiClr, andZnCl, are less efflcient. rHajipour, S.E.,Adibi,H. CL 460(2000). A.R.,Mallakpour,

Benzyl N-vinylcarbamate. Arylethylamines.t The title compound is transformed into an alkylboronic acid via hydroboration and its Suzuki coupling with ArI affords ArCH2CH2NHCbz. rKamatani, L.E.JOC 64,8743(1999). A., Overman,

Binaphane. Asymmetric hydrogenation r (R,R)-Binaphane ( I ) is preparedfrom l.l' -bi-2.2'naphthol in five steps. Its Ru complex is useful for asymmetric hydrogenation of trisubstitutedenamides.

f

1,1'-Binaphthalene-2,2' -iliol (modifed > Cyanations, Aluminum compleres with diarylphosphine oxide groups posses cyanation of aldehydesrand imines: '*'irh

in a manner analogous to the Reisscr asymmetric Strecker synthesis is apphc reactivity of MejSiCN than HCN in rlre g

catalytic amount while supplying stoichro

2\/

(A

C(

Al.dol transfer.a An aluminum con replacementof the carbinol moiety of an I the aldol and an aldehyde in dichlorot transformation.

rHamashima, Y.,Sawada, D., Kanai,M.. Shrbc rTakamura, M., Hamashima, Y, Usuda,H.. K:a 'Takamura, M., Funabashi, K., Kanai,M.. Stxh 'Simpura,L, Nevalainen, V.ACIEE39.3.111 r!

(1)

lXiao,D., Zhang,Z.,Zhang,X. OLl, 16'79(1999).

1,1' -Binaphth alene-2,2' -diol' BINOL. Resolution.t The cyclic boronate ester derived from racemic BINOL and BHl SMe2 preferentially forms a diastereoisomerwith r-proline, thereby (R )-BINOL can be isolatedby crystallization.On decompositionof the complex(S)-BINOL is recovered. rShan, 2Z., Xiong,Y.,Zhao,D.255, 3893(1999).

I,l' -Binaphth alene-2,2' -diol-galliurn/lld 2-Aryloxy alcohols.t meso-Epoxrh Ga-Li linked BINOL complex with high

rMatsunaga, S., Das,J., Roels,J., Vogl.E.\l . M. "/ACS122,2252(2000).

1,1' -Binaphth alene-2,2' -diol-porassiurn/ Addition to imines.t The hererd (l-PrO)1Yb and r-BuOK catalyzes rhe ar N-phosphonimines.

rYamada, K., Harwood,S.J.,Griiger,H.. Shrb.s

I,l'-Binaphthalene-2,2'-diol-potassiurn/yttrrbium complexes

\rmcs by this reagent at foom

:f' :o57(l0OO).

h - : Le

:i t\ des under solvent-freeconditions Rcaction in the presenceof other

1,1'-Binaphthalene-2,2'-diol (modified)-aluminumcomplexes. cyanations. Aluminumcomprexes of BINoLs (1) that are armedat c-3 andc-3' with diarylphosphine oxidegroupspossess bothLewis acidandbasecenters.Asymmetric cyanationof aldehydesr andimines2with Me.SicN, andof quinolinesandisoquinolines3 in a manner analogousto the Reissertreaction is successful(ee- 7G-902o).The asymmetricstrecker synthesisis applicableto conjugated.aldimines and the higher reactivityof MersicN thanHCN in the presence of l0 molToof phoH enablesits usein catalyticamountwhile supplyingstoichiometric HCN asthecyanidesource.

.:llclent.

t,,

tr.:' .' :nrcd into an alkylboronic acid via r:: -:. \rCH.CH.NHCbz.

(1)

'r R

I , is preparedfrom 1,1'-bi-2,2''r asvmmetric hydrogenation of

Aldol transfer.a An aruminum complex of BIN'L is capable of cataryzing the replacementof the carbinol moiety of an aldol. Thus, addingthe complex to a mixture of the aldol and an ardehyde in dichloromethane at room temperature completes the transformation. Hamashima, Y.,Sawada, D., Kanai,M., Shibasaki, M. JACSli2l, 2641(19gg). rThkamura, y., Usuda,H., Kanai,1,f., M., Hamashima, if,ii^"ti, M. ACIEE 39,1650(2000). 'Takamura, M., Funabashi, K., Kanai,M., Shibasaki, frl.]aCS 122,6327 (2000). rSimpura, L, Nevalainen, V.ACIEE39,3422(2000\. l,l' -Binaphth alene-2,2,-diol_galiumlithium complexes. 20,24_25 2-Aryloxy arcohors.t meso-Epoxrdes are op"n"o by phenors in the presence of the Ga-Li linked BINOL complex with high enantioselectivity.

#1))13?ri;iTirl;;fr*,,,

(':

. ctl tiom racemic BINOL and proline,thereby(R )-BINOL can -,'nrplex(S)-BINOLis recovered.

J, Vogr, E.M, yamamoto, N.,rida, r, yamaguchi, K.,Shibasaki,

1,1'-Binaphth alene-2,2,-diol_potassium/ytterbium complexes. Addition to imines.) The heterobimetallic complex derived from BINOL, ll-PrO).,Yb and l-BuOK catalyzes the asymmetric reaction between nitroalkanes and .V-phosphonimines. Yamada, K., Harwood,S.J.,Grriger,H., Shibasaki, M. ACIEE 3g,3504(1999).

l.I'-Binaphthalene-2,2'-diol-titanium complexes

1,1'-Binaphthalene-2,2'-lliol-titaniumcomplexes. 15,26-27;16,24-25;17,28-30; 18, 4344; 19, 25; 20,25-27 Enantioselective isomerization.t Epoxides of enol esters provide chiral a-acyloxy ketones and chiral starting materials. 4-Substituted butenolides, 2-siloxyfurans react with aldehydes2and with imines3 at C-5 to give chiral products. The hydroxyalkylbutenolides formed can be incorporated into the catalyst system thus rendering the aldol reaction autoinductive. Chiral sulfuxides.a A catalytic oxidation of organothiomethylphosphonatesenables the preparation of enantiomerically pure sulfoxides. a,a -Disubstituted amine*s Addition of two Grignard reagentsto a nitrile leads to the products. If a chiral BINOL-Ti complex is introduced in between the additions, the oroductsare enantioenriched.

BnO_CN

-J-'t 99Va

Hydroformylation.l A poll'mer-r catalyst for asymmetric hydroforml L propene)to afford branched aldehr'&s.

reachable). Conjugate additian. A phosphoramidite ligand (1) is useful for chiral induction during reactionoforganozincreagentswithenonesrand4.4-disubstituted 1,5-cyclohexadienonesain the presenceof Cu(OTf)2.

o

ot

Ph

o ' F P-N

o

/""'

Ph

(1)

Allylic tlisplacements.s The mixed phosphite of BINOL and phenol serves as a ligand to make up a catalyst with [(cod)IrCl]2 for the allylic substitution. Remarkable rate enhancement and increase in yield and ee are realized when the reaction is performed with BuLi-ZnCl2 also. Hetero-Diels-Alder reaction.b In the cyclocondensationof the Danishefsky diene and aldehydes in the presence of 2, a remarkably high asymmetric amplification is realized.

C h o n g ,J . M . , S h e n ,L . , T a y l o r ,N . J . . I A C Sl : rvan der Berg, M., Minnaard, A.J.. Schudd I-'eringa,B.L. JACS 122, I1539 (2000r. 'Naasz, R., Arnold, L.A., Pineschi,l\t.. Kclk ' l m b o s ,R . , B r i l m a n ,M . H . C . , P i n e s c h r\.l . I 'Fuji, K., Kinoshita,N., Tanaka,K.. Karahc 'Furuno, H., Hanamoto,T., Sugimoto.)'.. lru -Nozaki, K., Shibahara,F., Hiyama. T. C1.64

I,l' -Binaphth

alene-2,2' -iliyl siloxan-

CyclosilylationI

Yttrocene

compounds while

incorporating

asymmetric induction is poor.

I

cr

a sll

I,l'-Binaphthalene-2,2'-diylsiloxane

;:o '='@

3l

O' P " " ^

o' ' o- l I 3 vu (2)

rr .

'lrhasaki. M. JACS 122,6506(2000).

Hydroformylation.T A polymer-supported (RS)-BINAPHOS complex 3 serves as catalyst for asymmetric hydroformylation of gaseoussubstrates(e.g., 3,3,3-trifluoropropene) to afford branched aldehydes. I .. ., r.rn\ I group donorsof an enone. n:J:, rhosphoramiditeligands containing ,\rth (cod)2RhBFain asymmetric r: ar.: r -.uhstitutedacrylic esters(ee ) 997o p:.: I i. usefulforchiralinductionduring in 1.5-cvclohexadienonesa { : .::.uh\tituted

(3)

,

pi::: ,'1 BINOL and phenol servesas a x ':.; .rllrlic substitution.Remarkablerate i:.:../iJ *hen the reactionis performed

Chong,J.M., Shen,L., Taylor,N.J. JACS 122, lB22 (ZOOO). :van der Berg, M., Minnaard, A.J., Schudde,8.p., van Esch, J., de Vries, A.H.M., de Vries, J.G.. Fcringa,B.L. JACS 122, I I 539 (2000). ')iaasz, R., Anrold, L.A., Pineschi,M., Keller, 8., Feringa,B.L. JACS l2l, I 104 ( 1999). ' l m b o s ,R . , B r i l m a n ,M . H . G . ,P i n e s c h iM , . , F e r i n g aB , .L. OLl,623 (lggg). 'Fu1i, K., Kinoshita,N., Tanaka,K., Kawabata,T. CC 22gg Oggg\. Furuno,H., Hanamoto,T., Sugimoto,Y., Inanaga,J. OL2,49 (2000). ).iozaki, K., Shibahara,F., Hiyama, T. CL 694 (2000).

l. l' -Binaphth

:l .- ':J!'nsationof the Danishefskydiene rt,^ . high asymmetric amplification is

alene-2,2' -diyl siloxane.

cyclosilylationr compounds while

Yttrocene incorporating

esymmetric induction is poor.

1 catalyzes the conversion of a silyl group from

polyenes to cyclic

hydrosilane reagents. However,

-methyl)tindibromide Bis(1,1'-binaphthalene-2,2'

\L

^'"'@/\

9H

"-..P'--' Y'1,,2

,u-*r'

\z

Bis(acetonitrile)(1,5-cyclooctadi€trc ft

' Muci,A.R.,BercaqJ.E.TL 41.7609(200U.

Aryl transfer. The aryl group of . the influence of the ionic Rh complex,

Bis[1-(1,1'-Binaphthalene-2,2'-methyl)-3-methylimidazol-2,2'-ylidene]palladium(II) iodide. Heck reactionr The carbene complex 1 is very stable to air, water, and high temperature. It also survives silica gel chromatography. Preliminary investigations of I indicateits catalyticactivity in the Heck reaction.

\\ tM1

Bis(acetonitrile)cyclopentadienyl( trio tetrafluoroborate.

Slugovc, C.,Ruba,8.,Schmid,R., Kirchr

tl tt \J

I Oi, S.,Moro,M., Fukuhara, H., Kawanrd

Isomerization Efficiency for tb ketonesby intramolecular redox isomcr CpRu(PPhj)2Cl-NH4PF6l,but there is d the substrates.The catalyst is readily pr

t.r/*-

tt-

(1)

I Clyne,D.S.,Jin,J.,Genest, E.,Gallucci,J.C.,RajanBabu,T.V. OL2, ll25 Q0O0). Bis(1,1'-binaphthalene-2,2'-methyl)tin dibromide. Enantioselective benzoylation.t The title compound 1 catalyzes selectivebenzoylation of racemic 1.2-diols.

n'\-\Z'r -

Ph/-voH+Phcocl

/'

jlwasaki, F.,Maki, T., Onomura,O.. Nat st

(1)

oH

phr''t

rffi v\?

|

(1)

,,B r

sri

Br

Bis(acetonitrile)dichloropalladium( tIl 25-26; 17, 30-3 I ; 18, 4445: 19, 26 Thia-Claisen rearrangemenlt h chiral bicyclic thiolactams via a rhio effected with assistanceof (MeCN).pdC

,n,10-Jh ""oJr*F\ S.....^/.Ph

Na2CO3 THF - H2O (50 : 1)

Allylic displacernents. For achieri alkenols to form 2-vinylpiperidinc , VeCN)zPdClz is needed because tl: throughout the reaction.

Bis(acetonitrile)dichloropalladium(tr)

9H :

v

oH +

-;-OBz ph..' \./---

l ph'

-\./- -OH

i

(er 92:8) 41o/o

J

rlwasaki,F.,Maki, T., Onomura,O., Nakashima, W., Matsumura, Y. JOC 65,996 QUn).

Bis(acetonitrile)(1,5-cyclooctadiene)rhodium(I) tetrafl uoroborate. Aryl transfen The aryl group of ArSnMej is transferred to N-sulfonyliminesr under the influence of the ionic Rh complex. lm ida zol'2,2'-ylidenelpalladium(II) .rable to air, water, and high PreliminarYinvestigationsof I

I T:

r Oi, S.,Moro,M., Fukuhara,H., Kawanishi,T., Inoue,Y.fL4,9259 (1999').

Bis(acetonitrile)cyclopentadienyl(triorganophosphine)ruthenium(I) tetrafluoroborate. Isomerization

Efficiency for the transformation of allyl alcohols to saturated ketonesby intramolecular redox isomerization is improved by using these complexes [vs. CpRu(PPh)2Cl-NH4PF6l, but there is the disadvantageof limited substitution patternson the substrates.The catalyst is readily preparedfrom RuClj.3H2O. : Slugovc,C., Ruba,8., Schmid,R., Kirchner,K. OM 18,4230(1999).

r tt.2. ll25 (20O0)-

ldt.

r'.

::J I catalYzes setective benzoYla-

Bis(acetonitrile)dichloropalladium(Il). 13, 33, 2l l, 236; 14, 35-36; 15, 28-29; 16, 25-26; 17,30-31; 18, 44 45; 19, 26 Thio-Claisen rearrangement.t Introduction of a side chain to the c-position of chiral bicyclic thiolactams via a thio-Claisen rearrangement at room temperature is effected with assistanceof (MeCN)2PdCl2.

,,oJ-\

Ph,',(

|

|

)-Nvz\ MeoJ 5=.-r1--tn a

\

V' 2

J":tr (exo: endo 3:1\ 650/o

/

\,

(MeCN)2PdCl2

Br

Na2co3

Sn

Br

lHf_tr2v

( 5 0; 1 )

Allylic displacements. For achieving dehydrative cyclization of N-Boc-7-amino-2alkenols to form 2-vinylpiperidine derivatives,2 only a catalytic amount of ,\{eCN)2PdCl2 is needed because the Pd(II) species maintains its oxidation state throughout the reaction.

Bis(acetonitrile)dichloropalladiun(II)

OBn

OBn MOMO

MOMO

(l\4eCN)zPdClz THF 25'

rWatson,D.J., Devine, P.N., Meyers..{.1. II, rYokoyama, H., Otaya, K., Kobayashr. H. (2000). rLautens,M., Renaud,J.-L., Hieb€n. S. ./..1( rYang, F.-Y.,Wu, M.-Y., Cheng,C.-H- l.f CS sFielder,S., Rowan, D.R., Sherbum. Il.S .{(

OH fung opening of 1,4-oxa-1,4-dihydronaphthalenewith R2Zn proceedsin the presence of (MeCN)2PdCl2to afford cls-2-alkyl-1-hydroxy-1,2-dihydronaphthalenes.l Acylboration, Allenes are functionalized to give 2-acylallylboronates on reaction and acyl chlorides.a with bis(pinacolato)diboron

R + R"COC| + R'

]-o. |

l-d

p-L B-B

I 'o1-

Bis(allyl)dichlorodipalladium.

20. l9

Allylic displacements. Glycine dr with an allyl carbonate.rBINAP medral is rapid. The reaction with 2-bromo-1.3{ren Similarly, 3-bromo-3-alken-I -ynes are s butaLrieneproducts.aIn this reaction.

(tr4eCN)zPdClz

addedlieand.a

PhMe 80"

MeO Stille coupling.s An expedient synthesisof [6]dendraleneinvolves coupling of 2,3bis(trimethylstannyl)-1,3-butadienewith 3-iodosulfolene and pyrolysis. A lesser amount of [8]dendraleneis also produced.

Ph'\
["4il-",+''' Nl..\lurel S..Mitsuhashi. Kondo,K., Morohoshi,

(1) rHanessian,S., Johnstone,S- JOC 64,5896 (1999)'

-tosylhydrazine. 1-l-Butoxycarbonyl-1 carbonyl compoundsundergoreductivecondensation hydrazines.t substituted by selective from 1,2-di-t-Boc-l-tosylhydtazine prepared is which with this reagenr, hydrogenolysis.

Tt N-NH2

o
< l-BuOOH in the presence Allyl alkyl ethers are converted to ketoness on reaction with This oxidation temperaturc. room at of a catalytic amount of cro.1 in dichloromethane does not affcct THP, TBS, and MOM ethers' alkenes by Pd(oAc): is Arylation of alkcnes.(, Coupling reaction of arenes with reoxidant. Note, this is as a carried out in the presencc ol' benzoquinone ancl l-BuooH

,-N a'

lDumestre,P, El Kaim, L., Gregoire.A. ('C'--:

l

n o t a H c c k r e a c t i o n ( i n v o l v i n g A r H i n s t e a do f A r X ) ' r G u r u n a t hS. . , S u d a l a iA , . Sa 559( 1999). r P e s i r i ,D . R . , M o r i t a ,D . K . , W a l k e r T , . , T u m a s , W 'O M 1 8 ' 4 9 1 6 ( 1 9 9 9 ) ' r L e a d b e a t eN r ,. E . ,S c o t t 'K . A . J O C 6 5 ' 4 7 7 0 ( 2 0 0 0 ) ' r F a s s l e rJ, . , E n e v ,V . , B i e n z 'S . H C A 8 2 ' 5 6 1 ( 1 9 9 9 ) ' 5Chandrasekhar, T 5'L 1063(1999)' S.' Mohanty, P.K, Ramachander, r ' J i aC , . , L u , W . , K i t a m u r aT Y O L l , 2 O 9l ('1999)' F u j i w a r a , . ' ,

Butyllithium. 13,56; 14,63-68; 15, 59 61 . Various usesof BuLi lor & Lithiation. reactwith aldiminesto provide precursor\(tf

l'uransare readily preparedvia alkylation ,.i i Allenamidesare functionalizedat thc o-p tion. Thus, on introductionof an alkynl I cha rcaction can be prepared.3Lithiation oi ihe O -C transsilylation.{5 cngenders

13,55;18,14:19,54 /-Butylhypochlorite. Nitrosoarenes.N.Arylhydroxylaminesundergooxidation(5examples,88-92Vo).

P-

(1999)' rDavey, M.H.,Lee,V.Y, Miller,R.D.,Marks,TJ IOC 64' 4916

polymer 2.1-Butylimino-2-diethylamino-3.methyIperhydro-l,3,2.diazaphosphorine, bound. N.Acylation.|Thepolymer-supportedbaseladequatelyservesforuseinthe acylationof weakly nucleophilicamines'

oAN)

f-l oANAR

u".l: f_A.

-;-

\-^ " \

|

llll R'

Butvllithium t : irr/aphosphorine, polymerbound

>.

I I __.{-\_ \ru' \--l )*-r,-*

t. :rl

-'rrlic acidsrin moderateyieldsby ..,rrlr zed epoxidationof unsaturated .,,und cobalt-phosphinecomplex is

r |A

\--r*(1)

;.rn.lirrmed into ct-silyl-p-hydroxy lKim, K., Le. K. SL 1957(1999).

o o H

l-Butyl isocyanide. Reaction with nitro compound.s.l Homologation to afford ct-oximino amide derivatives is observed.

7'i---""' .retr()nwith t-BuOOH in the presence temperaturc This oxidation .rt r(x)111 ts : .rrcncswith alkenesby Pd(OAc)2 is this Note' reoxidant' a UuOOH as

it r r . : \

'lr

r,rl6(1999).

l l

('i I 199(l)'

r _

r(. j

.

r,)(lI.

rDumestre,P, El Kaim, L., Gregoire,A. CC 715 (1999)'

'74-'l'7; L9,54-59',20,62-65 Butyllithium. 13, 56; 14, 63-68; 15, 59-61'.17,59-60; 18, that subsequently ethers include deprotonation for Bul-i of Lithiation. Varioususes tetrahydro2-Alkylidene pyffolidin-3-ones.r of precursors rcact with aldiminesto provide 2-sulfonylmethylenetetrahydrofuran.r of furansare reaclilypreparedvia alkylation lithiaAllenamidesare lunctionalizedat the ct-positionby virtue of thc regioselective Pauson-Khand the of precursors valuable chain, tion. Thus, on introductionof an alkynyl or allenyl alcohols reactioncan be prepared.rLithiation of the silyl ethersof propargyl * C transsilylation.r' c n q e n d e rOs

,.:r,) o\idation(5 examples'88-927o)' h.l. lei6

Pr

( 1999).

polymer lpt rhr dro- 1.3.2-diazaphosphorine' t-

63%

in the ..r I eticquately serves for use

P-r

o4uAR Pf oA*

(-. -\\

BuL: -^--\. R ;* I

lll I

R'

"--

oAr.rAR N,4o(CO)6

.,\'-^

t

q

t

F

o

Butvllithium

il

v. -:i


oHc..,/\ i l l \z\NN/e,

]:Y-fi / r)-

"

\Z\Nvr",

/

MeO

-

\

/

oEt + Bu-Lt OEt

81Yo

of the silyl enol The above revefse tlrook rearrangementalso occurs during treatment gives an PhcHo with with BuLi. Quenchingthe enolate ether of o-bromoacetophenone aldol product.6 createsa new nng' Halogen-lithium exchangefollowed by intramolecular substitution presence of two The Such a method is the basis of a benzodihydrofuran synthesis. exchangeablehalogenatoms(2,6-disubstitutionpattern)makesitpossibletointroduce al C-7.7 anotherfunctionalitY

The halogen-lithium exchange of regioselectivityin ether and toluene.r: N-Acylntion.ts Primary arylamirrs subsequentexposureto an ester at lo$ tem Wittig reanangements.tt Solvent e ment of benzYl ProPargYlethers.

'b""-

BuLi/ THF

fi{osivreo VBr

7 4o/o

Br B u L i/ T H F

)'-.-.o",

t

i

\,"\Br

l

l

\Br

HCONMe2

oYo Et2O , O" EtzO-THF - hexane -110' 62%

f1^

lYt i l

V\cHo 76Yo

by Sn-Li exchangeand O,Cs-Dilithio enolatesare generatedfrom p-stannyl ketones enolization.n Alkenes'(Phenylsulfinylmethyl)diphenylphosphineoxideisreadilydeprotonated sulfoxides.' for condensarionwith aldehydes,affording (8)-alkenyl phenyl by elimination of terminated is olefination Julia-Lythgoe of the A sulfoxide version r') vicinal hydroxyl and phenylsulfinylgroupson treatmentwith BuLi Solventdependence,solventdependenceoftheproductsarisingfromeither with BuLi has been isomerizationor elimination of propargylic acetalsrron treatment witnessed.

rAmombo, M.O., Hausherr,A., Reissig.H -L' 2Edwards,G.L., Sinclair,D.J.TL&' 39-1-rt l9 rxiong, H., Hsung,R.P, Wei, L.-L', Beq. CJ aSakaguchi,K., Fujita, M', Suzuki,H.. Htges sstergiades,LA., Tius, M'A. JOC 64"15t '1rl' 6Comanita.B.M., Woo, S., Fallis' A.C. fL a. TPlotkin,M., Chen, S., Spoors'P.G.IL 41. 8Ryu, I., Nakahira, H., Ikebe, M., Sonoda \ . evanSteenis,J.H., van Es, J.J.G.S.'van dcr G roSatoh.T.. Hanaki, N', Yamada,N., Asarrc. T rrLe Strat,F., Maddaluno,J.TL4l' 5367 tlffi r2Wang,X., Rabbat,P.,O'Shea,P.,Ttllyer. R . rrooi, T., Tayama,E., Yamada' M.' Mantob I raTomooka,K., Harada, M., Hanji' T.. Natar. 1

,.j

Butyllithium

Eto. -oEt

Et2O

/

NMe2 MeO

81%

oEt + Bu-Li

_-lr;-

OEt

I

f,.-

1l:

It r.

- Juring treatmentof the silyl enol rhc cnolatewith PhCHO gives an s n e wr i n g . . . . r r . u h s t i l u t i ocnr e a t e a ': .rnthesis.The Presenceof two ::r , makes it possible to introduce

/oEt

ttt- 40.

)

/:c--/

MeO

I

F.C=C-J MeO

The halogen-lithium exchange of 2,5-dibromopyridine also shows different regioselectivity in ether and toluene.12 N-Acylation.t3 Primary arylamines form amides on dilithiation with BuLi and subsequentexposureto an ester at low temperature. Wittig rearrangements.t4 Solvent effects dominate the mode of Wittig realrangement of benzyl propargyl ethers.

o o H

r l l

-_.r^\-

I

pn

'4siM".

"bfu *G(."".fl.o.--q

74lo

0% E t 2 o ,o ' Et2O-THF- hexane - 110" 62%o

55Yo

14To

4%

8Yo

Yr l

\-^cHo 76%

:i I kctonesbY Sn-Li exchangeand rl: l- ..

l: f,_-

t

rLnc oxide is readily deprotonated . phcnylsultoxides." r,,n is terminatedby elimination of ' n ts i t h B u L i . r 0 rhc products arising from either \rn treatmentwith BuLi has been

rAmombo, M.O., Haushen,A., Reissig,H.-U. SL 1871 (1999). r Edwards.G.L.. Sinclair,D.J. TL 40, 3933 ( 1999). 'Xiong, H., Hsung,R.P.,Wei, L.-L., Berry, C.R., Mulder, J.A., Stockwell,B. OL2,2869 (2OO0). lsakaguchi, K., Fujita, M., Suzuki, H., Higashino, M., Ohfune, Y TL 4l' 6589 (2000). 5Stergiades, 1.A.,Tius, M.A. JOC 64,'154'1(1999). nComanita,B.M., Woo, S., Fallis,A.G. TL 40, 5283 (1999)' -Plotkin, M., Chen, S., Spoors,P.G.TL 41,2269 (2000)' rRyu, 1., Nakahira, H., Ikebe, M., Sonoda,N., Yamato, S., Komatsu, M. ./ACS 122' l2l9 (2000). 'van Steenis,J.H., van Es, J.J.G.S.,van der Gen, A. EJOC 2781 (2000). rSatoh,T., Hanaki, N., Yamada, N., Asano, T. T 56,6223 (2000). rLe Strat.F.. Maddaluno,J.TL41,536'7 (2000). rWang,X., Rabbat,P.,O'Shea,P, Tillyer, R., Grabowski,E.J.J.,Reider,PJ. TL 41,4335 (2000). 'Ooi, T., Tayama, E., Yamada, M., Maruoka, K. SL'129 (1999)' 'Tomooka, K., Harada, M., Hanli, T., Nakai, T. CL 1394 (2000)'

TMEDA

Butvllithium-N,N,N'N"tetramethylethylenediamine'

LI

Butyllithium-2-(N,N-dimethylamino)ethanol' Lithiationofpyrid'ines.3-MethylpyridineisregioselectivelylithiatedatC-6with thisbasesystem,lwhichismarkedlydifferentfromitsbehaviortowardLDA(benzylic lithiation,).2-Chloropyridinebehavessimilarly'2

,*k 7\-6

N--w

Buli - TMEDA EtzO - 100'

rMathieu, J.,Gros,P, Fort,Y'CC951(2000)' rChoppin,S.,Gros,P.'Fort,Y'OL2,8O3(2000)'

a

\1

Butyllithium-potassium r-butoxide' Cyclization.lFusedl-vinylcyclopropanesareformedonlithiationofallylsulfides that bear an alkenyl chain at the ct-position'

/ (

SPh

-\Z\

CeH

BuL.,.BuoK -rHF CA l+ L-lX'"'*,'l

a- K",r,, 81Yo

Lithiation.rn-Methoxybenzoicacidand3,5-dimethoxybenzoicacidarelithiatedat c-4.2 rCheng,D., Knox, K.R., Cohen,T' JACSl22' 412 (2000)' S TL 41' 3 157 (2000)' 2Sinha.S., Mandal, B., Chandrasekaran,

|

17-i 9' ll s-Butyllithium . 14, 69; 16, 56; 18, Lithiation of aromatic compounds' H are lithiated at the ortho position'' Indole-2-carboxylic esters'1 Benzlhc mates followed by addition of alkyl oralatc treafl indole-2-carboxylicestersynthesison

v"-tY* 11

Ff

M;|o

n

R'

I '

.).tcr.ni basedon transannularadl,,sing the Br-Li exchangeof a

>( o q TBSO 44-60Yo

t-:' f,

, r.rln Sr2' process.6 ;thiutnsalso)addsto the termlnus ,' rubstratescontain an allyloxy or ,, thc benzylicPosition.T

/-BuOCONHOMs, and the subsequenttreatment with zinc triflate, 2'6-di-r-butylpyridine' benzylalcoholinMeCN.BenzylcarbamatesRNHCooBnareobtained. rStafford, S. S.,Barrett,D. G., Suh,E' M', Feldman'P'L' JOC 63' 10040(1998)' J.A., Gonzales, I -Butyl-3-methylimidazolium salts. 20, 70 have Allylic displacements.t Palladium-catalyzed allylic displacement reactions temperature' room been carried out in ionic liquids at rChen.W., Xu, L., Chatterton, C., Xiao, J' CC 1247(1999)' N-(t-Butyl)phenylsulfi nimidoyl chloride. by N,Noxidntion of alcohols. This stable reagent,r prepared from r-BuNH2 as the fashion same in the functions PhSAc, with dichlorination and then treatment efficient which With oxidations. Corey-Kim and reactive speciesgeneratedin the Swern presence of DBU oxidation of alcohols is performed in dichloromethane in the (1 1 examples,90-99Vo).2 enolates on conjugated ketones.t Dehydrogenation of ketones via their lithium -78' convenient' is very treatment with r-BuN:S(Cl)Ph at A.V "/oC(UssR)9, |435 (|973). lMarkovskii, 8.S.,Kirsanov, T.N.,Levchenco, L.N.' Dubinina, rMukaiyama,T., Matsuo,J.,Yanagisawa, M. CL lO72(2000)' rMukaiyama, H. Cf 1250(2000)' T.,Matsuo,J', Kitagawa, f-Butyl propynoate. (via a double Michael Protection of l,2-diols.l Acetal formation with this ester to l,2-diols (1,3- and is limited reaction) at room temperature in the presenceof DMAP conditions that survive acetals l,4-diols do not react rn a similar manner). These bases' with cleaved acetonidesare hydrolyzed (e.g., aq HOAc) but they can be rAriza,X., Costa,A.M.,Faja,M.' Pineda, O', Vilanasa'J'OL2' 2809(2000)'

OH

/-Butylsulfi nyl chloride. homolysis at Amide radicals.t After O-sulflnylation, hydroxamic acids undergo This structures. to cyclic bond. Trapping of the N-radical by an alkene leads the N-{ method has been applied to a formal synthesisof peduncularine'

I

r .

(' . lcng. L.0L2,489 (2000)

M"ofl

*o)*{

t-BusOCl/ iP12NEt CH2C!2 Ph2Se2

: thc rearrangmentfor degradation lr. r':'.-:' :rJtng acid chloridesRCOCI with

- \ o

-sePh

-{

l-,

rueo-,\

r-

-=*

) peduncularine

(r-Butylthio)azoarenes

' Lin, X., Stien,D., Weirneb,S.M. ZZ 41, 2333(2000). 2-(l-Butylsulfonyl)allyl chloroformate. Amine protection.l Carbamates are formed at room temperature or below. The removal of the protecting group, is most expediently achieved by treatment with a polymer-bound secondary amine. The released fragment is trapped and the isolation of amines is uncomplicated. 'Carpino,L.A.,Philbin,M. JOC 64,4315(1999).

Calcium hypophosphite. Reduction of arenediazonium ions. (e.g., MeCN) to remove amino groups fro

yields are obtained from substratesthat conu

2-(t-Butylsulfonyl)phenyliodine(II! diacetate. Hypemalent iodine reagents.' This compound is obtained from t-butyl 2-iodophenyl sulfone by oxidation with H2O2-Ac2O.It can be transformedinto reagentssuch as 1 and 2.

\ l P

\ l o

id=o

is="

\_y'-\o

\__/-\*,.

(1)

(2)

rMacikenas, D., Skrzypczak-Jankun, 8., Protasiewicz, J.D.,IACS121,7164(1999). 1-t -Bu.tyl-lH -tetrazol-5-yl sulfones. (Z)-Alkenes,t These sulfones are very stable and participate in the Julia olefination with improvedyields. rKocienski, P.J.,Bell,A., Blakemore, P.R.SI,365(2000).

rMitsuhashi, T., Suzuki.H. fL ll. H., Kawakami,

Carbon dioxide. Carbonates and carbamates, In th alcohols combine with CO, to afford carho different conditions2,and with a Mg-Al mr The preparationof dimethll < carbonates.3 supercritical carbon dioxide in the pres methoxide) is successfully carried out.' Carbamates are formed by trapping th. with alkyl halides.sThe initial step is Fn

Heatins aminesand oxetanesat 40 atm lead

[--l +COz+R,NH l

^

2,4-Dihydroxyquinazolinesare obtaincd of an aminesuchas DBt'.' in the presence

(l-Butylthio)azoarenes. Hydrazones.t Reaction of ketones with these reagents conveniently introduces an arylhydrazono group to ketones.

CN

-r)

NHz

o

*A ' C a p o s c i a l l iN , . , D e l l ' E r b a ,C . , N o v i , M . , P e t r i l l o , G.,TavaniC , . 254,5315 (199S)

Reaction medium,

By virtue of it-sar

its increasingapplicationsas a reactionnrc with oxygen and PhCHO, rhodium-F

:\ _:rn -ot

x@ { -

F

,10A)

oAtt-R' -^-7--\ \ /

R > (12) R = Me, R'= COEI R = Ph, R'= CHzMe Displacements involving allylic systems. Allylic substitution reactions continue to receive considerableattention.Improvement by microwave is noted.3oNew ligands for the Pd-catalyzed reaction include iminophosphine 13, which is derived from lmesitylethylamine,rrpyridylphenylphosphine 14,32and the phosphinite 15, obtained from o-glucosamine.rrPhospholanessuch as 16,17, lg, preparedfrom mannitol, are excellentligands.sa

Chiral auxiliaries and catalysts

-g,?-.# Fe \l-,,

=(13)

(15)

(14)

(22\

Y

a''(" \A^-

oj.-(

Xofr'-'n

ix^ "^i-' " l

H 7 -

(16)

(17)

Metallocene-catalyzedring opening ol and organometallic reagentsa2proceeds ur based on the planar chiral ferrocenyl unrt presenceof both the r-acceptor phosphon

cently synthesized4S-ligand is 26.il Chiral ligands related to BINAP and us. text are 274sand28.46The aldimine represr

(18)

--}-sur" There is a remarkable reversal of enantioselectivity for reactions involving a bis(oxazoline) ligand 19 by merely changing the oxygen arms.3514-Diphenytphosphinoethyl) oxazolines20 representa secondgenerationof theseclassof ligands,being superiorto the lower homologues(the phosphinomethylcompounds)and as effective as the wellknown benzologue.36Placing the phosphorus atom at a bridgehead of the norbornadiene skeletoncreatesrelatively rigid phosphinooxazolines(21).37The planar chirality of the modified ferocene moiety in 22 is responsible for the stereochemicalcourse of the allylic substitution,so in thesecasesthe stereocenterin the oxazolinering plays at most a

B; (25)

minor role.38 With ligand 23 derived from B-pinene, the reaction of cinnamyl 2(benzenesulfonyl)vinylethers shows that vinylogous sulfonatesare viable substrates.r') A study on the acyclic fN-ligands 24 manifests the importance of substituent effects (bestwithR:NMe).ao

(27')

(oY*

a/-(t-Butoxycarbonyloxy)butenolide rs n

f,,"

chirality. In a formal synthesisof aflatorrn subunit.{tAllllic a-; rhe furanobenzofuran "chiral i with PhSO2Na, the products are reaction leading to branched products *rd

R=H,Bz

(1e)

(20)

(21)

and the I colinoyl-1,2-cycloheanediamine#

Chiral auxiliaries and catalysts

Ph'\94_o

tn-t ,u*t*l rn Vo

A

(15)

, I

-

a-:a" : I lt vp_\

A

H.^)--

Fe

-t'-

| -,,-

(22\

Y l

\

Y

R(rl.x#-

n

" l n'

,i-)

NPh'PPh t,H

Ph-P-Ph

ffY

(24\

(23)

Metallocene-catalyzedring opening of 7-oxabicyclo[2.2.l]hepteneswith alcoholsal proceedswith very high ee. Novel fS-ligands (e.g.' 25)' and organometallicreagentsa2 based on the planar chiral ferrocenyl unit,a3render good electronic control due to the presenceof both the tr-acceptor phosphorus group and the donor thioether. Another reS-ligandis 26.44 cently synthesized,fl Chiral ligands related to BINAP and used in the Pd-catalyzedallylic displacementcontext are 27a5and28.16The aldimine representativesof the latter seriesare not effective.

(18)

r..

. :,]r rcactionsinvolvinga bis(oxa-

t-1-Diphenylphosphinoethyl) lr,:::.' hr., . ..r.. of ligands,being supertorto 1r:. ,:.J' r and as effective as the wellc. , , hndgeheadofthe norbornadiene 'l:: ,- ll t The planarchirality of the .tc'tcochemical courseof the al[r : tc: ::'.corazolinering playsat most a ;: -' J. the reaction of cinnamYl 2-

-->_SH,r" n

(25)

"^

|

(26) AT

I tlAAr

are viable substrates.re E -. ..rll()nates !. - .nrn()rtanceof substituenteffects

At

N\, I

Ar (27)

(21)

(28)

1-(r-Butoxycarbonyloxy)butenolide is readily transformed into aryloxy analogueswith chirality. In a formal synthesisof aflatoxin B, such a reaction precedesthe elaboration of the furanobenzofuransubunit.4TAllylic acylals also afford chiral sulfones in the reaction "chiral aldehyde" equivalents.asThe Mo(0)-catalyzed with PhSO2Na, the products are reaction leading to branched products with excellent ee is catalyzed by trans-N,N'-dipi' analogue29.50It also and the bis(oxazolin-4-carbonyl) colinoyl-1,2-cycloheanediamineae

102

Chiral auxiliariesand catalYsts

has proven to be valuable in the preparation of 3-substituted 1,4,6-alkatrienesfrom2,4'6alkatrienylcarbonates.By using ligand 30, productsare obtainedin good ee.sl

rq ":x'rY

Variable enantioselectivities are obsen presenceof ligand 35.63p-Hydroxyaldehld with a chiral allyltitanium species36.s *b pared from 37 by various organometallicn mercially available and inexpensive' are ! mediated allylation, even though thev trx Allylation such as that effected by 3E affon lation.67

-\\.,,\NH ,,.NH

o/'",(*-r\

5l'r^f") ono"'Y

LO

(30)

(2e)

o._rr\

of epoxides and aziridines. An observation that concerns the by SiCla in the presenceof 3l indicates a enantioselectiveopening of meso-epoxides beneficial effect of the o-methoxy group to form an octahedralcomplex.srB-Titanoxy A chiral Cr-salen radical intermediatesare involved when using 32 to open epoxides.ss complex has been used to mediateepoxide opening with KHF2. Although the ee values

HOD

opening

(34)

are moderate,this is the first reportof fluorohydrinformationby such a method.s{ 2,2-Disubstitutedepoxidescan be resolvedon reactionwith MerSiNr in the presence of a chiral (salen)CrN,complex.ssGood enantioselectivityis associatedwith the enanwith MerSicN mediatedby (pybox)Ybcl.r.s6sitioselectiveopening of rueso-epoxides

.o ' )-cno \ /

/-o1-

o

multaneousactivationof both epoxideand cyanideis indicated' chiral vinylglycidols containing a quaternary carbon center are obtained from prodracemic vinyl epoxidesvia ring opening with 2-methoxybenzylalcohol. One such of (-)-malyngolide.sT uct hasbeenusedin a synthesis proximal Co-salencomplexesthat are part of a dendrimershow cooperativereactivity 33 is the optimal cal in catalyzingepoxidering openingwith water.s8'Chromium-complex with MeiSiNj's8b reaction on azides to chiral meso-azindines rtng fbr conve B-amino alyst

all

N.^ -o UT

d N 3 Ticl2

(32)

The chiral sulfoxide 39 is valuable l-or ; reaction with aldehydes (low ee with keto aldehydeshas certainsyntheticuse'6" such ar { I, I -Bis(borylmethyl)ethylenes D 1.5-diols of bidirectionalsynthesis usuallyhigh.

t\?

(31)

(37)

(33)

several protocols have been developed for the preparation of Addition to c-.4, chiral cyanohydrinsor their trimethylsilyl ethers.Catalytic systemsincluding vanadyl-salen are eft'ective. complex,5e(pybox)YbClj,60zirconium-TADDOLate,6r and the 34-titanate62

Chiral auxiliaries and catalysts

from 2,4,6F, . -.i l.-1.6-alkatrienes a:- -:.rlncdin goodee.sr

Variable enantioselectivitiesare observed during allylation of aldehydes in the presenceof ligand 35.63p-Hydroxyaldehydescan be allylated in the unprotectedform with a chiral allyltitanium species36,64whereas c-hydroxyaldehydes are readily prepared from 37 by various organometallic reactions.65cinchona alkaloids, being commercially available and inexpensive, are suitable chiral promoters for the indiummediated allylation, even though they induce only moderate enantioselectivities.oo alkyAllylation such as that effected by 38 affords products useful for substrate-based lat10n.

-Ph

Hot'-en

5l'r^r") ,r

l h

t.: -

(\

-7-\

"l-

..!.r\ation that concerns the :rc presenceof 31 indicates a '.,hcdralcomplex.s2 B-TitanoxY ' cpoxides.5r A chiral Cr-salen KHF.. Althoughthe ee values

1-

HOl-v

(36)

(35)

(34)

. ,'n bv sucha method.5a " s ith Me.SiNj in the Presence :.. i\ associatedwith the enanSi-'Jntcd by (pybox)YbCl,.56

.o - !cHo r y

Fo{-

o

,.rtc'd.

! t!'

6,>9

%o"'Y

(30)

^, n center are obtained from . ^rnz1I alcohol. One such Prod-

tt/.-

/

i-PrOOC,.. " n

('"' I B )-: (J

/

Ph

-J

J

i-ProoCT

(38)

(37)

I

3

':r('r \how cooperativereactivity . :-c()nlplex33 is the optimalcat-

I

:.'. ()n reactionwith Me.SiNq.s8b

The chiral sulfoxide 39 is valuablefor assemblageof 1-butenolideson lithiation and The 1-selectivealkylation of 40 with reaction with aldehydes(low ee with ketones).6E use.6e aldehydeshas certain synthetic such as 41 are useful assemblingplatforms that allows 1,1-Bis(borylmethyl)ethylenes Diastereoselectivityand enantioselectivityare 1,5-diols.T0 bidirectional synthesis of usuallyhigh.

,-/

'N"

H

,

(33) h. l:.

\ ',dt X-,:'1 0

.:lcloped fbr the PreParationof , .r stcrlSincludingvanadyl-salen : rlrc3{-titanaten:areeffective.

-)-

-)-o

v

9r|i-)

-,rr"d N

)

( OTBS

/(3e)

/

(40)

Chiral auxiliaries and catalysts

Phosphoramideligands represe lation and aldol reaction. Their prq Aldol reactionwith l-proline as eratinganri-diols.3s Transitionstar

@t'-l'Td (41\

A direct synthesisof chiral propargylic alcohols from l-alkynes and aldehydesin the presenceof Zn(OTf)2, Et3N, and (+)-N-methylephedrinehas a broad scope.TrSeveral new ligands are found suitable for inducing asymmetric addition of R2Zn (mostly diethylzinc) to aldehydes.These include 42,1243,1344,1445,7sand 46.16Other B-amino which is more alcohols that show desirable features are 3-exo-morpholinoisoborneol,TT stable in air than the dimethylamino analogue, (S)-2-(pynolidin-1-y1)-1,z,2-trtphenylethanol,T8 and a polymer-supported N-alkyl-o,ct-diphenyl-l-prolinols.Te N,N-Dibutylnorephedrineis useful in a solvent-free reaction.80

!-< \/-NH

ri. ,'N=

r.P< l l

|

\

\Ap-r l ) a--J

(e3)

/

(e4)

r

)-een2

\-rrn, '

(e5)

PPh2

(-z< [""n'**"

(e6)

116

Chiralauxiliariesandcatalysts

carAmong the effective diphosphine-Ru-diamine complexes used for catalyzing atoms phosphorus the in which member one is enantioselectively bonyl hydrogenation re7 are attachedto a l2,2lpatacyclophaneunit. in the The principle of asymmetric activation-deactivation has been demonstrated racemic of Ru complex a of consisting system a catalytic using ketones of hydrogenation following dimethyl-BlNAP and two chiral diamines.re8The principle is depicted in the diagram.

(es1 substrate

[ _

trs)-*al @ u_ L=:l ffffffffffffffff/nr-*fl g

_____\ llrst-catl l(s)AJ ----)PRoDUcr

l-

:

,

| | rn;-cat1""'l(n)-oeact I -_)

asym Platinum catalysts modified by cinchona alkaloids have been developed for of complex Ru the and metric hydrogenation of ct-keto acetalsreeand a-keto esters,2O0 chiral 2-(MeO)BIPHEP 97 has been developedfor B-keto sulfone reduction.2Ol p-keto esters Ruthenium-basedasymmetric hydrogenation of ct-arylacrylic acids and

Good resultshave been obtained from h1d of indolesurt cationiczirconocenecatalyst,205 2-(MeO)BIPHEP-Ru a and of 2-pyroneswith Very efficient ligands that complementt' ' are l0l.: droaminoacids(and derivatives) 87 with Rh+ has the versatilityof catalrnne and conjugateaddition.2r'

usesthe bipyridylbisphosphine98 (and its enantiomer)'202

OMe

HO

o MeO

PPh2

MeO

PPh2

MeO

PPh2

MeO

PPh2

(J

Pl

Ph2P.Rh/

(} OMe

(101)

il

(e7)

(cod)zRhBF+ The ferrocenyldiphosphineligand 99 constitutes a catalytic system with Seccompounds'2{)3 alkylidene for synthesizing ct-alkylsuccinic acid derivatives from the using acetates enol of ondary acetatesin chiral form are accessiblefrom hydrogenation the catalytic system of (cod)2tthBF4-100.2s

The paradoxconcerningthe generattonc and,\'-t I -r-l 't N-( l -phenylvinyl)acetamide of sutrsu mode .r()odon the groundsthat the stere(^-iE :hc catalyticcycle determinesthe

Chiral auxiliaries and catalysts

tt7

carF i..-'. used for catalYzing atoms 1- .irruh the PhosPhorus n :..:- heen demonstratedin the lt::' : ,'i a Ru comPlexof racemrc r: . :. dePictedin the following

-

r

L.

I

substrate

PRODUCT

J

)

e a- :

-

,.: heen develoPedfor asYm and the Ru comPlex of c ' :.. '.-.I,tnereduction'2ol u*. ,-:rlic acidsand p-ketoesters

Good results have been obtained from hydrogenationof tetrasubstitutedalkeneswith a ?06 of indoles with a bis(ferrocenylphosphine)-Rhsystem, cationic zirconocenecatalyst,205 and of 2-pyroneswith a 2-(MeO)BIPHEP-Ru complex.2{)7 Very efficient ligands that complement (cod)2Rh+salts for hydrogenationof dehyand 103.2r0A combinationof ligand 102,20') droamino acids (and derivatives)are 101,208 87 with Rh+ has the versatilityof catalyzingasymmetrichydrogenation,hydrosilylation, and conjugateaddition.2rI

OH

----( I

)" oH

a-

a-Y':'.,.--

12 \PPhz

\-\r{

PPh2

I FOH ,.'\\,/ \ : \ b x (101)

-/^ Ho1 Ho"'\ ) " (/-o,

Ho

ro r-.. o o

Ph2d\

\oeen, 6.!",oeen'

-\u

..'PPh2 Rh

/\ ^

NJ\ \--r

(102)

(103)

98

r-:1.,.rttc systemwith (cod)zRhBFr Sec| ::.- .1ik\lidenecompounds.203 uslng acetates i.:: :r'nition ofenol

The paradoxconcerningthe generationof oppositeenantiomersin the hydrogenation of N-(l-phenylvinyl)acetamideand N-(l-t-butylvinyl)acetamidewith 104 is now understoodon the groundsthat the mode of substratcdocking at the migratory insertionstepof the catalyticcycle determinesthe stereochemicaloutcome.2rr

Chiral auxiliaries and catalYsts

f18

\11

H.

NHAc

\ D .

ANH

Y i r' l-'oY1n.^ ;

,i-l

I "

NHAc a Ph/\ 99% ee

rl ,,\J '-;n''' . \o/ "'( ."'' \,1

/

r12

b

\4

S

/

BFA \

Accessto bicyclic enonesfrom 1.6-en1n

cnantioselectiveby installing a chiral t-bu cr-benzylidene-aroylacetamidesto furnish -1

z'J*{' ->-; I ri H.

Yti-ri-,"^*t^' { l''1.,X

,\,

Heterocyclic analoguesof BINAP, such ar -bis(diphenylphosp 2,2',5,5' -tetramethyl-4,4' and testedin the Heck reaction.22rIncorporarx sulfinyl group to a double bond elicits eru intramolecularHeck reaction.222 Opticallr a ides are produced from (R)- 1-t-butylsulfin1lc1 Palladacycle (109) and its analogues ind

rearrangement of allylic imidates.22rFor a thioamides, it is convenient to allylate thr dine.225 This processinvolvesa thio-Claisenn Enantioselectivedeprotonation of ketorrs sium bis[N-benzyl-N-(ct-phenethyl)] amide,: :" tonationof enolates.227

(104)

/

NHAc \,/ I

I

l

/

L >-\

H.

do9in ,.' A \ |/ / t - ->NH

i fi- ),pn4 / " \ \ l

PhA

/

\,/

,)f'^\ I

rnduction when the amide moiety is denrc ,rne.22e Chiral ligands for the Pauson-Khand horane(111) derivedfrom (+)-pulegone is an

99% ee PPh2 Other enantioselectivereactions. Severalasymmetricreactionsworth mcntioning are the cu-catalyzeilallylic oxidationin the prcsenccof l05,r1r l06,r1ror l07rr5with loxiclationof sulfides(/-BuooH Tirvl in the prescnceof a 4,4'-dimer of butyl perbenzoate, the reductiveaminationby chiral t-butylsulfinamidc,rrr B-aromatic3-hydroxyestrane,rr('the with ol'phcnols C-arylation gfyoxylate ene reactionpromotedby Yb(OTf )r andent-73.2tE aryllcad reagcntsundcr the influenceof brucine,rr"and the C-H bond inscrtion by Rh-

PPh2

\/ ro;--

----\L-N'

Pd F"CCOO' \

d

,

P

1. (108)

(1Ull

carbenoids.:lo

MeO

H P h NJ VOH

*4-on H P h (105)

A Y2

rt

H".|_N (^\"" i3

(106)

(107)

Enantioselectivecyclization of carbanrtx -rn lead to cis- or trans-1,2-disubstitured c t'232 ' BuLi-( - )- sparteine.23

Chiral auxiliariesand catalysts

\

H

'

= -.1

a;.-Kn1,Lp[

NHAc +

:

I n l -\---NH

-.,,^\ rtl

/

..

99% ee

119

Heterocyclic analoguesof BINAP, such as the bis(benzothiophene)108 as well as the have been prepared 2,2',5,5'-tetramethyl-4,4'-bis(diphenylphosphino)-3,3'-bithiophene, and testedin the Heck reaction.22rIncorporation of a chiral o-(N,N-dimethylamino)phenylsulfinyl group to a double bond elicits enantioselectivity at the B-carbon during the intramolecular Heck reaction.222Optically active 5-arylcyclopenten-l-yl r-butyl sulfoxides are produced from (R)-1-r-butylsulfinylcyclopentene.223 Palladacycle (109) and its analogues induce chirality of N-allylalkanamides during rearrangement of allylic imidates.22aFor a synthesis of a-branched chiral 4-alkenethioamides, it is convenient to allylate thioamides of (*)-trans-2,5-diphenylpyrrolidine.22sThis processinvolves a thio-Claisen rearrangement. Enantioselectivedeprotonation of ketones is achieved by using a homochiral magneOn the other hand, 110 is excellentfor prosium bis[N-benzyt-N-(ct-phenethyl)]amide.226

BF;

tonationof enolates.227 Access to bicyclic enones from 1,6-enynesby the Pauson-Khand method is rendered enantioselective by installing a chiral f-butylsulfinyl group at C-1.228Cyclization of a-benzylidene-aroylacetamidesto furnish 3-arylindanones is subject to 1,5-asymmetric

lO{

-t'

* -.-Rh

NHAc

--,,l--l

induction when the amide moiety is derived from a bulky 4-substitulted oxazolidin-2one.22eChiral ligands for the Pauson-Khand reaction have also been studied. Phosphineborane(1L1) derivedfrom (+)-pulegone is an example.2r0

S

99% ee SiMer PPh2 u

)l

r l_

nctric rcactionsworth mentioning , , r l 0 5 . r r r1 0 6 , : r o 1 r l 0 7 r r 5w i t h / rn thc prcscnccof a 4,4'-dimcr of the hr chirall-butylsulfinamidc,rrT i' phenols with ol' 7-1.r C'-arylation j rhr-C-H

hond inscrtionbY Rh-

PPh2

(108)

\/ .o>__-+_-'-\{-N' -Y F"ccoo'Pd>r i"

yr--f

R,

t

ll

) - COOR'

\-'l-N H

Pocr,-PhN(cHo)N/e- a)-\ ' Kll ll N / C P B A - T S O H /C H 2 C | ,

-

cooR'

\."-N H

80-90% .rnd the title reagent are good -:

tff)0).

::r'rat€dfrom the title reagenton lrto substituted tetrahydro:.iris tlr. '.'ihle when the traPPingagents B

) l { . . + - t i 7 r 1 5 , 8 6 ;1 6 , 8 0 - 8 3 ;L 7 ' , . .-.c' oxidationsserveto complete :r, -'- tr) nitriles,2and B-aminoesters

OTBS

I /\ Ct't 63% (93%ee)

(e'g'' -78') when Epoxidation.e Alkenes arc epoxidized at low temperatures catalyzcdby (MeCN )aCuPF6. with oso-, Dihydroxylation,l0 The conventionalmethod of alkenedihydroxylation reagent latter the that such modificd becn (NMO) has anclN-mcthylmorpholincN-oxide MCPBA' of equiv l 4 and N-methyhnorpholine is replaccclby substoichiometric T S 1299(2000)' T'' Fukuyarna' r1'okuyama, T.,Amano,A', Yamashita' tl., Kuboyama, J M IA l0' ll45 rDicz.Il.. Fernandcz, E, Pareja'C'' Prieto'A ' Lassaletta' R., Martin-Zamora, ( I 999). 'Davics. C.A.P,Smith'A'D ' Smyth'G'D' ?"A1l' 2437(2000)' S.G.,Smcthulst, rCtrrbin, P.'fL 40,23l9 ( 1999)' C.,Metzner, Fl,Alayrac, 'Ma. D..Xia.C..Tian,H. TL 40'8915( 1999)' "Kotsuki.H.,Arimura,K., Araki,T., Shinohara, T SL462( 1999)' 'Wattenbach, U' SL 303( 1999)' C., Maurer,M., Frauenrath' 'llickman,Z'.,Sturino'C.F-., N ?"L41' 8217(2000)' Lachance, 'Andrus. B.W.fL 41, l0l3 (2000)' M.8.,Poehlein, 'ucrgstad, J -E'JOC64.2s45( 1999)' Biickvall, K.. Piet'J.J.N., chloride' I Chloro(phenylthio)methylene]dimethylammonium reagcnt' this by converted are Alkyl halides.t Primary alcohols unprotected atl'ecting without yields in excellent lMc:N:C(Cl)sPhlcl, to the chlorides obtaincd' \ccondaryhydroxyl groups.In the presenceof BuaNBr' the bromidesare C' TL 4l' 6049(2000)' A., Mioskowski' Gomez,L., Gellibert,F'.,Wagncr, 19,95-96; 20' 108 .v-chlorosuccinimideNcs. 13, 79-80; 15, 86-88; 18' 101-102; induced to decompose are (E)-Bromoalkenes.t (Z)-l-Dialkylbora-l-bromoalkenes N, N-dimethyllbrmamide, by is exerted effect \rcreoselectivelyby NCS. A specialsolvent .rndis superiorto DMSO.

132

Chlorosulfonyl isocyanate

a f-a'\-

o

O=C=N-SO2C|

A 'n-cr

Ph

|

\,{

\7

\/

OMe

P

KoH - Na?so3

o THF - D[,,1F

'/-[

[3 + 2]Cycloaddition. l-Lactams arr particular interest is the formation of a I 1 precursorof peduncularine.

82o/o

Methylthiomethylation.2 The Corey-Kim reagent (NCS-dimethyl sulfide) induces cyclization of tryptamine derivatives while introducing a methylthiomethyl group at C-3. An efficientroute to physostigmineis basedon this process.

MeO

(

,!-o""t

\ '-1N) / / t

H

l

'cooMe i

NHCooMe

MeO 1F

Ncs- N/ezs

_SMe

'

(,, ,>.-f-^.

i - p r , N E t \ - - ( \ ) - C O O M e

'ufN

crrci, n

H

o/

H H boovr" Me.

o NH\O\

C,>l-\ -*t^. M6H

Me

physostigmine

Chlorination.s propanol.

>ie

O=C=N-SO2C|

Anilides and deactivated anilines are chlorinated with NCS*2-

Biaryls,a Homocouplingof ArZnI employs NCS as an oxidant in the presenceof a Pd(0) catalyst.Yields are good. lHoshi,M., Shirakawa, K.TL41,2595(2000). 2Kawahara, M., Nishida,A., Nakagawa, M. OL2,675 (2000). rZanka,A., Kubota,A. Sa 1984(1999). aHossain, K.M.,Shibata, T.,Takagi,K. Sa t 137(2000).

Chlorosulfonyl isocyanate. 13, 80-8 1; 18, 102 N-Allyl carbamates.t Preparation of the carbamates from allyl ethers may incur 1.3-transoosition.

iKim,J.D.,Lee,M.H.,Lee,M.J.,Jung,YH. IL I rlsaka,M., Williard,P.G.,Nakamura,E. 8CS/ 7l 'Roberson, C.W.,Woerpel, K.A. OL2,62l rlffi)

Chloro(triphenylphosphine)gold(I). Hexaalkylditins.' Oxidative dimenza (PhrP)AuCl.

Reductive silylations.: In the presen imines undergoreductive silylation b1 a h1 undertheseconditions.

'lto, H.,Yajima,T.,Tateiwa, J.,Hosomi,A. ft I rlto, H.,Yajima,T.,Tateiwa, J.,Hosomi,A. C(-9€

Chlorotris(triphenylphosphine)rhodiun I Allylic alkylations.t 3 Highly regros nucleophiles (phenolates,sulfonamides. and also possible with the Rh catalyst modrha

seems to play an important role in the dr branched allylic ethers; thus, reaction wirh I the product yields are low The best compru

Chlorotris(triphenylphosphine)rhodium(I)

O=C=N-SO,C|

Ph, y'., v

,OMe

'nn

:

> KOH - Na2SO3

\7

\./

NHCOOMe

(2.7 c"

1)

[3 + 2]Cycloaddition. ^y-Lactams are formed on reaction with allylsilanes.2 Of particular interest is the formation of a bridged ring representative that serves as a precursorof peduncularine.3

82Yo

: '\CS-dimethyl sulfide) induces ., nrc'thylthiomethylgroup at C-3.

Ph COOMe

\

/-\

rsiR3

O=C=N-SO2C|;

HN/\

,nlzt'a:)

oN 62To

!

booH,t"

peduncularine

l l,t,-

\\

..- ^ o \

Kim, J.D.,Lee,M.H.,Lee,M.J.,Jung,yH. fL 41,50:13 (2000). rlsaka,M., Williard,p.G., Nakamura, E. BCSJ72,2115(1ggg). tRoberson, C.W.,Woerpel,K.A. OL 2, 621(2000\.

I

/m \r-r-i-( M ; H

M e

physostigmine

. arc chlorinated with NCS-2g ' .

\

1. an oxidant in the presenceof a

!:- , r:ttcS from allyl ethers may incur

Chloro(triphenylphosphine)gold(I). Hexaalkylditins.t (PhrP)AuCl.

oxidative dimerization of RjSnH (e.g., BujsnH) is mediated by

Reductive silyrations.2 In the presence of (phjp)Aucl and Burp, aldehydes and imines undergo reductive silylation by a hydrosilane (phMe2SiH). Ketones do not react undertheseconditions. rlto,H.,yajima, T.,Tateiwa, J.,Hosomi,A. TL 40,7g07(lggg). rlto,H.,yajima, T.,Tateiwa, J.,Hosomi,A. CC 9S1(2000). Chlorotris(triphenylphosphine)rhodium(I). 19, 96_98; 20, 10g_l 09 Allylic alkylafions.t 3 Highly regioselective alkylation of both hard and soft nucleophiles (phenolates,sulfonamides, and phenylsulfonylacetic esters, respectively) is also possible with the Rh catalyst modified by the added (Meo\p. The countercation seems to play an important role in the displacement with alkali phenolates to afford branchedallylic ethers; thus, reaction with Li salts shows the highest regioselectrvity but the product yields are low The best compromise is to use Na phenolates.

Chlorotris(triptaf 134

Chlomtris(triphenylphosphine)rhodium(I)

'nlo)

'nY\ Ph.

ocooMe. a-)-/

(Ph3P)3RhCi

Y\ Mo'V

.t\t2

-^--J

--L/

(NIeO)3P THF

(97o/o)

M = Li

(11o/o)

Chlorotris(triphenylphosphine)rhodin mt I r Hydroacylation. ct-Cleavageof a phen (after elimination of styrene) to an alkene c

2 0 : 1 1 2 : 1 3 8 : 1

M = Na (97olo) M = K

o"\"'

switulski,B., Stengel, T. ACIEE3S'2426(lv)9t 6WendetP.A.,Dyckman,A.J., Husfeld,C.O.. Kid ( l e9e). TVogels, M.P, Westcc* C.M.,Hayes,P.G.,Shaver,

imine formation of the ketone with 2-amr speciescombines with the alkene and then un

Reformatsky-type reaction.a This procedure involves treatment of the ct-bromo esterswith Et2Zn and the Rh(I) complex. This mild and eflicient reaction is applicable to both inter- and intramolecular versions. Cycloadttitions. Substituted indolines are formed from N-functionalized l-alkynyl amides via a 12 +2 +2lcycloaddition process.5A study on the regioselectivityand stereoselectivityof the [5 + 2]cycloaddition promoted by the Wilkinson catalyst together

rY i

o Ph,/\-A

l

l

\"4n..

* R,\

(Ph3P)3RhC PhMe

.r

with AgOTf has beendelineated.6

||I "'

/--'r\ i l

(PhrP)3RhCl (

+ l l l + N-#I

S

'ru-\Z

Further extension of the method resullr r des and alkenes2and, in the case of an aro Imines of aryl ketones undergo o-alkylation

|

PhMe20'

TJ

TS

91Yo

1'\'/

Addition to vinyl aminopropyl ethers.l Boranes add to the double bond in the antiMarkovnikov sense under the influence of the Rh catalyst. However, intramolecular hydroamination to give tetrahydro-2-methyloxazine occurs in the presence of Pd or Pt complexes.

* nAH

\tR'

"t,

o (Ph3P)3Rhcr

H,Nvo-\

ll \*A

o

* f\-- tr J'-to'\ | to,,-

^\

PY-

H'NYo'\-d-o{

tto.,At l ll + \/

(

v.R'

NBn

1]X

lEvans, P A., Leahy, D.K. "/ACS122,5Ol2 (2000). 2Evans.P A., Robinson,J.E.,Nelson,J.D. .IACSl2l,6'761 (1999). 3Evans,P.A.,Kennedy,LJ. OL2,2213 (2000). lKanai, K., Wakabayashi,H., Honda, T. OL2,2549 (2OOO)-

* \-R' ri,^"1,,^\/

J u n ,C . - H . ,L e e ,H . J A C S1 2 1 ,8 8 0 ( 1 9 9 9 ) . Jun, C.-H., Lee, D.-Y., Lee, H., Hong' J.-8. ACri J u n .C . - H . ,H o n g ,J . - B . ,K i m , Y - H . ' C h u n g .K - l

Chlorotris(triphenylphosphine)rhodium(If 2-Amino-3-picoline

=^-.2-.,

Ph:Z\

,\-.l,J

.

l-z

,^-,,\,

-,

20

,

o^.,,lj

rl-:

5witulski,B., Stengel,T. ACIEE 38,2426(1999). 6Wender, P.A.,Dyckman,A.J., Husfeld,C.O.,Kadereit,D., Love,J.A., Rieck,H. IACS l2l, 10442 (1999). ?Vogels, C.M.,Hayes,P.G.,Shaver, M.P.,Westcott, S.A.CC 51 (2000). Chlorotris(triphenylphosphine)rhodium(I)-2-Amino-3-picoline. Hydroacylation. ct-Cleavageof a phenylethyl ketone and delivery of the acyl group (after elimination of styrene) to an alkene occurs around Rh. The reaction starts from

.. 'l

1 2 : 1 3 8 : 1

trl

imine formation of the ketone with 2-amino-3-picoline. After cleavage, the [Rh]-H speciescombines with the alkene and then undergoesreductive elimination.'

,,]\cs treatment of the a-bromo : jllicient reactionis applicableto

/Y i

(:

r rr()rnN-functionalizedl-alkynyl .:uJr on the regioselectivityand .r the Wilkinson catalysttogether

/--/\ i l ^,'\,/)

l

-S

*

a\a

?: , . :Jtl to the double bond in the anti-.rr]lvst. However, intramolecular i r., -,rrs in the presenceof Pd or Pt

(^A**,

(J

^,\.. K

H

+ \-R'

R=Bu 98%

o

R'Jl-.--^R'

PhcooH, PhNH2

z/-\Y/

ll

9Y

(Ph3P)3Rhcl

Phl\,le a

IJ

'o"\

--* n-\A

-,P6fi-

n\

Ph"\*

91%

-- ^rn

ltr. l L*^-Al

l

\rA"n,

o

Further extension of the method results in a direct synthesis of ketones from aldehydes and alkenes2and, in the case of an aromatic aldehyde, o-substituted aryl ketones.3 Imines of aryl ketones undergo o-alkylation.

l

1"- r.-ruYo-\-d.o{-

r35

/VH ll

v

|

+ \/,R'

i l t \*- *", (Ph3P)3RhCl '170' BUNH2

o ll

rr*a-

R'

\-7

-.-.AR,

o

f--A\z\.,.."rJun,C.-H., Lee,H. JACS 121, 880 (1999). 2Jun,C.-H., Lee, D.-Y., Lee, H., Hong, I.-8. ACIEE39,3070 (2000). rJun,C.-H., Hong, J.-B., Kim, Y.-H., Chung, K.-Y. ACIEE 39, 3440 (2000)

t(

136

Chromiurn-carbene

complexes

Chromium-carbenecomplexes.13, 82-83; 14,91-93: 15, 93-95; 16, 88-92;17, 80-84;L8,103-104; 19,98-101;20, I 10-l 11 RearrangemenL Allyloxy(aryl)carbenecomplexesare convertedto allyl aryl ketones on Pd(0)catalysis.l

/-\

\

(Ph3p)4pd

)

0

-Ecrrcot^

BuLi :

(

p \-

PhcHo BF3'OEI2

\-J

P

dienolates,respectivelY.o

co/cH2cr2

r

t-O

Reductive cyclization of chromrr the carbon chain leads to bicyclic b are assembled when conjugated c:

LO

Ic4co1u

(

. 71o/o

I

./"'

t

Cr(CO)

t l \oA *

Cycloadditions. Pyrolysis of O-alkynyl cyclopropylcarbene complexes generates fused cyclopentenones. This transformation has been exploited in a synthesis of a vitamin Dj synthon.2

OMe

. rc>Ac,tco): t t l \-/ OMe I

,Ac(co), tl vitaminD3 intermediate

*

L

R2

Highly functionalized diaryl etl 3-Substituted1,2-naphthoquinones are formed by an intramolecularreactionof o-alkenylarylcarbenecomplexes.With an electron-richaromaticnucleus,the photoinducedbenzannulation is sluggish.The useof r-butyl isocyanideinsteadof CO circumventssuchproblems.l

tutedFischercarbenecomplexesutt

ll\_x OMe

o !c4cor /

t-Bu-NC/ THF ; +

cAN

^t{

R

Meo

'

R

MeO 82Yo

A chromane synthesis is readily accomplished from pentacarbonyltetrahydropyranylidenechromium via alkylidenation and photoinduced cycloaddition.a

Dikctones. Pd(0)-catalyzed c and AII-CO give a-diketones.' '*h to furnish 1,4-diketones.'

Chmmiumi)^t'^ A"',^-" R = C6H17 93%

CrCl2/ DN,IF

cHo

:) Ph

j}-x' Ph' \_, 54Yo

ChromiumflIl) chloride

rBaati, R., Gouverneur,V., Mioskowski, C. JOC 65,1235 (2000). 2Baati,R., Valleix, A., Mioskowski, C., Barma, D.K., Falck, l.R. OL2' 485 (2000). 3Falck, J.R., Barma, D.K., Mioskowski, C. TL 40,2091 (1999). aTakai,K., Hikasa,S., Ichiguchi,T., Surnino,N. Sf 1769 (1999). sMolander.G.A.. Rtjnn. M. JOC 64,5183 (1999). 6Toratsu,C., Fujii, T., Suzuki, T., Takai, K. ACIEE 39,2'125 (2000).

ChromiumflI) chloride-nickel(Il) halide. 14,97-98;15,96-9"1;17,86; 18, 105; 19' 102:20.1l3-l 14 Alkenylation of aldehydes. Alkenylchromium(IlD species are generated by the electrochemical reaction of CClr-NiBr, with alkenyl bromides in DMF. Their reaction with ArCHO in the presenceof MerSiCl gives silyl ethers of allylic alcohols.r Instead of electrochemical reduction, aluminum can be employed as the electron source.2 An alternativepromoter is tetrakis(dimethylamino)ethylene.r IKuroboshi, H.' Torii'S.Sa 69 (1999). M., Kishimoto,S.,Tanaka, M., Tanaka, 2Kuroboshi, M., Tanaka,M., Kishimoto,S.,Goto,K., Tanaka'H., Torii, S. ?L 40' 2785(1999)' sKuroboshi. M.. Tanaka,M., Kishimoto,S.,Goto,K., Mochizuki,M., Tanaka'H. TL 4l' 81 (2000)'

Chromium(Ill) chloride. Benzhydrols and diaryI kctones.l Mediation of the ArZnI reaction with ArCHO by CrClr leads to benzhydrols. In the caseofo-zinciobenzoic esters,phthalides are formed. When PhCHO (or any other ArCHO) is added at the termination of the reaction as a hydrogen acceptor to the chromium(Ill) diarylmethanoates,an oppenauer oxidation oc-

'Takai, K., Ichiguchi. T.. Hika'a- S rTakai,K., Hikasa.S.. Ichigu.-hr-T ' ' A u g e , G i l , R . ' K a l s e l .S ' I L l . J..

Chromium(IV) oxide.20. I l{ D Reaction of acetaknamaldehyde) are hydrohzed aliphatic aldehYdesso generata

:Ko,K.-Y.,Park,S.T.IL {0. dll5 t

Chromium(Vl) oxideil-drc Aryliodin e(I I I ) dic h loridc CrO3-HCl in aq HOAc at roott

:Kazmierczak, P.,Skulski.L.. Oba

Chromium(Vl) oxidePeriod Benzylic oxidotion.: Th responding acids and dra4

temperaturein MeCN. Benzli phthalide and 3,4-dihYdrotsan S. OL 1' 2129tlV)9' Yamazaki,

curs and the products are diaryl ketones.

CrCl3

Ar-Znl

+ A/CHO

+

I

oc/il'l

PhCHO +

lo,"Aorl

? RrARr

Chromium Peroxide. Oxidation of alcohok. benzylicalcohols.

A ,lCl M.M., KeYvan. Lakouraj,

70-80o/o

Allylations.2 Allylating agents prepared from allyl halides, CrClr, NiBrz, and MerSiCl react with carbonyl compounds, provided that tetrakis(dimethylamino)ethylene is usedas electronsource. Zn, and (E)-Iodoalkenes. Aldehydes are homologated with iodoform, (thf)icclr' MerSiCl in dioxane to afford (E)-iodoalkenes3at room temperature. On replacing Zn with Mn the reactionproductsare (D-alkenylsilanes.o Conjugate additinns.s Organochromium reagents derived from halides such as BnBr and crClr-Mn add to acrylonitrile (water is an additive in the reaction medium). rOgawa, T.,Takagi,K. JOC 65,l03l (2000)' Y, Saiga,A., Mori,M., Shibata, 2Kuroboshi. M.. Goto.K., Mochizuki,M., Thnaka,H. SL 1930(1999).

Cobalt. Pauson-Khand reactb* rn refluxing toluene in the P heterogeneouscatalYst for th carbon,which can be usedat I

Kim, S.-W.,Son,S.U.,Lre. S I :Son,S.U.,Lee,S.I.,Chung. \' K Cobalt([) bromide. 19' l0r Coniugate additions. halides to activatedalkenes'

CobaltflI) bromide

rTakai, K., Ichiguchi, T., Hikasa, S. SL 1268 (1999). lTakai, K., Hikasa,S., Ichiguchi,T., Sumino, N. SI, 1769 (1999). sAuge, J., Gii, R., Kalsey, S. ZL 40, 6'1(1999).

I t, - . t t ) t . 2 . - 1 8 5( 2 0 0 0 ) . tr. t$... ! _ . .

9. I 5. q6-97; 17, 86; L8' 105;19, n i.. .pccies are generatedbY the tr. -: :nrdesin DMF. Their reaction cir -:. r,l allylic alcohols.rInsteadof p. .,.: .r: the electron source.2An lc:., r u. :l'

. '1.69( 1999). ii f,rnr.S. ZL40, 2'185(1999). .. \1..Tanaka, H. fL 41,8l (2000).

c: : - \rZnl reactionwith ArCHO bY ri.. - c':tcrS.phthalidesare formed' u ::.- :cnninationof the reactionas a !-1: .:1... an Oppenaueroxidation oc-

:-_ - H "^

rKo.K.-Y..Park,S.T.TL40,6025(1999). Chromium(Vl) oxide-hydrochloric acid. Arytiodine(Ill) dichlorides.t oxidative chlorination of ArI is completed by using CrO:-HCl in aq HOAc at room temperature' rKazmierczak, P, Skulski,L., Obeid,N.,/CR(S)64 (1999).

Chromium(Vl) oxide-periodic acid. BenzXlic oxidation.t This combination oxidizes substituted toluenes to the corresponding acids and diarylmethanes (including fluorene) into ketones at room temperature in MeCN. Benzyl ethers such as phthalan and isochroman are converted to phthalide and 3,4-dihydroisocoumarin in quantitative yield' rYamazaki, S. OL 1, 2129(1999).

Chromium peroxide. oxidation of alcohols.t benzylic alcohols.

- l ol Ar

A'

Chromium(IV) oxide. 20, ll4 Reaction of acetals.t Dimethyl acetals of aromatic aldehydes (including cinnamaldehyde) are hydrolyzed in aqueous chloroform with CrO, as catalyst. However, aliphatic aldehydesso generatedundergo oxidation to afford carboxylic acids.

Ar'

Polymer-supported cro.

selectively oxidizes allylic and

rLakouraj,M.M., Keyvan,A. JCR(S)206(1999).

70-80Yo

Ir: ,.r1 halides,CrCl., NiBrr, and I ::, r-'trakis(dimethylamino)ethylene r: .. ::'. r(xloforrn, (thf)',CrClr, Zn, and | : ::r (cmperature. On rePlacing Zn rg: . Jcnved from halides such as lr. .,.:.j:tl\!-in the reactionmedium). tr, n5 .'t.rlt1000). . .:

.199).

Cobalt. pauson-Khand reaction. Cobalt is depositedby decomposingdicobalt octacarbonyl in refluxing toluene in the presenceof mesoporous silica. The substanceis active as a heterogeneouscatalyst for the Pauson-Khand reaction.r A related catalyst is cobalt-oncarbon,which can be usedat least l0 times with yields maintaining at the 95Vo\evel.1 rKim,S.-W.,Son,S.U.,Lee,S.1.,Hyeon,T., Chung,Y.K.JACS122'1550(2000)' :Son,S.U.,Lee,S.1.,Chung,Y.K.ACIEE39,4158(2000). Cobalt([) bromide. 19, lO4 Conjugate additions.t Cobalt bromide catalyzes electrochemical addition of aryl halidesto activatedalkenes.

Copper(Il) acetate rGomes,P.,Gosmini, C., Nedelec,J.-Y.,Perichon, I. TL 41.3385 (2000).

Cobalt(fl) chloride. 14,99;15,97-98;18,107-108; 19, 104-105;20, I t5-t t6; Hydrosilylation.t A new catalyst for regioselective hydrosilylation of acrylonitrile is CoCl2. Only the B-silylated nitriles are obtained. a-Hydroxy-pketoesters.2 The hydroxylation of B-ketoesters with molecular oxygen is carried out under neutral conditions. rChauhan, M., Chauhan, B.P.S., Boudjouk ,P. TL 40,4127(1999). 2Baucherel, X., Levoirier, E.,Uziel,J.,Juge,S. TL 41,1385(2000). CobaltflID fluoride. Quinones,t Hydroquinone dimethyl ethers undergo oxidative demethylation on contact with CoF.. The reagentis comparable to AgO or CAN in efficiency. Fluorination,2 Fluorination of unsaturatedcompounds with CoF., is carried out in a stainless steel vessel from -196" to room temperature. The method transforms methyl trifluorovinyl ether to methyl pentafluoroethyl ether in 7O% yield. rTomatsu, A., Takemura, S., Hashimoto,K., Nakata,M. SL 1474(1999). 2Tamura, M., Takubo,S.,Quan,H., Sekiya,A. SL 343(2O}Ltt.

rKooti,M., Esm-Hosseini, M. SC30.651(2000). Copper(Il) acetate.18, 109-l l0; 19, 106; 20, ll'7 Arylations. Copper(Il) acetate catalyzes the reaction of arylboronic acids with thiolsr and of amineswith hypervalentarylsiloxanes.2 4-Substitutedimidazolesreactwith aryllead(IV) reagents (in dichloromethane at room temperature) to afford N-l arylated derivativesregioselectivelyundercatalysisof Cu(OAc)r.l Radical cyclizations. Copper(Il) acetate has a great influence on the Ni HOAc promoted5-endo and5-exocyclizations.a

o

i%*,3,yr.Aaiq" additive: NaOAc,i-PrOH Cu(OAc)2,t-BuOH

rHerradura, P.S.,Pendola, K.A.,Guy.R.K.OI2lam, P.Y. S.,Deudon,S.,Averell.K.tt.. t:. l (2000). 3Blliott,G.I.,Konopelski, I.P.OL 2,3055rlfi oCassayre, J.,Dauge,D.,Zard,S.Z.Sl {71 rl{l 5Nikal.1e, M.D.,Ali, I.s., Dewkar,G.K..Sudat 6Sammakia, T.,Jacobs, J.S.fZ 40,2685r 1999

Copper(I) bromide. Cyclizatian.t Cyclization of l'-allr room temperature involves atom transfer 2,2'-brpyrtdine.

Cobalt([I) halochromate, arnmine complexes. Oxidation.' The cobalt complexes are mild and efficient oxidants with which alcoholsare oxidized to carbonylcompounds.

o

Aroylfurmic aci .s l-Aryl-l-nrtn HOAc-MeOH at 90o to afford the ketomr only give the correspondingmethyl ether: Cleavage of picolinic acid esten.' protocol using picolinic acid as the nrx alcohols are readily recovered,that is. aric

rClark,A.J.,Duncalf,D.J.,Filik, R.P..Hadtlr ( I 999).

Copper(Il) bromide. 14, 100; 15, l0O: lt 4-H alo -5 -hy dro xypy rr ol- 2 (5H lonct. (slightly less efficiently, CuCl:) furnrsh followed by oxidation at C-5 when the all

P

,R'

R

:"{

'coruxn

R' CONHR"

Insertion into silacyclopropnct-' silacyclopropanes with methyl formate r selectivity is totally switched from one of r

Copper(Il) bromide

- rxtr.

lri

9. 1r-

- : I 0 5 : 2 0 , 1 1 5 - 11 6 ; . Jrosilylation of acrylonitrile

o:

.r-k!-toesterswith molecular

!'.

!r,,

, r i t l a t i v ed e m e t h Y l a t i oonn L'x | \\ rn efficiency. r .. :. \\ rth CoFsis carriedout in a ri I ::. rnethodtransformsmethYl . rr'ld.

Aroylfurmic acids.s l-Aryl-2-nitroethanols are oxidized by Cu(OAc)2 in HOAc-MeOH at 90" to afford the ketoacids.Nitroaldols derived from aliphatic aldehydes only give the correspondingmethyl ethers under theseconditions. Cleavage of picolinic acid esters.6 One advantage of the Mitsunobu reaction protocol using picolinic acid as the nucleophile is that the configurationally inverted alcohols are readily recovered,that is, after treatment with Cu(OAc)2-MeOH. rHenadura, K.A.,Guy,R.K. OL2,2019(2000). P.S.,Pendola, 2lam, P.Y. S.,Deudon,S.,Averell,K.M., Li, R., He,Y, DeShong, P.,Clark,C'G.JACS122'7600 (2000). rElliott,G.I.,Konopelski, J.P.oL2,3055 (2000). aCassayre, J.,Dauge,D.,Zad,S.Z. SL47l (2000). sNikalje,M.D.,Ali, I.S.,Dewkar,G.K.,Sudalai, A . rL 41,959(2000). 6Sammakia, J.S.fL40,2685 (1999). T.,Jacobs,

Copper(I) bromide. cyclization.t cyclization of N-atlyl cr-bromoamides induced by ligated cuBr at room temperature involves atom transfer. 2-Pyridylformaldimines are better ligands than 2,2' -bipyrrdrne. lClark,A.J.,Duncalf,D.J.,Filik, R.P.,Haddleton, D.M, Thomas,G.H.,Wongtap,H. TL 40' 3807 ( 1999).

licicnt oxidants with which

t.:-

.:\ f:'

t -

:r ol arylboronic acids with '..rrtutedimidazolesreactwith :.lturc) to afford N-l arYlated

Copper(Il) bromide. 14, 100;15, 100;18' 111;19, 106 Treatment of 2,3-alleneamides with CuBrt 4-Hala-5-hydroxypynol-2(5H)-ones.t (slightly less efficiently, CuCl2) furnishes the title compounds. Halolactamizationis followed by oxidation at C-5 when the allenyl moiety is not fully substituted.

X

R

R'

R

CONHR'

P

,R'

. rnUuenceon the Ni-HOAc

R

X=Cl,Br

X.,Ao

R ' ) R" X

:,-:Q+"

:C={

CONHR"

'

R>< R

'

R>< X=Cl,Br

,.oxfAo

'

\-,

c k

r-li ' 3uOH

Insertion into silacyclopropanes.2 Remarkably regioselective reactions of silacyclopropanes with methyl formate are mediated by CuBr2 and ZnBr2. The regioselectivity is totally switched from one ofthese two salts to the other.

144

Copper(I)chloride

\Z

CuBr2

!r,k

o * \or,t" H

t ||

-

L \4 I tnr,,,

\ / --FSi-O /

I

|

Yt

\

SnMe3

OMe

- -

70o/o

*p,_o,

-l*o""

Coupling of zirconacyclopentadter sults in cyclooclatetraenes.?

7$Yo

r--dx

O rMa.S..Xie,H. OL2,3801(2000). rFranz,A.K., Woerpel,K A. ACIEE39 4295(2000)' Copper(I) chloride. 13, 85; 15, 101; 18, ll2-ll3; 19, 107-108; 20, ll8-120 of alkyl halides Oxid.ations. Carbonyl compounds are obtained from autoxidation (15 8l-997o\'l examples' and tosylatespromotedby CuCt on Kieselguhr Sterically coupling reactions. The Stille coupling is accelerated by cuCl. cucl in (Phr)+Pd, Licl, of congested substrares are readily coupled in the presence DMSO.2 stannanes Allylfurans and allylthiophenes can be synthesizedfrom the corresponding to l-chloroalkynes and by coupling with allyl halides.r The coupling of alkynylsilanes Benas C--{'a such groups furnish conjugated diynes tolerates many sensitivefunctional zotropylidenes and benzotroponeszue accessiblefrom the reaction of zirconacyclopentadieneswith 2-iodobenzylhalide and 2-iodobenzoylhalide,respectively.5

5

I

ZrCp2

y=e;H,H

and

h

CuCI-DCC via pseudoureaintermedtar Aryl radicals.e A synthetic appl CuCl is radical generation at an c-pos aminobenzoyl) derivatives in the prer which the ct-position becomeschlorina the nascentaryl radicalsis evident.

'r\r^*/\

\4,

I

Silvlq

Tertiary

Dehydration.8

I

t\r-

I

SiMe3

NH2 O l l l

Y i R 'u''z .-.-A^, co,z,\''

SaMe

SiMe3

l--s -)

^

4\)

TBSO.,,/ -O

-U

Hc

'-''-

,

r-

2,2'-Bridgedbiaryls are readily obtained from short-chain 1,to-bis(2-trimethylstannylaryl)alkanesby treatment with CuCl in DMF at room temperature'6

Pinacolatoboration.tt) Hydrotrn effected with bis(pinacolato)diboron r borylcopper species is involved in t nucelophile toward allylic halides and I

Copper(I) chloride

Etooc .cooEt

\)Z

'fo'"

_-Fsi-o

SnMe3

-\

R

70%

Y

R

R = OMe

I

{

62%

by cuCl rewith (Z,Z)-1,4-diiodo-1,3-dienes coupling of zirconacyclopentadienes in cyclooctatetraenes.t sults

SiMe3

/v\

O

-

I

ZrCP2 + SiMe3

SiMe3

MesSi

,SiMe3

Aa" "'"'. ",l-h"

| ',t2--/

i rHF Dl\'lPU

/-\

|

Me3Si

SiMe3

SiMe3

56% ). . '- 108:20,118-120 t :: ::t rutoxidation of alkYl halides r : : : :: - . r . .8 | - 9 9 7 a ) . 1 i ,-,.'lcrated bY CuCl' StericallY R-r:r'e t)f (Phi)4Pd,LiCl, CuCl in N :: r1rthe corresPondingstannanes [, r:..rlanes and l-chloroalkynesto n.:. nll grouPssuch as C-0'4 Ben-

Dehydration.s

Tertiary

and

alcohols

benzylic

undergo dehydration

with

CuC1-DCC via pseudoureaintermediates. Aryl radicals,e A synthetic application of the arenediazonium ion reduction by CuCl is radical generation at an ct-position of amines. Thus, diazotization of the N-(2aminobenzoyl) derivatives in the presence of CuCl in MeOH leads to benzamides in which the ct-position becomeschlorinated and/or methoxylated. Hydrogen abstractionby the nascentaryl radicalsis evident.

n: :::. rcactionof zirconacyclopentau. :.::. rcspectivelY.5

o Hcr.NaNo2 'iO+-\

"*;;- \2;;.?" 2

3

-

r

|

X = C l 2 6 o / o+ X = O M e 3 0 %

h : .hein 1,to-bis(2-trimethylstanny)c'.:J:llPerature.6

Pinacolatoboration.to Hydroboration of 1-alkynesto give 2-pinacolato-l-alkenes is effected with bis(pinacolato)diboron in the presence of CuCl and KOAc. Perhaps a borylcopper species is involved in the reaction. The same reagent is useful as a nucelophile toward allylic halides and Michael acceptors.

Copper(Il) chloride

..-l-".^ .u",-Licr-KoAc

. --*;4-o'-'o-l--lll

-f

".

pf

|

,*

-1-o'\

rHashemi,M.M., Beni, YA. JCR(S).434(1999). 2Han,X., Stoltz,B.M., Corey,E.J.JACS 121' 7600 (1999). 3Nudelman,N.S., Cano, C. SL 1942 (1999). lNishihara, Y., Ikegashira, K., Hirabayashi' K., Ando, J'-I', Mori' A, Hiyama' T' JOC 65' l'780 (2000). 5Takahashi, T., Sun,W.-H., Duan'Z', Shen,B. OL2,ll9'7 (2000)' 6Piers.E.. Yee, J.G.K.,Gladstone,P.L.OL2,481 (2000). TYamamoto.Y., Ohno, T., Itoh, K. CC 1543 (1999)' 8Majetich, G., Hicks, R., Okha' F. NIC 23' 129 (1999)' eHan, G., LePorte, M.G., Folmer, J.J.,Wemer, K.M., Weinreb, S'M ACIEE 39,23'l (20O0): Han' G'' (1996)' LePorte.M.G., Mclntosh, M.C., Weinreb,S.M., Parvez,M' JOC 6l' 9483 r0Takahashi,K., Ishiyama, T., Miyaura, N. CL 982 (2000).

Copper(Il) chloride. 14, 100;18, 113-114;19' 108;20,120 Halolactonization.t Allenic acids give p-halo-^y-butenolideson reaction with cuX2 (X: Cl, Br). is Coupling of organometallics. The demetallative dimerization of RLi by CuCl2 give RSnBul Organostannanes by CuI.2 different from the conjugate addition catalyzed R-R when R is an alkynyl. alkenyl.or aryl group.' Hydrolysis of SAMP-hydrazones.a After asymmetric alkylation of the SAMPof the hydrazones,it is critical to generatethe chiral ketoneswithout racemization.Treatment a solution. provides ammonia productswith cuX2 in THF or MeCN followed by aqueous

Meo'-'"'a) N,NJ

--^y^-

aEnders,D., Hundertmark,T.,Lazny, R. SC 29. :5Takahashi,T., Sun, W.-H., Nakajima' K. CC l59J

l5: 19.I Copper(I)iodide.16,98;18' 11'1-1 oi l' reaction The Alkynyl ketones.t CuI-Et.N. Cyclization. Alkynesin which the tnp from a pronucleophlicsite undergoclchua Thetriplebondis actiral CuI andt-BuOK.2

lll x. cooMe tlt

v

|

|

? - : -

\,/

=

X = C N ,C O M e , . . .

Coupling between an imino chloride arx by cyclization.3This Pd-catalyzedprocer. r able decomposition occurs and the reactlon i

o THF ; NHg

#

tl

I (99% ee)

cyclooctatetraenes.5 (z,z)-1,3-Dienyl-1,4-dicopperspeciesare formed on treatment in the of zirconacyclopentadieneswith CuCl2. Further reaction with NBS results substitutedcyclooctatetraenes. IMa,S.,Wu,S.JOC 64,9314(1999). 2Pastor, I.M.,Yus, M. TL 4l' 1589(2000). 3Kang,S.-K.,Baik,T.-G.,Jiao'X.H.,Lee,Y-T.TL40,2383(1999)'

Either pyrroles or 3-pyrrolines are form formaldehyde and CuI.a

R

nf-\ Ar

i-Pr2NEt- HCrc . Cul

r

Copper(I) iodide

o. B-d

o'

!.'

,,R

147

aEnders,D., Hundertmark,T.,Lazny, R. SC 29, 27 (1999). 5Takahashi,T., Sun, W.-H., Nakajima, K. CC 1595 (1999).

\\

\lori. A., HiYama, T. JOC 65' 1780

19,109-110:'20,120-l2l Copper(I)iodide.L6,98;18,114-115; Alkynyl kptones.t The reactionof l-alkynes with acyl halides is promotedby CuI-EtN. by threeskeletalatoms Cyclization. Alkynesin which the triple bond is separated from a pronucleophlicsite undergocyclizationin the presenceof catalyticamountsof CuI andr-BuOK.2The triple bondis activatedon coordinationwith thecoppersalt.

rx)). l.

,

, \\. 'r. S \{ ACIEE39,237(2000);Han,G., r: \1 ./()C61,9483(1996). [t'

:0. I 20 '. hutenolideson reactionwith CuX2

I

d -

, L

-.

I.

: . c dimerizationof RLi bY CuCl2 is RSnBuj give t'ul.r Organostannanes :rrnctric alkylation of the SAMP.! rrhoutracemization.Treatmentof the .-','u:ammoniaprovidesa solution.

lll t \-,

xy.coottt" Cul - IBUOK l +

COOMe

THF

X = C N ,C O M e , . . .

is accompanied Coupling betweenan imino chloride and 2,2-dimethyl-4-alkynamide by cyclization.r This Pd-catalyzed process is aided by CuI, for without which considerable decomposition occurs and the reaction also becomessluggish.

.A ff-}

Cul - Pd

46%

F

(99% ee)

r::'

Either pyrroles or 3-pyrrolines are formed when N-propargylanilines are heated with formaldehyde and CuI.a

n1o-rspeciesare formed on treatment :cuction with NBS results in the

R

I

rT\

i-PrZNEt-HcHo aq +

cula

h\ ^'

nr-'JJ

>:\

n-N?

Ar It

_,.r 1999)

in dioxane in ethanediol

Copper(I)oxide

Desilylallylatian. 2-(1-Trimethylsilylalkenyl)thiopyridinesundergo allylation. Regioselectivity differences are noted for silylallyl- and silylvinyl-type substrates.s

(r

Cu;O- 3i

rtNqz

\____Z

DMSC .r:

Z"'att , + C u l- K F THF / lVle2CO

Me?Si

f"f\

rMoreno-Manas, M., Plexixata, R.,Villarrora. S

Copper(Il) tetrafluoroborate. pNitrostyrenes.t Styrenes undergr)r

)-,,"

.-2.-J.-)

Cul - KF

Cu(BFa)2and 12in MeCN.

THF / lVe2CO

78%

rChowdhury, C., Kundu,N.G.?55, 7011(1999).

2 Bouyssi,D., Monteiro, N., Balme, G. TL 40, 1297 (1999). 3Jacobi,P.A.,Liu, H. "/ACS121, 1958 (1999). alayaprakash,K., Venkatachalam, C.S., Balasubramanian, K.K. TL 40,6493 (1999). sTakeda,T., Uruga, T., Gohroku, K., Fujiwara, T. CL82l (1999).

Copper(Il) nitrate. 15, l0l; 18, 115-116; 19, I l0:20, l2l Biaryls.' Diarylstannanesincluding heteroaromaticanalogues(furan and thiophene series) undergo reductive elimination on treatment with copper(Il) nitrate trihydrate in THF at room temperature. Azidolysis of glycidic acids.2 In the presence of copper(Il) nitrate trihydrate, regioselectivering opening of the epoxide by sodium azide in water (pH 4) to provide 3azido-2-hydroxy carboxylic acids is observed. N-Nitro-1-methyluracil,\ l-Methyluracil undergoesN-nitration with a mixture of copper(Il) nitrate trihydrate and acetic anhydride, while nitration occurs at C-5 in fuming nitric acid.

rCampos, PJ.,Garcia,B., Rodriguez, M.A r1.I

Copper(I) 2-thiophenecarboxylate.19. t I Enami.des.t Enamides are prepartrJ NMP with Cs2CO.,asbase. lShen,R.,Porco, J.A.OL2, 1333(2M).

Copper(Il) triflate. 19, I 12;20, 122-l)] Cleavage of aziridines.t Coppenllr aziridinesby arylamines. Mukaiyama aldol reaction: With C cnol etherswith aldehydescan be carriedtr Acetylation. Alcohols, thiols. and ar reactionwith aceticanhydrideat room rem

are similarly transformedinto gem-diaceta N-Arylimidazoles.s Together *irh L as additives,Cu(OTf)2and cesiumcarbona

rHarada, G.,Yoshida, M., Iyoda,M. CL 160(2000). 2Fringuelli, F.,Pizzo,F.,Vaccaro, L. SZ311 (2000). 3Giziewicz, J.,Wnuk,S.F.,Robins,M.I. JOC 64,2149(1999).

lSekar, G.,Singh, (t999r. V.K.JOC 64,2537 rKobayashi, S.,Nagayama, S.,Busujima. T. (-/-I rsaravanan, P, Singh,V.K.TL40,26ll (lD99, rChandra, K.L.,Saravanan, P.,Singh,V.K.51,ri( sKiyomori,A., Marcoux,J.-F.,Buchwald. S.t- fl

Copper(I) oxide. 16, 99 Perfluoroallcylation,t By using Cu2O as the catalyst, anilines undergo perfluoroalkylation with RrI in DMSO at 130'. The perfluoroalkyl groups enter at ortho- and para-positions that are open. N,N-Dimethylaniline suffers demethylation in the

Copper(II) trifluoromethylthiolate. 19. I I Trifluoromethylthioarenes,t Arl laml in the presenceof the title reagent.

process.

'Adams,D.J.,Goddard, A., Clark,J.H.,Macqur

Copper(tr) trifluoromethylthiolate

allylationRegiorx. ..:rJcrgo t',:--.uhstrates.s

Cu2O - CsF17,

( \

/FNH2

/

---------------------_ ceFrzl Dr,,4soi3o'

_--'"u'u ,/-\ //-* , CeFrz

: r l \

^ . / Vl

l

I 5-/o

rMoreno-Manas, M., Plexixata, R.,Villarroya,S.Sa 1996(1999).

:: \\ I '. ''-Z

Copper(Il) tetrafl uoroborate. B-Nitrostyrenes,t Styrenesundergo nitration with sodium nitrite in the presenceof Cu(BF.), and I, in MeCN. rCampos,P.J.,Garcia,8., Rodriguez,M.A. TL 4l, 9'79 (2000).

e

Copper(I) 2-thiophenecarboxylate.19, I l2; 20, 122 Enamides.t Enamides are preparedby coupling alkenyl iodides with amides in N M P w i t h C s ; C O 1 a sb a s e . J r ' : , ) r( 1 9 9 9 ) .

lShen,R..Porco,J.A.OL2, 1333Q000).

Copper(Il) triflate. 19, l 12; 20, 122-123 r.: :Lrc:(furanand thioPhene tn r : - : ' . : l l t n i t r a t ct r i h Y d r a t e . ::.crrll) nitrate trihydrate, ....itcr(pH 4) to Provide3:

Cleavage of aziri.dines.t Copper(Il) triflate is a good catalyst for cleavage of aziridinesby arylamines. Mukaiyama aldol reaction r With CutOTf), as catalyst, the condensation of silyl enol etherswith aldehydescan be carriedout in aqueousethanol. Acetylation. Alcohols, thiols, and amines are acetylated by a Cu(OTf)2-catalyzed reactionwith acetic anhydrideat room temperature.rVariousaldehydes(but not ketones) aresimilarlytransformedinto 3erz-diacetates.a

.\ r-:

'r.rtlonwith a mixture of . rlccursat C-5 in fuming

N-Arylimidazoles.5 Together with 1,10-phenanthrolineand dibenzylideneacetone as additives,Cu(OTf), and cesiumcarbonatepromoteformation of N-arylimidazoles. rSekar, (1999). G., Singh,V.K.JOC 64,253'7 rKobayashi, S.,Nagayama, S.,Busujima, T. CL'11(1999). tsaravanan, P.,Singh,V.K.TL40,26ll(1999). +Chandra, K.L.,Saravanan, P.,Singh,VK. Sa 359(2000). 5Kiyomori, A., Marcoux,J.-F.,Buchwald, S.L.fL 40, 2657(1999).

.rnilines undergo Perr,.. li'.. :roups enter at ortho- and l::- . demethylationin the

Copper(Il) trifluoromethylthiolate. 19, I 12: 20, 122-123 Trifluoromethylthioarenes.t Arylamines are converted to ATSCFTby diazotization in the presenceof the title reagent. rAdams,D.J.,Goddard, A., Clark,J.H.,Macquarrie, D.J.CC 987(2000).

150

Cyanomethylenetriorganophosphoranes

1-Cyanobenzotriazole.

p-Cyclodextrin.

Aryl cyani.des.r Cyanation of ArLi by the title compound is expedient. rHughes, T.V.,Cava,M.P.JOC 64,313(1999). N-(2-Cyanoethoxycarbonyloxy)s-uccinimide. Amine protection.t Amino groups present in oligonucleotides are readily protected with this activatedcarbonate1 in the form of carbamates.

4 I

2-Amino alcohols. Epoxides are op trimethylsilyl azide2in the presenceof p-c1r Tbrephthalic acid. Benzene is selecrr yield) in a Cu mediatedreaction with CCl. r The C-{ bond formation occurs when benz

rReddy, L.R.,Reddy,M.A., Bhanumathi. N.. R.m 2Kamal, A., Arifuddin,M., Rao,M.V.IA 10.{:61 rShiraishi, Y.,Tashiro, S.,Toshima, N. Ct 8lE , -'{

,o

Carbonylhydridotris(triphenylphmphim I Hydroformylation I Wttig reactionaccomplished.

N-O

\ o otr",\

CN

(1)

>..,

H2tco.

rManoharan, M., Prakash, T.P.,Barber-Peoc'h, I., Bhat,8., Vasquez, G., Ross,B.S.,Cook,P.D.JOC 64.64681999\.

,nre^y'

1-Cyanoimidazole. Cyanation.t This reagent is prepared from imidazole and cyanogen bromide. It donates the cyano group to various nucelophilessuch as amines, thiols, and RMgX (or RLi). rWu,Y.,Limburg,D.C.,Wilkinson,D.8.,Hamilton,G.S.OL2,795 (2000). Cyanomethylenetriorganophosphoranes. Cyanomethylenation of carbonyl compounds. This powerful Wittig reagent MeIP--CHCN reacts with esters,lactones,and imides.r The reaction is valuable for synthesis of C-glycosides fiom glyconolactones and Phrh-{HCN. Microwave shorlensreactiontime to minutes.z assistance

rBreit,B.,Zahn,S.K.ACIEE38,969 (1999t ( 1,5-Cyclooctadiene)(1,3,5-cyclooctatrier

Isomerizatinn.r 2-Allylphenol is isom (cod)Ru(cot)in methanol at room tempera Triethylphosphineis also added. rSato,T., Komine,N., Hirano,M., Komiya.S. ('/. ( 1,5-Cyclooctadiene)cyclopentadien.r-lcnb

I * .'cN pnAoet [t",

"cN

This nrttr [2 +2 +2]Cycloaddition.t alkynesand a nitrile, has beenextendedro th

PhN.4e 100'

*{o=,

R

.lll lTsunoda,T., Takagi,H., Takaba,D., Kaku, H., Ito, S. TL41,235 (2000). rlakhrissi, Y, Taillefumier, C., Lakhrissi, M., Chapleur,Y. TA ll,4l7 (2000).

I

R

clrcr r,u.

l5l

(1,5-Cyclooctadiene)cyclopentadienylcobalt

p-Cyclodextrin. nr:. ..:-,Jts exPedient

" protected F, ..-lc'rrtidesare readily

2-Amino alcohols. Epoxides are opened regioselectively with arylaminesr and trimethylsilyl azidezin the presenceof B-cyclodextrin. Tbrephthalic acid. Benzene is selectively converted to tetrephthalic acid (46 mol%o yield) in a Cu mediatedreaction with CCla in the presenceof NaOH and B-cyclodextrin.r The C-{ bond formation occurswhen benzeneis trappedin the cavity of B-cyclodextrin. rReddy, N., Rao,K.R.S4 339(2000). L.R.,Reddy,M.A., Bhanumathi, 2Kamal,A., Arifuddin,M., Rao,M.V. fA rc, 4261(1999). sshiraishi, N. CZ 828(2000). S.,Toshima, Y, Tashiro, Carbonylhydridotris(triphenylphosphine)rhodium. Hydroformylation + Wittig reactian,t The

tandem process on

alkenes is

accomplished.

/'\'\-/"\ :

H2lCO- (PhrP)3Rh(CO)H

( i . . R o s s ,8 . S . , C o o k , P . D .J O C

enre^\o

phMe eo"

etoocv,,y,,Z{ :

!l .1.:

U.

.:

-

Ic

.:'

and cyanogenbromide. It rmines, thiols, and RMgX

- < l0fx)).

r. I :rr. powerful Wittig reagent fhe reactionis valuablefor u--r ,',1 PhIP-CHCN. Microwave

:

f

.cN

i

,nAoEt

I f!

.: l r x ) 0 ) . lr :1112000)

l

O

60% (syn : anti 9:1)

lBreit.8.. Zahn.S.K.ACIEE38,969(1999\. ( 1,5-CyclooctadieneX 1,3,5-cyclooctatriene)ruthenium(0). Isomerization.r 2-Allylphenol is isomerizedto 2-propenylphenolin 957oyield with 'the (Z/E) ratio of the products is 94:6. (cod)Ru(cot) in methanol at room temperature. Triethylphosphineis also added. rSato,T., Komine,N., Hirano,M., Komiya,S. CL44l (1999). ( 1,5-Cyclooctadiene)cyclopentadienylcobalt. [2 + 2 + 2]Cycloaddition.t This method of pyridine formation, which unites two alkynesand a nitrile, has beenextendedto the synthesisof spiroannulatedanalogues.

R'

. l Il l +#1*R' I

R

r52

Cyclopentadienylbis(ethylene)cobalt

rVarela, L., Saa,C. OLl,214I (1999). J.A.,Castedo, (1,5-Cyclooctadiene)(nu-naphthalene)rhodium(I) tetrafl uoroborate. This cationic rhodium complex is useful for inducing the [4 + 2]Cycloaddition. cycloaddition ofconjugated dienesto unactivatedalkynes in dichloromethane(15", 15 min), I forming I .4-cyclohexadienes.

4 6,I \.,^ru' o2"'V

rPaik,S.-J.,Son,S.U.,Chung,Y.K.OL1,2045(1999). (1,5-CyclooctadieneXr1o-tetraphenylborato)rhodium(I). Hydroformylation. Alkynes undergo hydroformylation to afford branched-chain aldehydeslor lactones.2

co-H2 (Pho)3P / cH2ct2

t 2Y

aY

tPerez,D., Siesel, B.A.,Malas r Eichberg, M.J.,Dorta,R.L..f2

Cyclopentadienylindium( I t Cy cIop en tad ie ny lc arbin ln water.

cHo 55%

/\ \ . / (

\t/

,)-e'

*Rh(cod)

\^ t'

7.

I

lYang.Y.. Chan.T.H. JACS 122.

91o/o rvandenHoven,B.G.,Alper,H.JOC 64,3964,9640 (1999). 2vandenHoven,B.G.,El Ali, B., Alper,H. JOC 65,4131(1999). Cyclopentadienylbis(ethylene)cobalt. [2 + 2 + 2]Cycloaddition. Extension ofthis cycloaddition method to annulation of benzofuran successfullyelaboratesfour rings of the morphinoids.' A strychnine synthesis2has beencompletedbasedon an analogouselaboration.

f
r;:

phcooEt

-

l

A propargylic carbonate or phosp via the allenyltitanatespecies.e

Certain 2-alkylidenecycloalkano lar processinitiatedby cyclotitanarro

88% (trans j cls 93 : 7)

4\\(n

Reaction with alkenes and aWnes. In the carbosilylation of alkenes and dienes with carbon fragment that comes from a secondary or tertiary alkyl halide, promotion by BuMgBr/Cp2TiCl2 is efficient. Primary alkyl halides are less suitable contributors unless the reaction is intramolecular. The regioselectvity of this process is such that the silyl group is branched out.5

ph,,/ -

ll

ti l ll r o

't

I

K

-cp2ricr2>tn7f4BuMscr tBuBr. Et3SiCl

I

c+^ii

94%

tn6A.Ar,.

I

BuMgCl- Cp2TiCl2 MetSiCl

,,.YO Me3Si

Reductive cleavages. Dia4l dl BuMgBr/Cp2TiCl2 system. Alkl.-lar respectively.

Both the removal of the ester gru (alsoArBr, ArI)ra are accomplishedar Allyl ethersand allylaminesun&r rcgioselectivelyaccordingto the rrtan

87% /-)

o.

Hydrotitanation of l-silyl- and l-stannyl-l-alkynes leads to B-silyl (or Bstannyl)alkenyltitanates,6 thus showingoppositeregioselectivityto other relatedprocesses (hydroboration,hydroalumination,hydromagnesiation,hydrotitanation,hydrozincation, hydrozirconation).Well-defined alkenes are obtained on further reaction of the alkenyltitanates,for example,with allylic carbonatesan Sx2' displacementoccursto afford 1,4-dienes.7If another alkyne is added before protonation of the titanacyclopropenes(to give the alkenyltitanates),then the intermediates are transformed into titanacyclopentadienes, and henceto conjugateddienes.n

\_-2

XY o-

rll R

R^Tix3 Me3Si..".-[Ml

*.iJ

I

Er--C

+ Cp:T + EBT

t"rt') SiMe3

t-\

f).* \-J

ll -------.---.-(i.Pro.-

M= B,Ms,At,zn,zr

Cyclization. If a proper learrng ,liene,an opportunity for eliminarionc resultingalkyltitanium speciesmar hc hasbeendevelopedaccordingly.

Grignard reagents-titanium{IVlcompounds

Measirt-Ph - ,oH

i:-

A propargylic carbonate or phosphonatemay be converted to a hydrazino derivative via the allenyltitanatespecies.e Certain 2-alkylidenecycloalkanols are synthesizedfrom alkynones by an intramolecular processinitiated by cyclotitanationof the triple bond.r0

88%(trans:cis 93 : 7)

.di.n

r- .rlrlation of alkenesand dienes o: ::1ritn' alkyl halide, promotion by r tr:- ..\s suitablecontributorsunless r,' ''i- processis such that the silyl

-,

Y

c

'h,

Y/\ l Et.si

-,/ l I

94%

:- ^ltn

flf 'l'

3

.L{* -(tsPro)ari i-PrN'4scr ; Ytot ll R'^x

R'

X = H ,l n=1,2

Reductive cleavages. Diaryl disulfidesrrand ditelluridesr2are cleaved with the rBuMgBr/Cp2TiC12system. Alkylation results in alkyl aryl sulfides and tellurides, respectively. Both the removal of the ester group from a B-ketoesterrrand dechlorinationof ArCl (alsoArBr, ArI)ra are accomplishedat room temperature. Allyl ethersand allylaminesundergodimerization,rswhereas 1,6-dienesare cyclized regioselectivelyaccordingto the titanium complexesused.ro

Me3Si 87Yo

1-},o,,

.:rc\ leads to B-silYl (or Pprocesses t ' ' r.tl\ ity to other related 'i hydrozincation. r tlrotitanation. 1: '' iunher reactionof the alkenyltit\: .:-l.rccmentoccursto afford 1,4-di(to give : thc titanacycloProPenes

r-

: :Ic'd into titanacyclopentadienes,

\-J ,/-\ o ll \_-,

(i.pro)ari

H HOJ

\_OH

( d l: m e s o > 9 6 : 4 ) 51%

)") *,,,,Fo,

\

?

f1o

a'

B fJ,,,,-OME -N.

t2

OMe

Bn

/

6 \

UIJ

,,R, \_1

to-\-42t"

| \o/^ ),,,r'-,,-lt"

n=1,2

Bicyclization involving an intramolecularacylation is further extendedto include an aldolization.reA route to bicyclic enoneis basedon controlledprotonolysisof the titanacycle and subsequentcyclization.This synthesisis amenableto asymmetricinduction.20

Homoenolate and homoalleayl cnolate speciesare basedon the actrq titanatesgeneratedfrom acetalsof rm

iicetals are similarly cleaved to a.f carbonates are transformed into r l compoundswith ^y-selectivity.rr

rO. t F o

ior-^ | /-w

a)

.Y ................"'..".'................'"."'..................................* "\

\-\'o '

i-PrN,lgBr-(i-PrO)aTi ; s-BUOH

l-42:-siMe.

I SiMe3

T t

-\_/ /

-q .a n 17

\-/

54Yo The possibility of forming a bridged tricyclic system by an intramolecular reaction of an imide2ris of syntheticsignificance.

.v

I

I

H 1 9

\.,N : H

N

Z

U

R

G"n"'

.........................................._ (i-PrO)3TiCl ;

X

O2

The Cp2TiPh species generatedfrom addition of PhMgBr to the l-PrMgBr-Cp2TiCl2 system is able to induce cyclization of D-ketonitriles to cyclopentanolones.22The vinylogues afford 2-hydroxycyclopentaneacetonitriles.

t"-.

Following activation of conjugared c rmines gives products with multiple srer

Me?Si _P2 '-icl2

\\

..--_ [cornpt i_prMscl

\ '\2. R'

a,a-Dimethylamines.26 Reductnt reaction with MeMgBr in the presenceol

Grignard reagents-titanium(IV)compounds

J

--cooH

l "'te

/--(o

\-f,

\..r\cooH N

H

c

OH rP

r-4, t

Cp2TiCl2

(

i-PrMgCl; PhMgBr

\-f-J

H

H

77%

(-)-kainicacid

r h o te l

)

CN Cp2f i0l2

x

i-PrN,lgCl PhMgBr

^

K

R

/

' 64Yo

\o-\.,42t" H

i. lurther extendedto include an [. '::r()llcd protonolysisof the titanan 'r.rhlc to asymmetricinduction'2o a::'-

Homoenolate and homoallenyl carbanion equivalents. Two routes to homoenolate species are based on the action of (propene)titanium diisopropoxide. Trialkoxytitanatesgeneratedfrom acetalsofacrolein react with aldehydesand imines. Chiral cyclic acetals are similarly cleaved to afford the nucleophiles.zr3-Alkoxy-2-propyn-l-yl carbonates are transformed into (l-alkoxyallen)-1-yltitanatesthat add to carbonyl compoundswith T-selectivity.2l

n ./v,

.^)

l F o

).'

/-+/I \ ^

'>J

\

o

I SiMe3

Cp2TiCl2 i-Pr[rgcl I

*-*4*'

a) -

ron ,,-)""'\-o,,r1n' NHR" \_,/

54% ;r . - :: hr an intramolecularreactionof

Following activationof conjugatedenynes,the reactionwith carbonylcompoundsand iminesgivesproductswith multiplestereocenters.z5

:

:

N^Ph

Me"Si

^-ict2 vP2l

\

\ '\2. '

R

'

+ [complex] i-PrMscl :

tl

HN^Pn Me?Si -

l,/zv

r' tr

r : t'!\leBr to the i-PrMgBr{P2TiClt The vinyr: :- :,, cvclopentanolones.22

.4{a,' R'

a"a-Dimethylamines.26 Reductive methylation of tertiary amides occurs on reaction with MeMgBr in the presenceof TiClo @r ZrCl) in THF.

Grignard reagents-zirconiumcompounds 'Cho, S.Y.,Cha, J.K. OL2, 133'7(2000). 2Raiman,M.V, il'ina, N.A., Kulinkovich, O.G. Sa 1053 (1999). 3Winsel, H., Gazizova,Y., Kulinkovich, O.G., Pavlov, V., de Meijers, A. SL 1999 (1999). lMizojiri, R., Urabe,H., Sato,F.TL40,2557 (1999). 5Nii, S., Terao,J., Kambe, N. ,/oC 65, 5291 (2000). 6Urabe,H., Hamada, T., Sato, F. JACS 121,2931 (1999). TOkamoto, S., Takayama,Y., Gao, Y, Sato, F. S 975 (2000). 8Hamada,T., Suzuki, D., Urabe, H., Sato, F. JACS l2l,'1342 (1999). ' An, D.K., Hirakawa,K., Okamoto,S., Sato,F. TL 40,3'137(1999). r0Morlender-Vais, N., Solodovnikova,N., Marek, I. CC 1849 (2000). I lHuang, X., Zheng, W.-X . SC 29, 1297 (1999). r2Huang,X., Zheng,W.-X. SC 30, 1365 (2000). r3Yu,Y., Zhang,Y. SC 29,243 (1999). raHara,R., Sato, K., Sun, W.-H., Takahashi,T. CC 845 (1999). rsdeMeijere, A., Stecker,B., Kourdioukov,A., Williams, C.M. S 929 (2000). 'oOkamoto, S., Livinghouse, T. OM 19,1449 (2000). rTCampbell,A.D., Raynham,T.M., Taylor,RJ.K. CC 245 (1999). rsTakayama, Y, Okamoto,S., Sato,P. JACS l2l,3559 (1999). reOkamoto,S., Subburaj, K., Sato, F. JACS 122, 11244 (2000). 20Urabe,H., Hideura,D., Sato,F. OL2,38l (2000). 2 r S u n gM , . J . ,L e e ,C . - W , C h a ,J . K . S L 5 6 l ( 1 9 9 9 ) . 22Yamamoto, Y., Matsumi, D., Hattori, R., Itoh, K. JOC 64,3224 (1999). 2iTeng,X., Takayama,Y, Okamoto,S., Sato,F. JACS l2l,11916 (1999). 24Hanazawa,T., Okamoto, S., Sato, F. OL2,2369 (2000). zsHamada,T., Mizojiri, R., Urabe, H., Sato,F. JACS 122,7138 (2000). 26Denton,S.M., Wood, A. Sa 55 (1999).

Grignard

reagents-zinc

Reductive

alkylation.

*/

lvlgB

l,S-Dienes and l,S-envnttnentenes(derived from alkr.rrs. rre treated with alkynylmetals. h s ith iodine gives 1,5-enynes.

Cp2ZrCt2 K:K

R

EtMsBr

Cp-Z)

Alkenylcyclopropanes.a

Th

borohydride. Esters

are converted

to

secondary

alcohols

where

the

F.tMgBr and Cp2ZrCl2 converr-s r}r

G r i g n a r d r e a g e n tc o n t r i b u t e s o n e a l k y l g r o u p . l

R'MgBr

R.

R_COOEI +

Zn(BHiz

FOH R,'

rHallouis,S., Saluzzo,C., Amouroux, R. SC 30, 313 (2000).

Grignard reagents-zirconium compounds. 18, 174; 19, 1611,20, 180-1 8 I Organozincation.t On reaction with EtMgBr-Cp2Z{12, 1-alkenesgive 2-substituted dialkylzincs that can be usedin coupling reactions. Alkylsilanes.2 Grignard reagents are isomerized by Cp2ZrCl2.Subsequentreaction with hydrosilanes in the presenceof an alkyl bromide leads to silanes bearing a primary alkyl group.

Gagneur,S., Montchamp,J.-L.. \egu t'ra, Y., Hara, R., Takahashi.T. CC tl Dumond,Y.,Negishi,E. JACS l2l. l' 'Bertus, P, Gandon,V, Szymonral-J

ztl

Grignard reagents-zirconium compounds

R \

: , \ l e r l e r sA. SL 1999(1999).

i [r, -:r_ 1999). . :-:- rq99).

. ._.:rxn).

Cp2ZrCl2

t

Y MgBr

R. z'\ v siHPh2

B(CH2)3Br Ph2siH2

7,S-Dicnes and 1,S-enynes,3 Insertion reaction takes place when zirconacyclopentenes(derived from alkynes, ethylmagnesium bromide, and zirconocene dichloride) are treated with alkynylmetals. Protodemetallation leads to l,5-dienes, whereas oxidation with iodine gives 1,5-enynes.

R \: \ 919(2000).

!.

cp2ztct2

*t-J*

R'---€-rvi

CpZr

':t

D--E-D

R

/\

EtMsBr Cp2ZrJ

/

)

-

I i - , ,

*


x-,}_ -T,

}> o l -).\..R'

Ph,Pi rHF

\

u I o P h

r-- [l

J

'i ,rl leads to dihydropyran derivattves' An alkyne/5-hydroxy-2-pentynoic ester coupling ethyl 6-hydroxy-2-hexynoate proceedsin Formation of the homologoo' h"t"'otytle from Pd(OCOCFTI:''a two stages,the secondstageis promotedby

*

R--

/-P)^

HO

Pd(OAc)2 / PhH

OMe

J

o \ 'T

):\

r,/1

l-

'nnncr vvvLl

f( )+-P LYI: ON4e

Annulation,

tosylate tsenzyne rs probably generated from o-trimethylsilylphenyl

t1 "U::l-.1^n:*"nthrene is by CsF.Aunion of two benzvnemolecules1d.the f] | \

rl-]' AcO

96Yo

I

|:1 =', i t L t

Phenyliodine(Ill)

bis(trifluomacetate)

Dehydration.2 Alkanamides are dehydrated to nitriles by this reagent, but formamides give isonitriles. 'Millan,D.S.,Prager, R.H.AJC 52,841(1999). 2Bose, D.S.,Goud,PR. TL 40,747(1999'). Phenyl(fluoro)iodine triflate. 20, 304-305 Oxidative rearrangement,t (PhIF)OTf induces reiurangement of nonterminal alkynes in an alcohol to give a-branchedesters.

rll + Pn-r-r -il.* pnlcoov" I Ph

rTohma, H., Watanabe, H., Takisag.a-S. rKita, Y., Egi, M., Ohtsubo,M.. Sarh. T 'Kita, Y., Egi, M., Tohma,H. CC l.l_r, l, rVarma, R.S., Kumar, D. "/CS(p/ r I ?J5 i squideau,S., Looney, M.A., pouvscgu-I

Phenyliodine(III)

diacetate.

13. l{

280-281 ; 18, 290-29 | ; 19, 268-: -C Diaryliodonium sulfu natcsadmixture with PhI(OAc)2.2TfOH u

Oxidations, 4-Hydoxy-2-crcl with PhI(OAc)r. 2-Methoxyphenols adducts.3'a

Tfo-

rPirguliyev,N. Sh., Brel, V. K., Zefirov, N. S., Stang,P.J. MC 189 (1999).

Phenyliodine(Ill) bis(trifluoroacetate).13,241,242;14,257; 15,257-258; 16, 274-275: 18, 289-290:19,267-268: 20, 305 Cyclizations,Annulationaccompanies oxidationof N-sulfonyl-4-methoxyanilines with PhI(OCOCFj)2 in the presence of 1-alkenes.r5-Methoxyindoles or indolinesare producedin this one-potreaction.Cyclizationof 3-arylpropylazideswherethe aromatic ring is activated(e.g.,3-methoxylated) to fusedquinoneiminesis observed.2

Meo--4 I ll

* A "rln

Pht(ococF3)2

o€[3'n

9xHr.

MeOOC...,,,1.-.OMe

-l ll\v\oH

+ rt,t€

Acylnitroso compounds gerrre alkenesin situ. O-Acetylationand rc 2-(B-Indolylethyl)oxazolines arc

Ts 65%

2-(m-Methoxyaryl)ethyl benzyl sulfides are similarly cyclized to S-benzyl-2,3dihydrobenzothiophenes.3 Dehydrogenation.a 1, 4-Dihydropyridines are rapidly aromatized on exposure to PhI(OCOCFI)2 although addition of sulfur and microwave irradiation of the mixtures has the sameeffect. Dearomatization.s 2-Substituted l-naphthols are allylated at C-2 when they are exposedto PhI(OCOCF3),and an allylsilane. 1-Trimethylsiloxy-1,3-butadiene also react with the naphthoxyiodonium species.

Pht(ococF3)2

05*."".''o\

cH2ct2

With a (salen)CrCl complex as with PhI(OAc)2is chemoselecrir.e Ring contraction. A facile srr is by oxidationof 2-alkylideneclclo

o tl

(Y^

Phenyliodine(tfl) diacetate

rnles by this reagent, but for-

}, :;.:::rh9€lTl€ntof nonterminalalkynes

=-.lcooMe

l: I

rTohma, H., Watanabe,H., Takisawa, S., Maegawa, T., Kita, y. H Sl, l7g5 (lg9g). 2Kita, Y., Egi, M., ohtsubo, M., Saiki, T., okajima, A., rutuou, r., Tohma, H. cpB 47,24r (rggg). rKita, Y, Egi, M., Tohma, H. CC 143 .:Igg9\. rVarma. R.S.. Kumar. D. JCS(pt ) l7S5 (lgggt. sQuideau, S., Looney,M.A., pouysegu. L. OL l,I651 (1999).

Phenyliodine(Ill)diacetate.13,242_243;14,25g_259;15,25g;16,275_276;17, 280-281;18,290-291;19,268_270;20, 305_307 Diaryliodonium surfonates. These salts are prepared from ArB(oH), upon admixrurewith phI(OAc)2.zTfOHin dichloromethane. I oxidations' 4-Hydoxy-2-cyclobutenones are oxidized to -y-acetoxybutenorides2 with PhI(oAc)r. 2-Methoxyphenols give o-quinonesthat can be ffappedu, Di"lr-Ald". adducts.3'a

.q, 1999).

l/

t . '

I J. 157; 15, 257-258; 16,

Meooc)i'lYo'" * ""o$ ffi \V\oH

''i

.\'-sulfonyl-4-methoxyanilines ' \lc-thoxyindolesor indolines are

OMe

#ffi"""

rsoH_H2c

\_/

a(

' , .:rlnesis observed.2

.

\{eo:y';-1

-

|

ll

\An'\

) . t

aziridineesters.la

t-BuoK/rHF Ph"\,\-cHo

-'0"

|

I

j.,

t ' 4

o

71Yo

,oMe \-o

a ' r

iti = f'-

Amides. Conversionof ".te.. r.l heating with solid t-BuOK.i: Orrd.rr aldehydeswith t-BuOK in DMSO alro Hydrolysis. Amino esters ro- a (r-BuOK-THF) at 0' or belor,r'.Thrr

2-Alkylideneglutaronitriles are readily formed by consecutive Michael and Wittig reactions.6 The process involves addition of the cyanomethylphosphonate anion to acrylonitrile and quenching the homologated anion with aldehydes.

IBUOK / THF . HN,IPA ;

ot l

ffiP;.cru

.

\

\

J

on"'-*t

Y / \

t-BuOK

--f

2a

Ph,,\.CN

PhCHO;HCl-H2O

I )

CN

CN

Claisen rearrangement Allrl d propargyl ethers with l-BuOK are rc.( o-substitutedacroleinsis established

72o/o Cyclizntians. Synthesis of substituted indoles from o-haloanilines by condensation with ketones?or nitriless is promoted by t-BuOK in DMSO. Furansare formed from a-propargyl ketones.qAlkynyl benzyl sulfidescyclize to give 2-aryl-2,3-dihydrothiophenes.r0 Deprotonation at the benzylic position initiates the cyclization.

l--\

( \:

./

,r-s

\

N

\}-r \\ / \ \

t ? \

(YY '

I-BUOK/ THF

,)'\?-.'

I-BUOK/MeCN

Al.dol reactions. A reagentconur Addition to styrenes. A caralrrr additionof ketonesand iminesto sgl6

o. 7SYo

at room temperaturein either DITISOtr

Potassium,-butoxide

-\n alkyne synthesis bY chain rh, -rhonium salts as Wittig reagent r:l:lrning whether the products are

Aromatic substitutions. 2-Nitroaryl-1,3-dithianes are assembled by the vicarious II nucleoohilicsubstitution on nitroarenes.

/ _r:il^N. -50'

R=l

+25o R=H

95Yo

97Yo |'lYo

f-i:fi()lates and their O-acylatedand

Amides. Conversionof estersto amides in a solvent-freeprocessuses mrcrowave heating with solid t-BuOK.12Oxidative decyanationof ct-aminonitrilesderived from aldehydeswith r-BuOK in DMSO also afford amides.rl Hydrolysis. Amino esters (ct- and B-) are cleaved under nonaqueous conditions (I-BuOK-THB at 0o or below. This method proves valuable for kinetic resolution of aziridineesters.ra

Ph\cHo ;_

o ,oMe \_o

75% t^. ,,)n\ecutive Michael and Wittig anion to i -r.1nr)methylphosphonate

o

L-{ K

Phs

\

I B U O K/ T H F

20"

r ::: .!lJehydes.

c - ,

(""fv. /\

,^...!_*X 42%

PhryCN I \ I CN

o

(o""-.\.o^ ,n.!tX 58To

Clnisen rearrangemenf. Allyl allenyl ethers resulting from isomerizationof allyl A route to propargyl etherswith l-BuOK are ready to undergoClaisen rearrangement.l5 o-substitutedacroleinsis established.

72Yo ; :: nr o-haloanilinesby condensation

[ ) \ 1\ o \:i.::rr I benzyl sulfidescyclize to give r:.. hcnzylic position initiates the

| ?-\

(YY a'.O"-

IBUOK / THF

\

| ?^cs I o*,, /'-+4" o

Ts R--N-..,

rlrr

Ruthenium-carbene

complexes

are pleasing becauseof their Structural modifications such as those shown below22'23 high efficiency.

i")

o

(1)

o

ethylene cH2cl2

OTBS

a . ' . t..:. 'r_.:. t

,

** a$,", t

tl

l.l-dioxolane derivative, the ,-brevicomin.re A routeto (+)I er clization-fragmentationap,,n of 2-hydroxycycloalkanones ':r,1o'-positions.2l

t

u

bn

OTBS

Higher activity of catalysts embodying imidazolin-2-ylidene ligands (e.g., 3u) for RCM has been observed.2aSuch complexes as 3u and 5 allow formation of tetrasubstiThe and various functionalized analogues(e.g., 1-cyanoalkenes2T). tuted cycloalkenes,25'26 highly active catalyst 9 is recoverableand recyclable.28

ETOOC\f-/ x + Etooc'

exo-brevicomin

(3u) ETOOCV^I / \ r l \"/ Etooc-

,

100Yo Cross-metathesis. Functionalization of terminal alkenes by the metathetic method using catalyst L has been well established.The reaction between styrene and vinylsilanes gives co-silylstyrenes,2ebetween allylarenes and acrylonitrile leads to 4-aryl-2butenonitriles.3oAlternatively, homo-metathesis of two allylarene molecules to give 1,4-diaryl-2-buteneis first carried out and the cross-metathesisfollows.rr Also of interest

- -l-.,-1 6 - | endo-brevicomin

is the homo-metathesisof monosubstitutedallenes to symmetrical allenes.r2

s

tt'

RAc-

-

RAn

"cgHrg I

CgHrs

[

(+)-malyngolide

Both catalysts I and 2 are effective in promoting cross-metathesisleading to vanous conjugateddienes from alkenesand alkynes.13s4Chiral2-(ct-acetoxybenzyl)-1,3-butadiene is obtained from (R)-3-acetoxy-3-phenylpropynevia cross-metathesiswith ethylene.rs Furthermore,the reaction of 1,6-diyneswith alkenesis even more intriguing:r6

COOMe

.

-: .*

/ -)--.- \ / \

\

\-+/f Il o

ll

-n

Ts R -,.

I

N.r

-\

l*

ilt ill

(1)

'R'------*

I a

Ia

Ruthenium--carbenecomplexes

The scope is further expandedby using catalysts 3s37.38 and 4.3eFor example, it allows the preparation of trisubstituted alkenes by an intermolecular reaction for the first time,a0 and 1,5-cyclooctadienes(e.g., a precursor of aristeriscanolidear).The intramolecular version is a useful preparation of some other interesting molecules.a2

74Yo

aristeriscanolide

Technically significant is the finding that 4 can be generated in situ from I and 1,3-dimesityl-4,5-dihydroimidazolium tetrafluoroborate (treatment of the salt with I-BUOK in THF at room temperaturefor < I min). The RCM is performed in the presence of etherealHCl.a3 Complex 10 is a very active catalyst for ring-opening cross-metathesisof norbornene derivatives.aa [2 + 2 + 2]Cycloaddition. Formation of benzene derivatives from three alkyne units is catalyzed by several transition metal reagents. 1,2,4-Trisubstitutedbenzenesare the major products from reactions using the Grubbs catalyst containing Ph.P ligands.as Differences in regioselectivty for reactions promoted by the Grubbs and Wilkinson catalystshave been noted.ab

*or. (1)

RO-\ cH2ct2

Ro. ,:Co"

lf*.Y maJor

*T.li -,,*35*.r.*d* (1) 5-6 (Ph3P)3RhCl 1 Radical addition.aj (PhjP)2Ru(:CHPh)C12.

'l 1. 5 - 1 0

Carbon tetrachloride adds to alkenes in the presence of

Scholl,M., Ding, S., Lee, C.W.. Grubtr :Fiirstner, A., Liebl, M., t-ehmann. C Dixneuf, P.H. CEJ 1847 (20001. 'Jafarpour, L., Nolan, S.P OZ 2. JO-: ': 'Yao, 39, 3896 (2000t ACIEE Q. 'schiirer, S.C.,Gessler,S., Buschmann ''Sanford, M.S., Henling, L.M.. Da1. \l' -Bielawski, C.W., Louie, J., Grubbs.R I 'Maynard, H.D., Grubbs,R.H. Il {l. J 'Paquette,L.A., Schloss,J.D.. Efrenx-r

l 259 (2000). Wright, D.L., Schulte,J.P, Page.\l .\ Evans,P.,Gngg, R., Monteith. It rl I :Bujard, M., Briot, A., Gouverneur.\ . ! 'Trevitt. M.. Gouverneur,V.. Mios\orr 'Bujard, M., Gouverneur,V., Mioskorr 'Hoye, T.R., Promo, M.A. IL 40. lr-'9 ^Hanson, P.R.,Probst,D'A.. Robrn( \

l

>-N

/

Bn 93Yo

'Keck, G.E., Wager, C.A., Sell, T., Wager, T.T. JOC 64,2172 (1999). 2Keck,G.E., Wager,C.A. OL2,230'1 (2000). 3Keck, G.E., Wager, C.A., McHardy, S.F. 255, 11755 (1999). aMcAuley, B.J., Nieuwenhuyzen, M., Sheldrake,G.N. Ot 2, 1457 (2O0O). 5Knowles,H.S., Parsons,A.F., Pettifer,R.M., Rickling, S. f 56, 979 (2000). 6Guo, H., Zhang,Y. JCR(S) 342 (1999). 7Guo,H., Zhang,Y. SC30, 1879 (2000). oHanamoto,T., Shimomoto, N., Kikukawa, T., Inanaga, J.TAl0,295l (1999). eHonda,T.. Ishikawa.F. CC 1065 (1999). r0Honda,T., Kimura, M. OL2,3925 (200U. rrKato, Y., Mase, T. fL 40, 8823 (1999). 12zhv,I.-L., Shia,K.S., Liu. H.-J. TL40.'7055 ,]l99q). I3Kim, S.M., Byun, I.S., KLm,Y.H.ACIEE 39,725 (2000). raPedersen,H.L., Christensen, T.B., Enemaerke, R.J., Daasbjerg, K., Skrypdstrup,T. EJOC 565 ( 1999). rsYamashita,M., Okiyama, K., Ohhara, T., Kawasaki, I., Michihiro, Y, Sakamaki, K., Ito, S., Ohta, ,:Iggg\. s. cPB 47. 1439 'nMachrouhi,F., Namy, J.-L. TL 40, 1315 (1999). r7Lu,L., Chang,H.-Y., Fang,J.-M. JOC 64,843 (1999). r8Mukaiyama,T., tuai, H., Shiina,I. Cf 580 (2000). reRicci, M., Madariaga, L., Skrydstrup, T. ACIEE 39,243 (2000). 20Fukuzawa,S., Matsuzawa, H., Yoshimitsu, S. ./OC 65, l7O2 (20OO). 2rBaek,H.S., Yoo, B.W., Keum, S.R.,Yoon, C.M., Kim, S.H., Kim, J.H. SC30,31 (2000). 22zhou,L., Zhang, Y - SC 30, 597 (2000). 2rsakai,H., Hagiwara,H., Ito, Y, Hoshi, T., Suzuki,T., Ando, M. TL40,2965 (1999). 2aSono,M., Hashimoto,A., Nakashima,K., Tori, M. TL 41,5115 (2000). 25Caracoti, A., Flowers II, R.A. TL 41, 3039 (2000). r6Hsu,J.-L., Chen, C.-T., Fang,J.-M. OL2,1989 (2000). zTKunishima,M., Yoshimura,K., Nakata,D., Hioki, K., Tani, S. CPB 47,1196 (1999). 28Youn,S.W.,Park, H.S., Kim, Y.H. CC 2005 (2000). reHuang,Z.-2, Jin, H.-W, Duan, D.-H., Huang, X. JCR(S) 564 (1999). r0Ha,D.-C., Yun, C.-S.,Lee,Y. JOC 65,621 (2000). rrKan, T., Nara, S., Ozawa,T.,Shirahama,H., Matsuda,F. ACIEE 39,355 (2000). r2Kang,H.Y, Song,S.E. TL41,937 (2000). rrMolander, G.A., Machrouhi F. JOC 64, 4119 (1999). , taZhor,L.,Zhang,Y., Shi, D. S 9l (2000). r5Matsuda,F., Kawatsura,M., Hosaka,K., Shirahama,H. CEJ 5,3252 (1999). r6Aurrecoechea, J.M., Fananas, R., Arrate, M., Gorgojo, J.M., Aurrekoetxea, N. JOC 64, 1893 (1999\. r7O'Neill, D.J., Helquist,P. OL l, 1659(1999). rsDavid,H., Alfonso, C., Bonin, M., Doisneau,G., Guillerez,M.-G., Guibe,F. TL 40,8557 (1999). reJohnston,D., McCusker,C.F.,Muir, K., Procter,D.J. JCS(Pl) 681 (2000). r(rAurrecoechea, J.M., Fernandez,A., Gorgojo,J.M., Saornil,C. f 55,7345 (1999). llKatritzky, A.R.,Luo,Z-, Fang,Y, Feng,D., Ghiviriga, l. JCS(P2) 1375(2000). l2Tanaka,T., Wakayama, R., Maeda, S., Mikamiyama, H., Maezaki, N., Ohno, H. CC 1287 (2000). rrNandanan,8.,Dinesh,C.U., Reissig,H.-U.256, 4267(2000). 'oXu, F., Sun, J.-H., Yan, H.-B., Shen, SC 30, 1017 (2000). Q. asConcellon,J.M., Bernad, PL., Perez-Andres,J.A. ACIEE 38,2384 (1999). 'oKatritzky,A.R., Feng,D., Fang,Y. SZ 590 (1999). rTNishitani,T., Shiraishi,H., Sakaguchi,S., Ishii, Y. TL 41,3389 (2000).

F

Samarium(Ill) triflate

SamariumflIl) iodide. pAmino esters,l Promotedby SmIj the condensation of silyl ketene acetals with aldiminesis highly anti-selective.

on"* OSiMe3

ErO

Sml3

*

(*,,tn THF : OTBS An- p-anisyl

H N

NHAn I EtOOCv&.Ph

e{

: OTBS

)-sa6 ,

thioglycosides that are not acu valuable feature. rChang, G.X.,Lowary,T.L.OL 2.

Samarium(Il) trifl ate-nickdt Alkylations.l Samariumrtl taining catalytic amounts of H.

with NiI, for condensationof h

Go.=

rHayakawa,R., Shimizu, M. Cl,59l (1999).

triflate. Samarium(Il) iodidesamarium(IlD Reduction.t With this combination of reagents,methanol and base (KOH), reduction of carboxylic acids to primary alcohols is observed.Aldehydes are hardly affected.

Various reactions.t The b reaction, Mukaiyarna-aldol ra reaction, as well as the reductrr

rKamochi, Y.,Kudo,T.TL4l,341 (2000).

rCollin,J.,Giuseppone, N., l\lrtrr

isopropoxide. and nitroalkenes undergo condensation to afford 1,3,4+risubsti Imines firroleil tuted pyrroles. For the promotion of this reaction, samarium(Ill) isopropoxide is better than severalother Sm compounds and isopropoxides of lanthanum and ytterbium.

Scandium(Ill) triflate. lt. -1I i Allylation. When tetra.lllll pounds, the presenceof water I

Samarium(Ill)

(i-PrO)3Sm

.,]--r^*-

*

r',,/\r'*o'

IHF A

Aldol reactions. To condr water, the presenceof a surfat employed as surfactants.' ..\ h enol ethers,thereby increasing r

Vinylogous aldol reactrcxr alkenyloxiranes and aldehl dcs teric charactersin that thev beh

{ */:*\ 70To

o 'Shiraishi, S.,Ishii,Y f55, 13957(1999). T.,Nishihara, T., Sakaguchi, H., Nishitani,

Samarium(Ill) triflate. Glycosylation.r Samarium(Ill) triflate catalyzes the reaction of glycosyl 2-pyndyl sulfones with alcohols. This method is applicable to the preparation of di- and trisaccharides containing both furanose and pyranose residues. The difference in reactivity from

*\^*

I

Mannich reactions. F-.fu Sc(OTf)r-catalyzed condensarx taining a surfactant.5Under rlx imines in MeCN to provide p-e

ScandiumflIl)

rr..:!:r..rtionof silyl ketene acetalswith

triflate

thioglycosides that are not activated by the hard Lewis acid Sm(OTf)r is a synthetically valuable feature. rChang,G.X.,Lowary,T.L.OL2,1505(2000).

H N

\HAN

l o ^ : OTBS

- -'t-,/ -

o{

"'

Fonc :

Samarium(Il) triflate-nickel(Il) iodide. Alkylations.t Samarium(Il) triflate is prepared by reduction with Sm in DME containing catalytic amounts of Hg.'The solvated product is freed of solvent and combined with NiI2 for condensationofketones and acrylic estersto afford ylactones.

( F o L-J

nr. :Icthanol and base(KOH), reduction a.- \ldchydes are hardlY affected.

COOMe

Sm(OT02- Nil2 EtOH

\

f--t,ro-(o \-/\

Various reactions,t The binary salt is a very useful reagent for promoting Barbier reaction, Mukaiyama-aldol reaction, Michael reaction, Mannich reaction, Diels-Alder reaction,as well as the reductivecoupling ofcarbonyl compoundsand ofimines. rCollin,J.,Giuseppone, N., Machrouhi, F.,Namy,J.-L.,Nief,F. TL 40,3161(1999).

o . rJcnsation to afford 1,3,4-trisubstio:. ..rnrarium(lll) isopropoxideis better rc:. ,t lrnthanumand Ytterbium.

{

Scandium(Ill) triflate. 18, 3 I 7-3 I 8 ; 19, 3OO-302;20, 335-337 Allylation. When tetrallylgermane is used as the allylating agent for carbonyl compounds,the presenceof water in the reactionmedium is indispensable.r Aldol reactions. To conduct the Sc(OTf);catalyzed Mukaiyama aldol reaction in water, the presenceof a surfactantis very advantageous.2Calixarenesulfonatesalts can be employed as surfactants.i A hydrophobic microenvironment is created to protect silyl enol ethers,thereby increasing the yields of the products. Vinylogous aldol reactions leading to D-hydroxy-cr,P-unsaturatedaldehydesa from

I

alkenyloxiranes and aldehydesare promoted by Sc(OTf):. Such oxiranes possessamphoteric charactersin that they behaveas acceptorstoward allylborate reagents.

N--r

Ph/=/

\ 7lYo

tl S ..::rr.\'. f 55,13957(1999).

rlr.'r. rhe reaction of glycosyl 2-pyridyl le :,' the preparation of di- and trisacchas:.:-.. The difference in reactivity from

R^H

.of

SC(OTO3

-;;*

OH

' nt-* |

/cHo I

Mannich reactions. B-Amino ketones and esters are readily obtained from a Sc(OTf)j-catalyzed condensation of silyl enolates, aldehydes, and amines in water containing a surfactant.5Under the influence of Sc(OTf):, O-trimethylsilylnitronates add to imines in MeCN to orovide B-aminonitroalkanes.6

ScandiumflIl) triflate

Mechanistically related to the Mannich reaction is the formation of hydroxyarylglycine derivativesin a three-component reaction.T OH

OH

.

\

*o

!r)

NHAr

Sc(OTf)3- N.4gSOa

+ ArNH2 +

'.,A.oo*.

cH2cl2 25

Ttshchenka reaction. Reduction of B-hydroxy ketones with isobutyraldehyde while catalyzed by Sc(OTf)3 is stereoselective,anti-7,3-diol monoisobutyrates are the major products.s Cyclacondensation. A Prins-type reaction between aldehydesand 3-butenol leads to 4-tetrahydropyranolsand ethers.eSc(OTf).r assistsepoxide opening by an intramolecular attack of an enolate,resulting in the formation of three-, four-, and five-memberedrings.r0

) , t

? |

o t

't

Sc(OT03

7-

94To

tipurpose catalyst. Besides proflx{x Diels-Alder reactionand Meergern-

PhMe 25'

)t

)' ('

en\A,^oH

Scandium(Ill) tris(perfl uorullu DebenzylationI Benzyl e0rrs. cleavedby catalysisof Sc(CTf, r. Friedel-Crafts acylatian.: St-an

(Me3Si)2NLi

tr\

Secondary alkyl mesylates are adequate alkyl donors in this reaction.rr Both Sc(OTf)3 and TfOH can be used as the catalyst. It has also been reported that Sc(OTf)3 immobilized in ionic liquid forms a recyclable system for arene alkylation with alkenes.12 Friedel-Crafts

alkylation.

1,l-Diarylalkenes are formed in the reaction of areneswith l-phenylalkynes. Triflates of Sc. In, andZr aresuitablecatalysts.rr Hydrolysis.ta Esters bearing a coordinative group at a proximal position are hydrolyzed selectively under mild conditions, in the presenceof Sc(OTf)3.

o Z\A I

\.ry

ll

rlshihara, K., Hiraiwa,Y.,Yamamoro. ll rNishikido, J.,Yamamoto, F.,Nakarrmrt

Selenium. 18, 318; 20, 337 Alke ny lselenium compounds. alkenylzirconocene derivatives.Ttr 1 acetylated.2

Selcnides and diselenides.' 81 prepareeither RSeR' or RSeSeR'

o

),,,oRc -+

sc(orr)3 Z>A

MeoH- H2o

|

MeOH - H2O

ll

),,,oH

A--{\ I ll \.ry

BuLi + 2Se -

FoH

Silyl ethers.ts Silylation of alcohols at room temperatureusing methallyl(t-butyl)dimethylsilane as TBS group donor is catalyzedby Sc(OTf )3.

|rt

rAkiyama,T., Iwai, J., Sugano. \t. f 55. 2Manabe,K., Kobayashi,S. SL 5{7 r 199 rTian, H.-Y., Chen, Y-J., Wang. D,. Zrq alautens,M., Ouellet,S.G., Raeppel.S sKobayashi,S., Busujima,T.. Nagar arru 6Anderson,J.C., Peace,S., Pih. S. St S! THuang,T., Li, C.-J. TL 41,6715 r)U,t',t EGillespie,K.M., Munslow, I.J.. Sccn. P "Zhang,W.-C.,Li, C.-J. 256, 2.lO-1' l(n roCrotti,P.,Di Bussolo,V., Favero.L . \l rrKotsuki, H., Ohishi, T., Inoue. \1.. KqF r2Song,C.8., Shim, W.H., Roh. E.J . Ctn rrTsuchimoto,T., Maeda,T., Shiraltarr I ''Kajiro, H., Mitamura, S., Mori. A . Hrl; r5Suzuki,T., Watahiki,T., Oriyama. T l.I

Huang,X., Wang,J.-H..SC30,301rlCrI rHuang,X., Wang,J.-H.St 560(2ffi' 'Krief, A., VanWemmel, T.. Redon.\l . D

Selenium

r :::. Ii)rmation of hydroxYaryl-

p-.. $rth isobutyraldehydewhile ::: n{rl\obutyratesare the major r "..:cnrdesand 3-butenolleadsto r;r 'ncning by an intramolecular f, -.:-.,rndfive-memberedrings.rt) 1 l

'Akiyama, T., Iwai, J., Sugano,M. 255,7499 (1999). 2Manabe,K., Kobayashi,S. SI 547 (1999). 3Tian,H.-Y., Chen,Y-J., Wang, D., Zeng,C.-C., Li, C.-J. TL41,2529 (2000). alautens,M., Ouellet,S.G.,Raeppel,S. ACIEE 39,4079 (2000). sKobayashi,S., Busujima,T., Nagayama,S. SL 545 (1999) 6Anderson,J.C.,Peace,S., Pih, S. SL 850 (2000). THuang,T., Li, C.-J. TL 41, 6715 (2000). nGillespie,K.M., Munslow, I.J., Scott,P. TL 40,9371 (1999). ezhang, W.-C., Li, C.-J. T 56,2403 (2ffi0). 10Crotti,P, Di Bussolo,V, Favero,L., Macchia, F., Pineschi,M., Napolitano,E. f 55, 5853 (1999). lrKotsuki, H., Ohishi, T., Inoue, M., Kojima, T. S 603 (1999). r2Song,C.8., Shim, W.H., Roh,8.J., Choi, J.H. CC 1695(2000). lrTsuchimoto, T., Maeda, T., Shirakawa, 8., Kawakami, Y. CC 1573 (2000). 'uKajiro, H., Mitamura, S., Mori, A., Hiyama, T. BCSJ 72,1553 (1999). r5Suzuki,T., Watahiki,T., Oriyama,T. TL 41,8903 (2000).

Scandium(Ill)

tris(perfl uoroalkanesulfonyl)methides.

Debenzylationr

Benzyl ethers, N-benzylamides,

and benzyl ester(s) are efficiently

cleaved by catalysis of Sc(CTfj)3.

r

Frtedel-Crafts

-

acylation.2

Scandium tris(perfluorobutanesulfonyl)methide

tipurpose catalyst. Besides promoting

,ao, E:r- .irc adequatealkYl donors tn i- :r. catalyst.It has also been lt- ., rccvclablesYstemfor arene p. .i rth l-phenylalkynes.Triflates p .:' .r proximal Position are hYrl"- :Sc(OTf)r.

Diels-Alder

Friedel-Crafts

reaction and Meerwein-Ponndorf-Verlev

is a mul-

reactions, it is also useful in the reduction.

rlshihara,K., Hiraiwa, Y., Yamamoto,H. St 80 (2000). 2Nishikido,J., Yamamoto,F., Nakaiima,H., Mikami, Y, Matsumoto,Y., Mikami, K. Sf 1990 (1999).

Selenium. 18, 318; 20, 337 Alkenylselenium compounds. Selenium is easily inserted into the C-Zr bond of alkenylzirconocenederivatives. The products can be oxidized to dialkenyl diselenidesror acetylated.2 Selenidesand diselenides.t By manipulation of reaction conditions it is possible to prepareeither RSeR' or RSeSeR'.

3 ) ,OH

RX BuLi

+ 2Se

-

BuSe-SeLi +

BuSe-SeR

I err-i

Y

R'X

2 BuSeLi

t'\---\t

:F af -l

I:

BuSeR'

I >-oH

:c using methallyl(l-butYl)di-

rHuang,X., Wang,J.-H.SC30,301(2000). rHuang,X., Wang,J.-H.SL560(2000). rKrief, A., VanWemmel,T., Redon,M., Dumont,W, Delmotte,C. ACIEE38,2245(1999\.

Silica gel

Selenium-carbon monoxide. Ureas,' Nitroarenes undergo reductive carbonylation and the in situ trapping with unhindered secondaryamines leads to unsymmetrical ureas. Indoles.z 2-Nitrostyrenes afford indoles in the Se-catalyzed cyclization. The substratesinclude 2-nitrostyrene itself and various ct- and p-substituted homologues.

R

Se/CO Et3N - DMF

Itoh.A., Kodama.T.. Masakl.\'. 5f .r rDas,B., Venkataiah, 8., Madhusudl 'ltoh, A., Kodama, T.,Inagaki.S..\tr 'Baptistella, L.H.B.,Sousa, I.N|.O..Cr 'lwasawa, N., Sakurada. F..Iwamorol

100.

R = H .A r . . . . R ' = H . M e .. . .

rYang,Y, Lu, S. ?L 40, 4845(1999). 2Nishiyama, (1999). Y.,Maema,R., Ohno,K., Hirose,M., Sonoda, N. Zt 40, 5'71'7

Silicon tetrafluoride. 3-Fluoroalkanols.t Oxerarcs propargylic are opened by SiF. rr

additives. For example, good resu reaction seems to be suppresscdI promotingepoxideopening.

Silica gel. 15, 282: 18, 3 I 9; 19, 303-304; 20, 338-339 Selective reactions. Desilylation of triethylsilyl ethers in the presence of t-butyldimethylsilyl ethersis accomplishedwith a mesoporoussilica in methanolat room temperature.r Selective esterification of nonaromatic carboxylic acids using NaHSOa-silica in methanolhasalsobeendescribed.2 Oxidations. Photochemicaldegradationofa-hydroxy acids and phenylaceticacid derivatives(oxidativedecarboxylation)rtakesplacein the presenceof a mesoporoussilica. With acidic potassiumdichromate adsorbedon silica-zirconia,regioselectiveallylic oxidation is achieved.oThis reagentis better than CrO:-3,5-dimethylpyrazolefor oxidation of 1-menthenederivatives becausethe 3-keto products are largely absent.

f , )

R

Glycosylfluorides.2 Gllcals I tion of SiFaand an oxidant suchas acetate(HzO). In suchcases.a hnr

Fluorination.t Fluorinarron r SiF.,.The reagentcombinationals varenes. K2Qr2O7l ZrO2-SiO2

Ph

Diels-Alder reaction. Adsorption on silica gel of certain alkyne-Co2(CO)6 complexes that possessdiene and dienophile units separatedby a suitable distance serves to shift the equilibrium toward their cycloadducts, as compared with that in solution.5

Shimizu,M., Kanemoto,S., Nakah.rn :Shimizu, M., Nakahara,Y, Yoshrotr 'Tamura, M., Takagi,T., Quan. H.-D . !

Silicon tetrafluoride

'l:r: 1 rnd the in situ traPPingwith Sr ,.itrlvzed cyclization. The subhomologues. I .: -.ri-,.tituted

R' z

'-v-\

|\ , : . - A N >-R

lItoh,A., Kodama, T.,Masaki,Y. SL35'7(1999). 2Das,B., Venkataiah, B., Madhusudhan, P SL 59 (2000). 3ltoh,A., Kodama, T., Inagaki,S.,Masaki,Y. OL2,33l (2000). aBaptistella, L.H.B.,Sousa, I.M.O.,Gushikem, Y, Aleixo,A.M. ?4 40,2695(1999). 5lwasawa, N., Sakurada, F.,Iwamoto,M. OL2,871 (2000).

H

Silicon tetrafluoride. 3-Fluoroalkanols,t Oxetanesin which one of the o-positions is benzylic, allylic, or propargylic are opened by SiFa regioselectively. Also, the ring opening is influenced by J o . 5 7 l 7( 1 9 9 9 ) .

additives. For example, good results are obtained in the presenceof BuaNF, whereas the reaction seems to be suppressedby diisopropylethylamine-water, which is effective in promotingepoxideopening.

l!

i J::r.r\ in the Presenceof t-butylr, ,. .rlrca in methanolat room temrr-'. '.r1ic acids using NaHSOa-silica d: , , .rcidsand phenylaceticacid deh. :':..cnce of a mesoporoussilica. allylic ..,.1-./rrconia,regioselective lrt , : r-dimethylpyrazolefor oxidarr ... r. rre largelYabsent.

9r

t )

F. SiFa- Me2S + Et2O 0"

z-OH

,Y )

R

R

Glycosylfluori.des.2 Glycals are transforrnedinto glycosyl fluorides with a combination of SiFoand an oxidant such as 1,3-dibromo-5,5-dimethylhydantoin, phenyliodine(IIf acetate(HrO). In suchcases,a bromine atom or a hydroxyl group is also introduced. Fluorination.3 Fluorination of arylalkenes with xenon difluoride is enhanced by SiFa. The reagent combination also transforms aromatic aldehydes into difluoromethoxyarenes.

Ph P{-

SiFa- XeF2

;*;

Phr,/-F

pAr 7lYo

e . : .crtain alkYne-Co2(CO)ucomu:::.i hr a suitabledistanceseryesto r.::r:'rrcdwith that in solution.5

rShimizu,M., Kanemoto,S., Nakahara,Y. H 52, 117 (2000). rshimizu, M., Nakahara,Y., Yoshioka, H. JFC 97 57 (1999') , 'Tamura, M., Takagi, T., Quan, H.-D., Sekiya, A. JFC 98, 163 (1999).

Silver carbonate

Silver. Claisen reanangement.\ Together with KI in acetic acid, silver effects Claisen rearrangementof allyloxyanthraquinones. rSharghi, H.,Aghapour, G. JOC 65,2813(2000).

Silver acetate. Cycloaifulitions.t 1,3-Dipolar cycloadditions of isocyanoacetic esters are catalyzed by AgOAc. In the absenceof dipolarophiles, the estersdimerize to give imidazole-4-carboxylic esters.

P a l e ,P , C h u c h e I, . E J O C l 0 l 9 r l 0 0 l , rGyollai, V., Somsak,L., Szilagyi. L. n. I 'Hauser, F M . , Y i n , H . O L 2 . 1 0 4 5t l m ) ,

MeOOC AsoAc

MeOOC

^

+

cN^cooMe

>

\: N.4eCN

/-] \*'^cooMe H

I t

:

Silver nitrate. 18,320; 19,305--106.i

Cyclizatinn.t 2-Alkynylbenzorc Substitutedisocoumarinsare the malc

Carbonyl compounds from a4llir the a-amino nitrile derivativesof enel drolysisof the products.2

rGrigg,R., Lansdell,M.L, Thornton-Pett, M. Z 55, 2025(1999).

Silver carbonate. 2-Methylenetetrahydrofurans.t 4-Alkynols cyclize on exposure to silver carbonate. An oxygen functionality at the propargylic position has a remarkable acceleratingeffect.

-

-N'

LDA

t{c.

+

. :

Nc'a

I

\

/-o'

ry

BuCHO .zu::-,2:-

q

Ag2CO3 PhH 80'

Barbier reactian,3

A catalvtic am

action of benzylic halides with ArCHO

l-Amino sugars.z Displacement of an anomeric bromine atom by an acetamino group is achieved when glycosyl bromides are treated with silver carbonate in MeCN in the dark.

AcO

aOAc

nco\9$-coNH2 ncd A.

AcO aOAc As2co3 > nco$-\,.o' MecN ncd ,l,ro. 76Yo

Oxidation.r

Oxidation of a naphthol can go beyond the quinone stage.

tbrmed.

rBellina,F., Ciucci, D., Vergamini.P.. Rml r P i e r r e ,F . ,E n d e r s D , . fL40.5301 11999, 'Bieber, L.W., Storch,8.C., Malvestrrr.I . ,l

Silver(I) oxide. 18, 321; 20, 341 Coupling of l-alkynes.t The ft alkenyl and aryl halidesin THF ar (fl, 1 tivator.The salts.BuoNX (X : OH. Fr

rMori, A., Kawashima, J.. Shimada. T. S (2000).

Silver(I) oxide

r:- .r.rJ. silver effectsClaisenre-

Ag2C03- Et3N cH2ct2 25.

*r ..rfltrscetic esters a.fe catalyzed , .:.::rcrize to give imidazole-4-car-

rPale,P, Chuche,J. EJOC 1019 (2000). rGyollai, V., Somsak,L., Szilagyi, L. TL 40,3969 (1999). ' H a u s e rF , . M . ,Y i n , H. OL2,1045 (2000).

t,':.]OC

L-

/ \ \N'^cooMe H

Silver nitrate. 18,320;19, 305-306; 20,340 Cyclization.t 2-Alkynylbenzoic acids afford lactonesby the action of AgNO1. 3Substitutedisocoumarinsare the major products. Carbonyl compoundsfrom a-amino nitriles. A synthesisofct-hydroxy enonesfrom the a-amino nitrile derivativesof enals startsfrom alkylation with aldehydesand the hydrolysis of the products.2

'r c\posure to silver carbonate' , rrrarkableacceleratingeffect.

.) -N'

*"-\Z-

=-,O\

LDA

AgNO3

BUCHO

THF - H2O

83% overall

'a7 o 99o/o

ri

-:,'rnine atom bY an acetamino .,.'h rilver carbonatein MeCN in

-,1 i

aOAc

{-o ^rl - *-7--5''v'' I n^X auv NHAc 760/o

rn.: :hc qulnone stage.

OH

Barbier reaction.r A catalytic amount of AgNO. is important in the Zn-mediated reaction of benzylic halideswith ArCHO in buffer solutions(pH - l2) as lessbibenzylsare formed. rBellina,F.,Ciucci,D., Vergamini, P.,Rossi,R. 7 56,2533(2000). rPierre,F.,Enders, D. TL 40,5301(1999). 'Bieber,L.W, Storch,8.C.,Malvestiti, I., daSilva,M.F.f4 39,9393(1998).

Silver(I) oxide. 18, 321; 20, 341 Coupling of l-alkynes.t The Pd(0)-catalyzed reaction of terminal alkynes with alkenyl and aryl halides in THF at 60" proceedsin good yields when Ag,O is added as activator. The salts. BU4NX (X : OH, F) have similar effects. lMori, A., Kawashima, J., Shimada, T., Suguro,M., Hirabayashi, K., Nishihara,Y. OL 2,2935 (2000).

Sodamide

Silver tetrafluoroborate. 13,273-27 4; 18, 322 Cleavage of S-(2arimetfulsilyl)ethyl group.t Facile Ag(I)-mediated S-C bond cleavageis the basis for the use of the TSE group in thiol protection. The TSE-substituted thioglycosides are stable toward most reagents for carbohydrate transformations except the very strongly hard and soft Lewis acids and desulfonylating conditions, therefore their many applications can be envisaged. rGrundberg, H., Andergran,M., Nilsson,U.J.TL 40,1811 ( 1999). Silver tosylate-urea, Allylntion.t Silver tosylate is used in combination with urea, a Lewis base catalyst, to promote allylation of aldehydeswith allyltrichlorosilane. rChataigner, L, Piarulli,U., Gennari, C.TL40,3633(1999).

Desilylatian.2 The C-Sr I an aryltrialkylsilane suffers ro ammonia.

rChoppin, S.,Gros,P, Fon.\'. 5('. :Sun,G.-R.,He,J.-8.,Jie.H.-J..h

Sodium 13, 277; 18, 323--31{. Aromatic acylation.t .,\n , aromatic hydrocarbon such as boxylic ester in THF at room t DMF are used. Desulfunylation.2 A gena naphthalenide(Na + naphthala

Silver trifluoromethanesulfonate. 13, 274-27 5; 14,282-283; 16,302; 17,314; 18, 322-323; 19, 306; 20, 342 N-Alkylation.t Silver triflate is essentialfor an intramolecular alkylation of oxazole that contains an aziridine moiety. A I,3-dipolar cycloaddition is triggered henceforth.

OAc

OTBS AgOTf / N.4eCN

o

rPeriasamy, M., Reddy,M.R..Bh.i rBergmeier, S.C.,Seth,P.P.fL {0. (

'( )**" ( I

'Vede.is, 8., Klapars, A., Naidu,B.N.,Piotrowski, D.W.,Tucci,F.C."/ACS122,5401(2000). Sodamide.20,342 Alkylation.t Allyl phenyl sulfide undergoes alkylation using DME-activated sodamide.The processis adaptableto a synthesisof phenyl 1-vinylcycloalkyl sulfidesby a twofold alkylation with 1,rY-Ph 65%

is by s.r.1. of indole-3-acetonitrilesrs : : \ubstituted indoles are conveniently F .'.:hBurNF.'n r. ..- tirnyl) arylamines lose one of the r'relic disulfidesare obtainedfrom l,

Partial

hydrolysis,t

hydroxide.

20, 359

The partial hydrolysis

of dimethyl

esters can be achieved by

usingdry BuaNOHin THF or DME. rHasegawa, H. SL 84 (1999). T.,Yamamoto,

Tetrabutylammonium nitrate-trifl uoroacetic anhydride. Nitration.t This reagent system nitrates l-deazapurine nucleosides.The regioselectivitydependson existing substitutionpatterns. lDeghati,P.Y.F., M.J.,Koomen,G.-J.TL4l,569(2000). Bieraugel, H., Wanner,

Tetrabutylammonium peroxydisulfate, 19, 322 C:0 regeneration. Oximesl and semicarbazones2are cleaved. Oxidations, Benzyl ethers are removed by oxidation with (BurN)zS2Os and alcoholysis3.Primary amines are oxidized to nitriles with Ni-Cu formates as catalyst.a Oxidative cyclaadditian.5 The oxidation of l,3-dicarbonyl compounds in the Dresenceof cvclic enol ethersleadsto fused acetals.

410

Tetraethylammoniurn hydrogen carbonate

'Chen, F., Liu, A., Yan, Q., Liu, M., Zhang,D., Shao, L. SC 29, 1049 (1999). 2Chen, F., Liu, J.-D., Fu, H., Peng, Z.-2., Shao,L.-Y. SC 30, 2295 QUn). 3Chen, F., Peng,Z.-2., Fu, H., Meng, G., Cheng, Y., Lu, Y.-X. 5L627 (2000). aChen,F., Peng,Z.-2., Fu, H., Liu, J.-D., Shao,L.-Y. JCR(S)726 (1999). 5Chen,F., Fu, H., Meng, G., Cheng,Y., Hu, Y.-L. S 1091 (2000).

Tetraethylammonium peroxydicarbc Oxazolidin-2-ones.1 This reagc'n Et4NClOl, CO2, and 02. It carborrle cyclizationto oxazolidin-2-oneson iunl

rFeroci,M., Inesi,A., Muccianti.y.. ft1x.r [. Tetrabutylammonium tribromide. Ether cleavage.r BuaNBrj in methanol cleaves several kinds of ethers but TBS ethers are the most susceptible. Thus, desilylation can be achieved in the presence of acetonidesand THP ethers. rGopinath, R.,Patel,B.K. OL2,4177(2000).

i

?

Tetrabutylammonium triorganodifl uorostannates. Diarylmethanes.t With (PhjP)4Pd as catalyst, unsymmetrical ArCH2Ar' are obtained from a cross-coupling reaction between aryl triflates and BuqN[BnrSnFz] in DMF. Disulfides.z BuaN[RjSnF2] act as nucleophiles toward sulfur. Oxidative dimerization of the thiols initially formed, results in disulfides.

Tetrakis(acetonitrile)copper(I ) hexefr Cyclic imines.r Alkynylamine. cr Diaryl ethers.2 The phenol-anl (MeCN)aCuPF6.

Epoxidation.3 Conversionof alkcn ascatalystproceedsat low temperatureI c

rMuller,T.E.,Grosche, M., Herdtweck. F- P Kalinin,A.V.,Bower,J.F.,Riebel.P. Snros 'Andrus. M.B..Poehlein. B.W.Il 41. lri:: '

Tetrakis(triphenylphosphine )palledit 16,3 17-323: 17, 327-33 | : 18, 3{7--U9

rMartinez, A.G.,Barcina,J.O.,delR.C.Heras,M., deF.Cerezo, A. OL2, 1377(2000). 2Kerverdo, X., Poulain,S.,Gingras, M.TL41,5841(2000). S.,Femandez,

Allylic displacements. Neu trp substitutionare B-allyloxyacrylicc':rc'r carbonatesand sulfonatescontainherrc Regioselective displacement of allr lx

Tetrachlorophthalimide. Primary amines.t When used in the Mitsunobu reaction, the litle compound converts primary and secondaryalcohols into the conesponding protected amines.

allylsilanes.2Allenyonitriles are obtarncrlt

tlia,ZJ., Kelberlau, S.,Olsson,L., Anilkumar,G.,Fraser-Reid, B. SL 565(1999).

Tetracobalt dodecacarbonyl. Pauson-Khand reaction.t With cyclohexylamine as activator, catalytic amount of Coa(CO)12mediatesthe Pauson-Khand reaction in DME under CO. rKrafft,M.8., Bonaga,L.v.R.ACIEE 39,3676(2000).

Tetraethylammonium hydrogen carbonate. 20, 360 Carbonates.t Treatment of 1,2-diols with Et4NHCOT in MeCN at room temperatureresults in the formation of cyclic carbonates. Sulf.des.2 EI4NHCOj or (EtaN)2COjcan serve as basein the alkylation of thiols. rCasadei, M.A.,Cesa,S.,Feroci,M., Inesi,A. NIC 23,433(1999). 2Feroci, M., Inesi,A., Rossi,L. SC29,2611(1999).

t(

, t*

n_*R,, ocooR

Displacementthat is followed hr cr,

1-hydroxyalkyl-1-lactones.5 Thndem coupling and cvcli/ir c-arylvinylated cyclopropanes6 and trt andoxazolidinones." Furanderivatrrc.r

6\o tl C,rHru/

+ Ptrl

Tetrakis(triphenylphosphine)palladium(0)

4tl

Tetraethylammonium peroxydicarbonate. Oxazolidin-2-ones,t This reagent is available from electrochemical reaction of EqNClOl, CO2, and 02. It carboxylates 2-amino alcohols and the products undergo cyclization to oxazolidin-2-ones on further treatment with TsCl.

( :e r()19( 1999). P l:q: (1000). '-\ .i 627(2000). -th il9g9). f., - ' r t

rFeroci, V, Rossi,L.TL40,6059(1999). M., Inesi,A.,Muccianti,

r.. .c'\erll kinds of ethers but TBS n . i:l he achievedin the presence of

Tetrakis(acetonitrile)copper(I) hexafl uorophosphate. Cyclic imines.' Alkynylamines cyclize under the influence of (MeCN)aCuPF6. Diaryl ethers.2 The phenol-aryl halide coupling is promoted by Cs2COj and (MeCN)+CuPFc. Epoxidation.3 Conversionof alkenesto epoxideswith MCPBA, using (MeCN)aCuPF6 as catalystproceedsat low temperature(e.g., -20').

!5.

a.!.:. unsymmetricalArCH2Ar' are r:-. .:r\l triflates and BuaN[BnjSnF2] s ' .r,ird sulfur. Oxidative dimerization

\ OLz. 1377(2000)Cr-: < \ J t (2000). [ {r

lMuller,T.8.,Grosche, 8., Pleier,A.-K.,Walter,E.,Yan,Y-K. OM 19, 170(2000)M., Herdtweck, rKalinin,A.V, Bower,J.F.,Riebel,P, Snieckus, v. JOC 64,2986(1999). rAndrus. B.W.TL4l, l0l3 (2000). M.B..Poehlein. Tetrakis(triphenylphosphine)palladium(0). 13, 289-294; 14' 295-299; 15' 300-304; 16. 3 11 -323 : l7 . 327-33 | : 18, 347-3 49 ; 19, 324-33 | : 20, 362-3 68 Allylic displacements. New types of substrates for this (Ph1P)aPd-catalyzed substitutionare B-allyloxyacrylicestersand p-allyloxyvinyl sulfones.rThese vinylogous carbonatesand sulfonatescontainbetterleaving groups. Regioselectivedisplacementof allylic acetatesthat contain a homoallylic silyl group gives are obtainedby reactingpropargyl carbonateswith Me]SiCN.r allylsilanes.2Allenyonitriles

L(-: .u reaction, the litle compound ;, :::.ponding protectedamrnes. R-'

r i. .: u. Sr 565(1999).

R \

q,, ocooR

h:. :rl lrs activator, catalytic amount of I I ) \ 1 F -u n d e r C O .

' R (Ph.P)4Pd> R + Me3si_cN Fc{ rHF ^ Nc

at room

/'\n i l -

FL-:ti.r.

n: .i. basein the alkylation ofthiols. 3ri

..)99).

R-

Displacementthat is followed by cyclization enablesthe synthesisof chromenesaand l-^y-lactones.' 1-hydroxyalky Tandem coupling and cyclization. Functionalized allenes are converted to and heterocyclesincluding epoxides,Ttetrahydrofurans,E cr-arylvinylatedcyclopropanes6 Furanderivativesare formed from allenyl ketones.l0 and oxazolidinones.')

:h

rr:. F-I.NHCOr in MeCN

'

+Ph-l

(Ph3P)4Pd .------------------*

tn\-

/ \\ ^t;in,l'#.'c''H"404

CtzHzs 75%

4t2

Tetrakis(triphenylphosphine)palladium(0)

In the presenceof sodium alkoxide (for generating alkoxyimino nucleophiles for the cyclization), 2-alkynylbenzonitriles afford isoindole derivatives.| | Cyclizations and cycloadditions. Treatment of N,N'-diacylhydrazinesl2 and "y,6-unsaturated ketone O-pentafluorobenzoyloximesrr with (Ph.P)+Pdgenerates1,3,4oxadiazolesand substitutedpyrroles,respectively.

N

'ococ6Fs

(Ph3P)4Pd Et3N / DtVtF

pn)*

A [4 + 2]cycloadditionbetweenenynesand 1,3-diynes,with the latter serving as the two-carbon component,results in substitutedbenzenederivatives.The adductsderived from 1.4-di-l-butoxv-1.3-butadivne are readilv convertedto coumaranones.ra

I ) )

+

l

+ rPh ,^/*NHR

2 2 ,;i

z>zy\sna" (.o-*\.,/ | ll l" l

>:F .-':Dvs:

N1-'N'N-"\

93%

Addition to alkynes. Nucleophiles add to alkynes in different addition modes. are Thus, c-substituted vinylphosphonium saltsr6 and 1,2-diphosphonylalkanesrT prepared from 1-alkynes,but apparently an isomerization-hydroaluminationpathway prevails when 2-alkynes react with amines under similar conditions.The products are allylamines.r8(Note the formation of N-benzyl-2-styrylpiperidinein an intramolecular reaction,but the correspondingN{osyl derivativefails to cyclize.)

(-F*

Tetrakis(triphenylphosphine)palladium(0)

ai :ri .rlkoxyimino nucleophilesfor the II k' .:::rr atives. c:" , 't N.N'-diacylhydrazines12and *ith (Ph.P)rPd generates1'3'4r.-.

ph'V.\\$runr, / R=rs

+ (Ph3P)4Pd

\':,'o-Q

phZ-""""ttNHR

Bn

, i

-

HN\

r

;

l

l

81%

/

f,h--f,\'/

i ncs. with the latter serving as the - Jcrivatives.The adductsderived .J to coumaranones.la

/Y

rr=a

Acylations. 2-Alkynoic estersare made from l-alkynes and a chloroformic ester in the presenceof (PhiP)aPdand base(DMAP-1,2,2,6,6-pentamethylpiperidine)'re Stille coupting. The usefulness of tosylates in the Stille coupling facilitates preparation of arylcoumarin inhibitors of gyrase 8.20 Benzylic and allylic boronates are I readily obtained from RSnBuj and bromomethylboronates.2 The Stille coupling is acceleratedby CuCl. An effective system applicable to sterically congestedsubstrateshas been developed.22Preparationof functionalized dienesby homousing slightly different conditionsenablescompletion of a coupling of alkenylstannanes ( of )-wodeshiol.r' synthesis

o'/:-

?'

1

/..

91Yo

{Ph3P)4Pd> ..\3;\t"utt'

o''

I

ll

*

I

o"^"^J-..ttu'" bu3r,, I

ricr_cucrI

ll

I

I

95% (93% ee)

h \le,SiCN and then N-allYlation

o ) o

OH (Ph3P)4Pd>

CN

/- ' : .-rZ: ru. - N,f.f

O-4\Sne'.

(oJ=/

ll

P

:',"1"":::\o 82%

l1

93o/o

t,

f.\ncs in different addition modes. are .::rJ 1.2-diphosphonylalkanesrT pathway . :: zation-hydroalumination

.:rlrlar conditions.The products are . l - rr rr lpiperidine in an intramolecular .. to cyclize.) r( d,

(Yo., (-)-wodeshior

(o)""gd

Ho,"n,'oH

(ori)""to' 'o^'-/

Tetrakis(triphenylphosphine)palladium(0)

1-Alkynes are convertedto (E)-alkenesin a microwave-assisted hydrosilylation-Stille coupling process,2aand both reactions are catalyzed by (PhjP)aPd.Interestingly, arylation oftributylstannylacetylene is achievedvia a Stille coupling and then C-stannylation.25

Bu3Sn:

+ Ph-l

Ph:

##

+ Bu3Sn-l11-

T\e 2-azabicyclo[3.3.I ]nonane f accessiblefrom an intramolecular ccr Organobismuth dialkoxides cor.rp

pn-----sngu. 83%

_ R +

E( Stille coupling betweenRSeSnBuj and R'X is applicableto the synthesisof diorganyl selenidesRSeR'.26 Suzuki coupling, A practical transformation of ArX to ArMe is by the Suzuki coupling with [MeBO]..2? Diarylmethanes are obtained from ArCH2Br and arylboronic acids.28 The coupling of 3-pyrrolin-3-yl triflates with arylboronic acids leads to 3-arylpyrroles becauseof concurrentdehydrogenation.2e A caveatof the coupling involving haloanilines is that deamination30 also occursto someextent. A route to alkynylarenes and enynes from l-alkynes involves formation of alkynylboronic esters flithioalkynes * (r-PrO)rB] and Suzuki coupling in situ.:rrSuzuki cross-couplingusing thallium(I) ethoxide32 as promoteris superiorto TIOH becauseof its stability, commercial availability, and easeof use. A convenientmethod for assembling conjugatedpolyenesis assured.

A testimony to the efficiencl of , Pd-catalyzedreactions is delineatedr

,-Rr il It

+

(1) +

-a' r- l"n -

(1) = (Ph3P)aPd

COOMe - TtOEt (Ph3P)4Pd

t-BUOOC

THF - H2O (3 i 1)

tBuOOC

(Ho)28'V\y'2..v.oH

-J

I-BUOOC

97%

In a two-stagecoupling of N-allyl-N-2-bromoallylamine,the N-sulfonyl derivatives are most suitable as B-elimination of alkylpalladium intermediates after the initial (likely by coordinationl.t' intramolecularHeck reactionis suppressed The coupling of arylboronic acids with acid chlorides is the basis of a ketone synthesis.ra It is found that the Suzuki coupling in an ionic liquid has severaladvantages: reducedcatalystconcentration,no homocoupling,and reactionin the air.ts Other coupling reactions. A model study has demonstrated the utility of intramolecular Heck reaction in the construction of the morphine skeleton.l6 It is surprising that only the desirableregioisomer is formed.

F--

Tetrakis(triphenylphosphine)palladi,,m(0)

r . . - .\ .t\ e-assistedhydrosilylation-Stille Z . :

^

., Ph,P)1Pd.Interestingly,arylation :.lrns and then C-stannylation.2s

415

The 2-azabicyclo[3.3.1]nonaneframework, a portion of the strychnos alkaloids, is accessiblefrom an intramolecular coupling of 4-N-(2-haloallyl)aminocyclohexanones.3T Organobismuth dialkoxides couple with electron-deficient aryl and alkenyl triflates.38

LDA

Sn-l +

Ph:SnBu3

Tfo

R.-..-f

(Ph3P)4Pd

83%

NMP 80'

Etooc

| | ) EtOOC""--'J

:- :.eble to the synthesisofdiorganyl I'

: .{rX to ArMe is by the Suzuki

i ' : . : :J liom ArCH2Br and arylboronic

3'

A testimony to the efficiency of constructing highly unsaturatedcarbon skeletons by Pd-catalyzedreactions is delineated in a synthesisof xerulin.3e

^, 'r()nicacids leadsto 3-arylpyrroles : thc coupling involving haloanilines

^ ----J

)t' a

i-llkynes involves formation of .: Suzukicouplingin situ.rrSuzuki ,: r\ superiorto TIOH becauseof its \ ,r)nvenientmethod for assembling

ll

f

i

)

-

+lJfLn:+ ----J

BrZn.-:-

ll

I

II a u u : (1)= (Ph3P)aPd

| ,r, V "

TBS lrt

l(1) V

'-f\

_

tt_]\ -TBS

__/-:\,, I

'\r,

//--:--:l

___J

97To

r ., . ..rnrine,the N-sulfonyl derivatives lr.:.r .-:n intermediatesafter the initial ^. -,',,rdination).rr u -:ll,rridesis the basis of a ketone I .::.:,'nicliquid has severaladvantages: : i'.rctionin the air.rs r:.r. |(: demonctrated the utility of ,r the morphine skeleton.36It is

|r]

t"t'

:---1\

V

:-3uOOC

l,

l o n ;z n e 2 ;

Itl

: BuOOC

LBt

':1E'5

\:_Br

cp,z(H)cl

r-\:-',. V' +

Tetrakis(triphenylphosphine)palladium(0)

Rearrangements.

Allyl

esters are directly

converted

to isocyanatesaO when the

modified Curtius rearrangementis carried out in the presenceof (Ph.P)oPd.A versatile construction of the core structure of antibiotic CP-263114 is highlighted in a reaction sequenceconsisting ofcarbonylation, lactonization, and siloxy-Cope rearrangement.al

co

-

(Ph3P)4Pd

i-P12NEt / PhCN

bothZlEisomers useful

R

JEt3sio

46-56%

rEvans,P.A., Brandt,T.A., Robinson,J.8.TL40,3105 (1999). 2Macsari,I., Hupe,8., Szabo,K.J. JOC 64,9547 (1999). iTsuji, Y., Taniguchi,M., Yasuda,T., Kawamura,T., Obora,Y. OL2,2635 (2000). aNay, B., Peyrat, J.-F., Vercauteren,J. EJOC 2231 (1999). sRudler, H., Parlier, A., Cantagrel, F., Harris, P, Bellassoued, M. CC'17 | (2000). 6Ma, S., Zhao, S. OL2,2495 (2000). ?Ma, S., Zhao, S. JACS 121, 7943 (1999). 8Kang,S.-K., Baik, T.-G., Kulak, A.N. 5L324 (1999). 'Kang, S.-K., Baik, T.-G., Hur, Y. 255,6863 (1999). roMa, S., Zhang, J. CC 117 (2000). "Wei, L.-M., Lin, C.-F.,Wu, M.-J. TL 4l,1215 (2000'). I2lutun, S., Hasiak,B., Couturier,D. SC 29,111 (1999). rrTsutsui,T., Narasaka,K. CL 45 (1999). 'oGevorgyan,V, Quan, L.G., Yamamoto,Y.JOC 65,568 (2000). r5Gyoung,Y.S.,Shim, J.-G.,Yamamoto TL 41,4193 (2000). ,Y r6Arisawa, M., Yamaguchi, M. JACS 122,238'7 (2O0O). r T A l l e nJ, r . ,A . , M a n k e ,D . R . ,L i n , W . T L 4 l , l 5 1 ( 2 0 0 0 ) . rsKadota,L, Shibuya, A., Lutete, L.M., Yamamoto, Y. JOC 64,4570 (1999). reBottcher, A., Becker, H., Brunner, M., Preiss, T., Henkelmann, J., DeBakker, C., Gleiter, R.JCS(Pr)355s(1999). 2{)Schio, L., Chatreaux,F., Klich, M. TL 41,1543 (2000). 2rFalck,J.R.,Bondlela,M., Ye, J., Cho, S.-D. TL 40, 5647(1999). 22Han,X., Corey, E.J. JACS l2l,7600 (1999). 2rHan, X., Corey, E.J. OL l, 187| (1999). 2aMaleczka, Jr., R.E., Lavis, J.M., Clark, D.H., Gallagher,W.P.OL2,3655 (2000). 25Antonelli,E., Rosi, P.,Sterzo,C.L., Viola, E. JOMC 578,210 (1999). 26Nishiyama,Y., Tokunaga, K., Sonoda, N. OI 1, 1725 (1999). 27Gray,M., Andrews, I.P., Hook, D.F., Kitteringham, J., Voyle, M. TL 41, 6237 (2000). 28Chowdhury S., Georghiou, P.E. TL 40,'1599 (1999). 2el-ee,C.-W., Chung, Y.J. TL 41,3423 (2000).

r0Hird,M., Seed,A.J., Toyne,K.J. Sl {-rt 'r Castanet,A.-S., Colobert, F., Schlmarn ' 'rFrank, S.A., Chen, H., Kunz, R.K.. i-in

rrLee, C.-W, Oh, K.S., Kim, K.S...{hn- X IHaddach, M., McCarthy,J.R. IL $. -rl( '5Mathews, C.J., Smith, P.J.,Welton. T Cr '6Frey, D.A., Duan, C., Hudlicky. T. OL l. rTSole,D., Peidro,E., Bonjoch, J. OL 2. : rNRao,M.L.N., Shimada,S., Tanaka.\l ( reNegishi,E., Alimardanov,A., Xu. C Ot '"Okumoto, H., Nishihara, S., Yamanxro. 'rBio, M.M., Leighton,J.L. OL 2. 2905, 2

Tetrakis(triphenylphosphine)pelli Coupling reactions. c-Fluorrn virtue of their capacity of partakrng r based on the Pd(0)-catalyzed erct followed by the Negishi coupling :

1,2-Alkadien-4-ynesare fornrcd b with 1-alkynes.3

""" *",r(

*

\

'Chen, C., Wilcoxen, K., Zhu. Y.-F..KrmrDabdoub,M.J., Dabdoub,V.B., Manm.. 'Condon-Gueugnot, S., Linstrumelle. G I

Tetrakis(triphenylphosphine )pbttr Hydrosilylation. This reacuoo complexes such as (PhrP)1Ptor radrc

Dib oratio n of methy le necyc Iq opening of the substratesoccurs oo can be transformed in various * ar s tr

Tetrakis(triphenylphosphine)platinum(0)

when the . :.rc'ft€d to isocyanatesa0 (:: nrcsenceof (Ph3P)4Pd. A versatile :P-:hrll-l is highlightedin a reaction n .::1.:.lloxy-cope reiurangement.4l

\

-

l

I

:

= *^l

l

Et3SiO

417

3oHird,M., Seed,A.J., Toyne, K.J. SZ 438 (1999). 3rCastanet. A.-S., Colobert,F., Schlmam,T. OL2,3559 (2000)3zFrank.S.A., Chen,H., Kunz, R.K., Schnaderbeck, M.J., Roush,W.R. OL2'2691 (2000)' 3 r l e e . C . - W . .O h , K . S . ,K i m , K . S . ,A h n , K . H . O L 2 , 1 2 1 3 ( 2 0 0 0 ) 34Haddach, M., McCarthy,J.R. Zt 40, 3109 (1999). rsMathews, C.J., Smith, P.J.,Welton, T. CC 1249 (2000). r6Frey,D.A., Duan, C., Hudlicky, T. OLl,2085 (1999). rTSole,D., Peidro,E., Bonjoch, J. OL2,2225 (2000). r8Rao,M.L.N., Shimada,S., Tanaka,M. OL l, l2'l I (1999). ieNegishi,E., Alimardanov,A., Xu, C. OL2,65 (2000)' loOkumoto, H., Nishihara, S., Yamamoto, S., Hino, H., Nozawa, A.' Suzuki, A' Sf 991 (2000)' arBio, M.M., Leighton,J.L. OL2,2905 (2000).

l 46-56Yo

iodide. 18' 349-350; 20, 369 Tetrakis(triphenylphosphine)palladium(0)-1.n9,r6( 1999).

t \l l'( ) replaces the catecholboryl r: .: :.r()tectedform are obtainedfrom r .. :kup. tO the smooth autoxidation of .a!:.1:.1;

rFenaz,H.M.C., Grazini, M.V.A., Silva, Jr., L.F., Longo, Jr., L.S. SC 29, 1953 (1999)'

Thallium(IlD nitrate,TTN. 16,326;18,351;19,334;20,371 cyclopentyl 2-hyd.roxyalkylketones.t 2-(l-cyclohexenyl)ethanolsundergo nng with TTN in aqHOAc. on treatment contraction

r l' RuCll. Without TEMPO, further !i".::r

rl /\'\oAc

|

r|.

'

419

r(No3)3./\)-\/oH

c'd.

(-)--

c . : .. i n \

allylic alcohols to ketones

*ffi

|

v

H

,P oH y

R=H

71%

R=Me68%

Ring expansion.2 The ring expansion of unsymmetrical l-vinylcyclobutanols shows different regioselectivities as effected by Tl(NOj)j and by (PhCN)2PdC12'

Thionyl chloride-trifl ic acid

:Olah. G.A., Marinez, E.R., Prakash.G.K-S

Thiourea. 19, 336; 20, 37 l-372 Episulfi.des.t In a convenion ol dn(IV)-porphyrin complex, thiourea fu 1,3-Dioxolane cleavage.: Hl& thiourea in aqueous ethanol at rcflr substrates such as 1,2;5,6-di-O-rs acetonideis cleaved.

:Tangestaninejad, S.,Mirkhani,V. SCt. f, : Majumdar,S.,Bhattacharjya , A. JOC g. 5

Thulium(Il) iodide. Tml2(dme)1 is rnct Alkylation.' the reaction of RX with ketones. Il 13

o Tt(N03)3 (PhcN)2Pdcr2

6.3: 1 1 i 7.1

rFerraz, H.M.C.,Santos, A.P.,Silva,Jr.,L.F.,deO.Viera,T. SC30,751(2000). 2Kocovsky, P.,Dunn,V.,Gogoll,A., Langer,V. JOC 64,101( l 999).

1-Thionoacyl 6-nitrobenzotriazoles. Thiono esters.t At room temperature and in the presence of imidazole, the benzotriazolederivatives transfer the RC:S group to alcohols.

must be avoided.

rEvans, W.J.,Allen,N.T."IACS122.I I I t , i

Tin. 13, 298; 17' 333-334;18' 352. 2l Alkylation. The allylating agcl consistsof two species,the initialll- fc Tin in combination with Me.SrO : bromomethylketoneswith aldehldcs rChan,T.H.,Yang,Y.,Li, C.l. JOC6. sj rSun,P.,Shi,B. "/CR(S) 318(1999).

iShalaby, M.A., Rapoport, H. JOC 64, 1065(1999).

Thionyl chloride-benzotriazole. Chlori.des and nitriles. The reagent combinant transforms alcohols to alkyl chloridesand acidsto acid chlorides,rwhile aldoximesare dehydrated.2

Tin(II) bromide. 14' 303-304: l& -15 With SnBrl as prc Allylation.t regioselectivity and diastereoselectrrr

rChaudhari, S.S.,Akamanchi,K.c. SL 17630999). 2Chaudhari, S.S.,Akamanchi, K.c. SC29, 1741(1999\.

I

\4.,Bt Thionyl chloride-triflic acid. Dinryl sulfuxides.t A Friedel-Crafts-type reaction between arenes and thionyl chloride is catalvzed bv TfOH.

+ PhcHo

;

Tin[D bromide

rOlah, G.A., Marinez, 8.R., Prakash' G'K'S' St 1397 (1999)'

Thiourea. 19,336; 20,37 l-3'12 that is catalyzed by a Episulfides.t In a conversion of epoxides to episulfides atom' tin(Iv)-porphyrin complex, thiourea furnishes the sulfur I,3-Dioxolanecleavage.2Hydrolysisofcyclicacetalsisaccomplishedwith Some selectivity is shown in thiourea in aqueous ethanol at reflux temperature' in which the terminal substrates such as 1,2;5,6-di-O-isopropylidenefuranoses acetonide is cleaved' rTangestaninejad, S.,Mirkhani,V. SC 29,2079(1999)' 2Majumdar, A. JOC 9,5682 (1999)' S.,Bhattacharjya,

:l

Thulium(Il) iodide. in mediating Alkylation.t Tml2(dme)2 is more powerful than SmIz(thflx-HMPA HMPA where situation a in valuable particularly rhe reaction of RX with ketones. It is

v

must be avoided. IEvans,W.J.,Allen, N.T.JACS 122,2l I 8 (2000)'

-

A

\

"^A

Js --Ji._

r . l

le-nitrogen. 20, 380-391 ir. ::r. lbrmation of 2_substituted h,::. To obtain reasonableyields x . .rrlhdrawinggroup.

Reductive couprings'2 Ticlo-BuoNl appears to have similar reactivity as Ticl4-EtjN in effecting reductive coupling of ArCHo. Enolates generatedfrom ct-haloketonesby this reagentundergo aldor reaction with aldehydes, providing predominantrythe syn_rsomer. rTsuritani, T., Shinokubo, H., Oshima,K.TL40,gl2l (19991. 2Tsurirani, T., Ito, S.,Shinokubo,H., Oshima,X..lOi iS', SOIOtZOOOt.

fitanium(IV) iodide

Titanium(IV) chloridezinc. 20, 381 Reductive couplings. Formation of 4,5-diarylimidazolidines from imines is readily effected.l The reagent system for coupling ArcHO to afford syn-hydrobenzoinscontains TMEDA.23 (The complex is prepared from TiCla, Zn, TMEDA, and PbCl2. Note that an alternative complex for the same purpose is derived from TiCla, Mn, MerSiCl, and a Schiff base,but diastereoselectivitydependson the Schiff base.4)

rShimizu,M., Shibuya,K., Ha!aliaslrHayakawa, R., Sahara,T., Shimizu. V 'Mukaiyama, T., Yoshimura, N.. lganC lHayakawa,R., Shimizu, M. Ct 7lJ ,: iHayakawa, R., Shimizu, M. OL 2. rfr-

Titanium

OH

TiClai Schiffbase II

Ph

,nlYtn

,n\'n.

Mn - Me3SiCl

H

OH

N,leCN 25'

OH

13. j

tetraisopropoxide.

18,363-364;19, 346-34'l'.20. -1SI pAmino acid derivatives. i condensation.l

OH (99 : 1) 75%

rLi, J.,Wang,S.,Hu, J.,Chen,W. TL 40,196l(1999). 'Li, T., Cui,W., Liu,J.,Zhao,J.,Wang,Z. CC 139(2000). 3oshiki,T., Kiriyama,T., Tsuchida,K., Takai,K. CL334 (2O0O). aBandini,M.,Cozzi, P.G.,Morganti,S.,Umani-Ronchi, A. fZ 40, 1997(1999).

Titanium(Il) halide-copper. Reductive couplings,t Aliphatic and aromatic aldehydes undergo reductive dimerization on exposureto TiBr2-Cu. pHydroxy carbonyl compounds.2 Aldol and Reformatsky reactions involving debrominative enolization of cr-bromoketones and cr-bromo thioesters with TiCl2-Cu-r-BuCN are readily achieved.Acceptors are limited to aliphatic aldehydes becausepinacol formation by aromatic aldehydespredominatesunder the conditions. rMukaiyama,T., Kagayama, A., Igarashi,K. Cf 336(2000). 2Mukaiyama, T., Kagayama, A., Igarashi,K., Shiina,I. CL ll57 (1999).

Titanium(IV) iodide. Reductions. Chemoselectivereduction of sulfoxides to sulfidesr and a-diketones to a-ketols2employs the title reagentin MeCN at 0'. Aldehydes are dimerized to give l,2-diols (dl- >> meso-)on exposureto TiIa, with or without addingCu.r'a Aldol reactions,5 Methoxyallene oxide forms a titanium enolate on treatment with TiIa. Addition of aldehydesor acetalscompletes the aldol reactions.

o /\

Tict4 +

OMe

RcHo

o o H ,\^. OVe

,//Y'oMe

+

\

NHCOOMe

AUylic displacements. In R pronucleophileson treatment\r'lth I Aldol reactians. A high &E

reaction mediatedby titaniumrl\-r chiral ct-hydroxy acids, :rsymmetrx In conjunctionwith PhrP.rr-P( roalkyl ketones with aldehydes...1 the ketone by (i-PrO)oTi in the \lct

Ph

Fo*

(

t

)

H

rKise, N., Ueda,N. JOC 64,751I r 199 :Poli, G.. Giambastiani.G.. Mordrnr..|" 'Mahrwald, R. OL2,4011 (2000r {Shen,Y., Zhang,Y., Zhou, Y JCS,P i '

fi r-nium tetrrisopropondc

tl::r-r./olldines from iminesis readily ) : .::: 'rti rlrr-hydrobenzoins contains Z: l \!EDA. and PbCll. Note rhat an r.J ::,,m TiCl.,.Mn, Me.SiCl, and a S . : . . : :h l s e . ' t

OH l ' P h - -P: ' ' h

= ( l

:

)-

Shimizu,M., Shibuya,K., Hayakawa,R. SZ 1437 (2000). Hayakawa, R., Sahara,T., Shimizu, M. TL 41,7939 (2C0,O). \lukaiyama, T., Yoshimura, N., Igarashi, K. CZ 838 (2000). 'Hayakawa,R., Shimizu,M. CL724 (2000). ' Hayakawa, R., Shimizu, M. OL 2, 4079 (2000).

Titaniumtetraisopropoxide. 13,3 I 1-3I 3; 14,311-312;15,322;16,339;17,347-348; lE, 363-364;19, 346-347; 20, 381-382 pAmino acid derivatives. (l-PrO)aTiplays a critical role in the Mannich-type condensation.l

oH 39

1)

r

*

\orrae

)

i-Pr2NLi/ THF

\"oo""

-70"

COOMe

NHCOOMe

{r

di:

DJ

431

.-

NHCOOMe

lqqT{1999).

.i)dc-hydesundergo reductive

.{r'r(\rmatskyreactionsinvolving

s ::..1 cr-bromo thioesters with r( ,::i lrmited to aliphatic aldehydes ' P : , : :nlnatesunderthe conditions. {- :e99).

t\-.:r'. t() sulfides'and a-diketonesto ler-. ir. are dimerized to give l,2-diols H::: (-u.'{

Allylic displacements. In Pd(0)-catalyzed reaction, titanates generated from the pronucleophileson treatment with (i-PrO)oTi serve adequately.2 Aldol reactions. A high degree of syn-diastereoselectivityis exhibited in the aldol reaction mediated by titanium(IV) alkoxides in the presence of ct-hydroxy acids. With chiral a-hydroxy acids, asymmetric induction is observed.r In conjunction with PhrP, (i-PrO)aTi promotes condensationof bromomethyl perfluoroalkyl ketones with aldehydes.Allylic alcohols are obtained owing to the reducibility of the ketone by (l-PrO)aTi in the Meerwein-Ponndorf fashion.a

Ph

Fo*

(

Br

Ph - Ph3P (i-PrO)aTi --;"-

FaC

r :::.!ntumenolateon treatmentwith l-.: . r.'actions.

OH

-J*

3Me

syn : anti 3 0 : 7 0 9 2 : 8

no additive + (i-PrO)4Ti

\/-oli'

FsC

90To

'Kise, N., Ueda,N. JOC 64,7511 (1999). zPoli, G., Giambastiani, G., Mordini, A. JOC 64,2962 (1999). rMahrwald, R. OL2,4011 (2000). aShen,Y., Zhang,Y., Zhou, Y. JCS(P1) [r59 0999).

Titanocenebis(triethyl phosphite)

Titanocenebis(triethyl phosphite).20, 383 Desulfurativealkylationand acylation. Titanocene bis(triethylphosphite)promotes desulfurative alkylationof allylic sulfides(dithioacetals) with r-alkylhalides.r

tn-Yt) sJ

?tn Ph#spn

.

The cycloelimination is also ap apparently involving the releasr ol

Z;),.

Cp2TiIP(OEt)3]2

?' -ZYPn

Phs-^ Y'\ // ,Sph N-Bn ll

-

rHF 25"-^

PhS-(,./

.N-An

\--l

72Yo

Ph 73o/o

c RCH(SPh)CH:CHSPhI become liiJ(l $ith Cp2Ti[P(OEt)1],and Mg. hc' kctones.2Conjugated dienes and

-.-

rTakeda, T., Nozaki,N., Saeki,N., Fujiwara,T' TL 40' 5353(1999). 2Takeda, T., Taguchi,H., Fujiwara,T. TL 41,65 (2O0O). 3Takeda, T., Takagi,Y., Saeki,N., Fujiwara,T. TL 41,837'7(2O0O). 4Rahim,M.A., Fujiwara,T., Takeda,T. 5L1029(1999). sRahim,M.A., Fujiwara,T., Takeda,T. T 56,'163(2000). 6Fujiwara,T., Kato,Y.,Takeda,T. H 52,147(2000).

Titanocene dicarbonyl. 19, 347-348; 20, 384 Intramolecular ene reaction.t Enynes and dienynes undergo this cycloisomerization in the presenceof Cp2Ti(CO),

'*T)

-

.

\"'K

\

/

-' cooEt I ::.::r.lorms alcohols to nitriles t::r ..ic' rS activator and acetone

|.:.. l: .

S TL40,7355(1999).

nnane. r.:::: Sn-Li exchange(with BuLi), t::,philes. The (trimethylsilyl)r :::ric afterward.

OH - BF".OEI, BurSnH I - o^.1-r.r.^r.r-OH cH2ct2 I R

Aromatic aldehydes bearing an o-alkenyl substituent is reduced selectively when MejAl is added.3This selectivityis a manifestof chelativeactivation. Reductive amination,a A method for the conversion of carbonyl compounds to amines is by reaction with BujSnH and ammonium salts (derived from pnmary or secondaryamines) in DMF at room temperature. Hydrostannylation,s Regioselective hydrostannylation of several types of alkynes (to yield mainly ct-stannyl derivatives) is catalyzed by a molybdenum complex. rKamimura, K., Wada,M. TL 40,9059(1999). 2ooi,T.,Uraguchi, D., Morikawa,J.,Maruoka,K. OL2,2015(2000). rAsao,N., Shimada, T.,Yamamoto, Y. TL 41,9533(2000). aSuwa, T., Sugiyama, 8., Shibata, I., Baba,A. SL 556(2000). 5Kazmaier, U.,Schauss, D.,Pohlmann, M. OLl,l0l7 (1999).

Tributyltin hydrid*2,2' -azobis(isobutyronitrile). 19,353-357 ; 20, 391-394 D efunctionalizations. Heteroarenesulfonyl groups are reductively severed without affecting a geminal c-F bond.r A clean deoxygenation of alcohols via reduction of the corresponding thionocarbonatescalls for binding the tin hydride to a polymer and using trimethoxysilane to recycle the spent reagent.2 A method for synthesis of chiral cyclohexene derivatives from 4-substituted cyclohexyl halides involves derivatization to the Grignard reagent, reaction with menthyl (S)-2-bromophenylsulfinate, and then treatment with Bu:SnH, AIBN, and methylaluminum diphenoxide with irradiation by a sun lamp.3

n

Tributyltin hydride-2,2' -azobis(isobutyronitrile)

Amidoyl radicals uue generated from electron-richalkenesuch as enol deriraure.

""n\,\ \.',\*

fl? g^,*^."pn Group-transfer reactinns. A.Si- or P-linked aryl group separatedby five bonds to a carbon radical has the tendency to migrate to the carbon center.This reaction pattern can be exploited in a synthesisof 2-hydroxyalkylbiaryls from 2-bromobenzyl alcohols.a'5

R I

(Yo'\,

O ll- nr

Reductive cyclization, The Bu,Sn ensuingcarbonradicalsare liableto crch system.rr

[f\ao' %Ar

KF / H:O

A"lsi

BnOOC-N

\r This process is also applicable to arylation of secondaryaliphatic radicals,6and a carbon radical generated from O-S bond homolysis followed by radical transfer can be trapped.T

ar-l

OH

I I

w-'/

Cyclizations. Bromoarenes form radc cyclization routes to aporphines-indoldll

Ph

-\,.\ l

o-SAr

N-OBn

alkaloids.rl

Bu3SnH- AIBN/ PhH ;

,"\a"\

)-oe

R Bu3SnH- AIBN

%e,.

ph " P h- ^ r ' M"rsi'"''o I

oR

*

MeO

M&-y',

70o/o h eussnft-nlen

o

PhH

tl

'

o

----.t:-\ t / | l( |

fi-A.^on

L-J

MeO R

Bu3SnH- AIBN + PhMe r

I

MeO'\

*-./ R-\

R

R R 1,2-Migration of an acyl group to a nitrogen radical generatedfrom a-azido-B-keto estersto form amides(lactams)dis a pathway not observedin ionic reactions.

MeO MeO

t

I

r

A

r-"

MreoolNs

Bu3SnH- AIBN PhH

Bu3snH - AIBN PhMe

l

['/l€O\

rrc'

A

MeOOC 70To

MeO

R

Tritnvltiriydride-f2'-rtoDHisotrqmilrl"t

Ll

A m i d o y l r a d i c a | S a r e g e n e r a t e d f r o m a m i d o y l s e lqe n i d e s . I n t h e p r e s e n c e o f a n

electron-rich alkene such as enol derivative, addition occurs 3':S.H - AIBN + r,teAJl0Ph )2 \-

fl8

nv PhH

r. -' jl .eparatedbY five bondsto a e:-. - jnt!'r. This reaction pattern can 5 alcohols.a .'.hromobenzyl I :'

q^,*ot"pn

*

oR Aoa

o o o R ll il l

Bu3SnH- AIBN PhH A

ruVon

o

Reductivecyclization.TheBulSnradicaladdstoo.alkylaldoximesandthe groupr0 or conjugated ensuing carbon radicals are liable to cyclization with a carbonyl system.ll

K

I \'/-oH ...^Ar

t.

Bu3SnH-AIBN

BnOOC-N

\r

a#

PhH

\2,,

u 'NHBn

N-OBn 56lo

.1n aliphaticradicals,6and a car* cd by radical transfer can be

a. 1.

in synthesis,including cyclizations. Bromoarenesform radicals that can be exploited protoberberine-pavine and cyclization routes to aporphines-indolo[2,1-a]isoquinolines'r2 alkaloids.rl Ph

lr

\,\ -

MeO

MeO

0o/o Bu3SnH- AIBN

MeO :

I

- - .

PhMe A

R

MeO MeO R

i

MeO

R

K

T , il' l=3"" -.,1 eeneratedfrom ct-azido-p-keto rt'. ..'.1in ionic reactions. f:

*"oY)a\ ".o'YY

,a-\_ /-NH

ooc

70o/o

ftr Meo,\< OMe

""o6('l.fo Bu3snH.A,BN ^ PhN''!e veo'V\--l%orrre R=Me,cooR-620/o

Tributyltin hydride-2,2'-azobis(isobutyronitrile)

Ring closure is expected for a radical precursor set with an unsaturation four bonds away when such a compound is treated with BujSnH-AIBN. The versatility of such cyclizations is derived from allowance of many varieties of substitution patterns and heteroatomsbetween the reactive centers. Furthermore, as shown in a synthesisof 2,4-disubstitutedpyrrolidines,radiastereoselectivitymay be controlled in

Bu3SnH AIBN / PhH I

(

certain cases.

Phse) Ph._,\N,

Bu3snH-ArBN ai' rnr/*) ;;;*

a

R

. rnr/*)J

R

R

R=H 38 R = P(O)Phz 1

a,-.'\--

1

24

Bu:*

SiMe2Ph _\_ -SiMes

AlBri + r

"y-sultams,16 Basedon this method,expedientaccessto conjugatedexocyclic dienes,15 indoles.lTand ct-oximino-ry-lactonesr8 has beendevised. Also notable is the formation of a h 7,7-diyne.22 OH

/--\

pcPh3

fB,

( X . N -o_(

- AIBN Bu3SnH PhMe A

efi"

n

A

80%

The regioselectivity of cyclization through bond formation at either the ct- or r' B-position of a pyrrole dependson the electronic nature of the N-substituent.

ueo'y'-yt' l l V*Ao

R ,,N'.

A process involving cyclization-fra3l clopropanes23is a radical alternative to d 2-aminocyclooctenenitrile is formed in 56(

RN-1

Meolz\rA2 Bu3snH-ArBN \--l l + l l l l + Phi/e a \,A1rAo

Meo

NC

{^

SEM

SEM R=Me R = COOMe

43% 15Yo

-' LY^

Br

n=1.2.4 32o/o

Tandem cyclization is valued for synthetic efficiency. As illustrated, approachesto the BCD-ring segment of steroids2{)and a precursor of (*)-paniculatine2r are worth mentioning.

rWnuk, S.F.,Rios, J.M., Khan, J., Hsu. \'.-L ,l( 2Boussagnet,P., Delmond, B., Dumartin. G . R sImboden,C., Villar, F., Renaud,P. Ol l. 871 r aClive,D.L.J., Kang, S. ZZ 41, 1315 (2ffir sStuder,A., Bossart,M., Vasella,T. OL 2.9t5 t

Tfibutyltin hydride-2,2,-azobis(isobutyronitrile)

r .: r\tth an unsaturationfour r 11.- \nH AIBN. The versatility : - : " . \ a r i e t i e so f s u b s t i t u t i o n

Bu35nH

: : . i . . : t h r ' r m o r ea.s S h O w ni n a ) - : , , i r i l t \ m a y b e c o n t r o l l e idn

p

J

h

/

A I B N/ P h H A

74To \

SiMe2Ph

$*, K

SiMe2Ph

'.,.-\,,,".

1 24

Bu3SnH

SiMeq +

AIBN/ PhH A

d - ' . r e l r c d i e n e s , r1s- s u l t a m s , l 6

82o

(+)_paniculatine

Also notable is the formation of a bicyclo[3.1.1]heptaneskeleton from an acyclic 1.7-divne.22 OH

,^'vN \ l o\

Bu3SnH AIBN/ PhH

80%

Pi..,

A

Br > 85a/o

lltr)n at either the cr- or . ' . \ ' - s u b s t i t u e n t .I e

A process involving cyclization-fragmentationof 2-(o-bromoalkyl)-l,l-dicyanocycfopropanes23is a radical alternative to the Thorpe-Ziegler reaction of dinitriles. Thus, 2-aminocyclooctenenitrile is formed in 56Vo yield.

s

MeO

. I

\

-

il

Br

PhH ^

lH, I

NC_Yz\

L+4"

n=1.2.4

I

t

Bu"SnH- AIBN

32Yo

\. rllustrated,approachesto - -paniculatine2l are worth

rWnuk,S.F.,Rios,J.M., Khan,J.,Hsu,y-L. JOC 65,4t6g(2OOO). 2Boussagnet, P, Delmond,B., Dumartin,G.,pereyre, M.TL41,3377(ZOOO). 3lmboden, p. OL l,873 (1999). C.,Mllar,F.,Renaud, 4clive,D.L.J.,Kang,S. TL4t, l3t5 exn). sStuder, A., Bossart, M., Vasella, T. OL2,gg5 eOO}).

Tticarbonyl(pentamethylcyclopentadienyl)rhenium

oAmrein,S., Bossan,M., Vasella,T., Studer,A. JOC 65,4281 (2000). TPetrovic,G., Cekovic, Z. OL2,3'/69 '2OOU. sBenati,L., Nanni, D., Sangiorgi,C., Spagnolo,P.JOC 9,7836 (1999). 'Keck, G.8., Grier, M.C. SL 165'1(1999'). roNaito, T., Nakagawa, K., Nakamura, T., Kasei, A., Ninomiya, I., Kiguchi, T. JOC 64,2003 (Iggg). lrNaito, T., Fukumoto,D., Takebayashi,K., Kiguchi, T. H 51,489 (1999). r2Orito,K., Uchiito, S., Satoh,Y, Tatsuzawa,T., Harada,R., Tokuda,M. OL2,307 (2000). r3Orito,K., Satoh,Y, Nishizawa,H., Harada,R., Tokuda, M. OL2,2535 eO}U. raBesev,M., Engman,L. OL 2, 1589 (2000). r5Sha,C.-K., Zhan,Z.-P.,Wang, F.-S. OL2,20ll (2000). r6leit, S.M., Paquette,L.A. IOC 64,9225 (1999). rTTokuyama,H., Yamashita,T., Reding, M.T., Kaburagi, Y., Fukuyama, T. JACS l2l,37gl (Iggg). r8Clive,D.L.J., Subedi,R. CC 231 Q000\. leEscolano,C., Jones,K. TL 41,8951 (2000). 2oTomida,S., Doi, T., Takahashi,T. TL 40,2363 (1999). 2rSha,C.-K., Lee, F.-K., Chang,C.-J.JACS 121,9875 (1999). 2zBogen,S., Fensterbank,L., Malacria,M. JOC 64,819 (1999). 2rCurran,D.P..Liu. W. SL I l7 (1999).

Ttibutyltin hydride-triethylborane.15,333;16,350;17, 363-364;18,372; 20, 394 Cyclization,t Addition of BujSnH to B-allenyl-O-benzoyl oximes also causes cyclization.

)c"1

.

Bu3SnH- Et3B

\-N

SnBu"

\/Y

,n ,l\

|

!n P(

be'

t't">1, BulsnH-ArBN

'-;;;;*

+A Ph'

82Yo Radical additian.

rChen,H., Hartwig,J.F.ACIEE3t. -r,r9 Trichloroacetonitrile.

Hydroxyl protection.t Alcol reaction. Three sets of conditions I using DBU in MeOH, TsOH.H;( Zn-NHaCl in refluxing ethanol. Acid chlorides.: Sensitire rr treatment with Ph3P-CI.CCN ar roc

rYu,B., Yu,H., Hui,Y.,Han.X. Sl 75-r, rJang,D.O.,Park,D.J.,Kim, J. Il $. 5 TFichloronitromethane.

Dissulfides,t Treatment of r disulfides. ,l-Nitrosothiols are rhe rrr

bst 7 1o/o

\ /:c
( H

),,,OH

/

Ph 35 : 15) 44%

tf. .::. .rlkvl residueon reactionwith a g , ' . - :r r c l d s . T Ir .\ JOCU,803 (1999). x. : : ., 1999). F k,'.1 1899(2000).

Simmons-Smith reactian,4 A dramatic acceleration of the cyclopropanation by CF.TCOOHis probably due to formation of a more reactive speciesCFTCOOZnCH2I. rBouzide, A., Sauve, G.TL40,2883(1999). 2Kim,H.S.,Kim, T.Y.,Lee,K.Y.,Chung,Y.M.,Lee,H.J.,Kim, J.N.TL41,2613(2000). rKim, J.N.,Kim, T.Y, Lee,K.Y, Kim, H.S.,Kim, T.Y OL2,343 (2000). aYang,Z., Lorenz,J.C.,Shi,Y. 74 39,8621(1998).

Tiifl uoroacetic anhydride, TFAA. 18, 376-37 7 ; 19, 361; 20, 396-397 Dehydration. Endocyclic enecarbamates are prepared from the coresponding lactams via reduction and subsequentdehydration with TFAA-2,6-lutidine.l Regiochemically divergent lactonization processes of a hydroxynaphthoquinone derivativeinducedby TFAA and MerSiOTf are observed.2

)

cF3cooH

tL

I lt. .r75-376;20' 395-396 rr,,\ure to CF.TCOOH effectsthe ' .c. whileretaining the Primary

k'

OPMB

^ :

'v

l

,

/^o

--1 7 5o/o

:: rromatic aldehYdesand acrylic . i -hrdoxymethylcinnamic esters'2 i of an intervention to due :jrcntly -,,rides \ 4-hydroxyquinoline-3of t,'

a-aminoalkyl ketones,l The Dakin-West reaction using Trifluoromethyl TFAA-pyridine on N-substitutedd-amino acids affords the fluorinated ketones. Rearrangemenf. 2-Pyrrolidinemethanol derivatives undergo stereoselective ring expansionto give piperidin-3-ols.aCarboxylic acids are convertedto nitriless with one less carbon by TFA-TFAA-NaNO2.

Tiifluoromethanesulfonic acid (triflic acid)

Tr-rrr

Nitrodeboration.. lpso-substitution of arylboronic acids to give nitroarenes is accomplishedwith TFAA and NHaNOj. Reductive functionalization of (arylseleninyl)acetates.T when the pummerertype rearrangementof PhSe(o)CH2cooR is carried out in the presenceof a reactive silane (e.g.,

Dealkylation,5 Protodemethylation r! r ethyl group in the following reaction seqrrd

allylsilanes,MeqSiNs)carbon chain homologationor functionalizationof the estersresults. rOliveira,D.F.,Miranda,P.C.M.L., Correia,C.R.D.JOC 64,6646Oggg). 2Qabaja, G.,Perchellet, 8.M.,Perchellet, I.-P.TL4l, 3007(2000). 3Kawase, M., Hirabayashi, M., Kumakura, H., Saito,S.,Yamamoto, K. CpB 48,I l4 (2000). aCossy, J.,Dumas,C.,Pardo,D.G.EJOC 1693(l9gg). sSmushkevich, Y.I., Smushkevich, V.Y, Usorov,M.I. "/CR(S/tj2'l (lggg). 6Salzbrunn, S.,Simon,J.,Prakash, G.K.S.,Petasis, N.A.,Olah,G.A.Sa 14g5(2000). TShimada, y.ZZ 41,4637(2OOO). K., Kikuta,Y.,Koganebuchi, H., Yonezawa, F.,Aoyagi,S.,Takikawa, N-(T[ifl uoroacetyl)succinimide. Trifluoroacetylation.t Alcohols, phenols, and amines are acylated by the title reagent(14 examples,83-997a). rKatritzky, A.R.,Jang,B., Qiu,G., Zhang,Z.S 55 (1999). 21212-Triflioroethyl

carbamates. ureas,t The carbamates RNHCooCH2cFs are obtained by an electrochemical reaction of primary amides (RCoNHr) in cFjcH2oH. They undergo aminolysis to afford unsymmetrical ureas. rMatsumura, Y, Satoh,Y.,Onomura, O.,Maki.T. JOC 65.1549(2000). Tlifluoromethanesulfonic acid (triflic acid). 14, 323-324;15,339; 18,377;19, 362-363:20,398-399 Allylation.t Triflic acid is capableof catalyzingthe reactionof allyltributylstannane with aldehydes(not ketones) in water. Michael reaction.2 For conducting a Michael reaction of g-ketoesters with conjugated esters and ketones at room temperature under solvent-free conditions, triflic acid is useful. cyclizations. A stereocontrolled synthesis of trisubstituted tetrahydropyrans by condensationof homoallylic alcohols with aldehydesis developed.3Treatmentof rHp ethers derived from unsaturatedalcohols with triflic acid leads to oxygen heterocycles.a

CI".L,-O

cF:So:H'r"tb 65To

rhazinilam

I Loh, T.-p., Xu, J. TL 40, 2431 (1999). 2Kotsuki, H., Arimura, K., Ohishi, T., Maruzasr RrCloninger,M.J., Oveman,L.E. JACS l2l. l09l , I aDixon, D.J., Ley, S.V.,Tate,E.W ./CS(P/r 183 , I 5Johnson,J.A., Sames,D. JACS 122,6321 (?Vnl

T[ifl uoromethanesulfonic

anhydride

t triffc

15, 339-340; 16, 357-358; 18, 377 -37 8 : l).'. Nitrile oxide generation.t O-Silllaod precursors of nitrile oxides, by virnr of Tf2o-EtjN.

1,3,4-Oxadiazoles.2 Tf2O-pyridine rs : diacylhydrazines.

'Muri, D., Bode,J.W.,Carreira, E.M.OL 2. 5-t9r! 2Liras,S.,Allen,M.P.,Segelstein, B.E..tCgl. r_r: ,

Tfifluoromethanesulfonic anhydride (triflic anhydride)

.rcids to give nitroarenes rs

).:. tue\.

Dealkylation.s Protodemethylation is the key to functionalization of an unactivated ethyl group in the following reactionsequence.

When the Pummerer-type

r. :r-c.\enceof a reactive silane (e.g., c:..,r.rlizationof the estersresults. !-:'

COOMe

1999).

l l

r:

K. CPB48.I 14(2000). cFlso3H

-_- re99). : h (. \.t1.1485(2000). S .

cH2ct2

Irliikawa,Y.TL41,4637QUn).

cFlcH'oH

a:r'.::',d\are acylated by the title

70"

I

I

I V

COOMe N

I ^r.irned by an electrochemical 1'. . undergoaminolysisto afford

.t.

_ rx)t.

. : : r 1 5 ,- 3 3 91;8 , 3 7 7 ; 1 9 , hr :J.icrionof allyltributylstannane :, --'.retion of B-ketoesterswith t"r-: ., )lvent-freeconditions,triflic

by u:...^.riruredtetrahydropyrans :. .:-'\!'loped.r Treatment of THP tr . .,.i.t()oxygenheterocycles.a

I Loh, T.-P., Xu, J. TL 40, 2431 (1999\. 2Kotsuki, H., Arimura, K., Ohishi, T., Maruzasa, R. JOC 64,37'10 (1999). 3Cloninger,M.J., Oveman,L.E. JACS l2l,lO92 (1999). aDixon, D.J., Ley, S.V.,Tate,E.W. JCS(PI) 1829 (2000). 5Johnson,J.A., Sames,D. JACS 122,6321 (2OOO).

Tiifluoromethanesulfonic

anhydride

(triflic

anhydride).

13, 324-325;14,324-326;

15, 339-3 40; 16,357-3 58; 18,371-37 8; 19, 363-365; 20, 399 Nitrile oxide generation.t O-Silylatedhydroxamicacids are identifiedas stable precursorsof nitrile oxides, by virtue of their susceptibilityto transformationby Tf2O-EtrN. 7,3,4-Oxadiazoles.2 Tf2O-pyridineis a mild reagentfor the cyclodehydration of diacylhydrazines. tMwi, D.,Bode,1.W.,Canetra, E.M.OLZ,i3g (2N0. 2Liras, 5., Allen,M.P.,Segelstein, B.E.SC30,437(2N|D.

(Tiifl uommethyl)trimet}ylsilane

Tlifluoromethanesulfonyl azide. Diazocarbonyl compounds.l The title reagent is particularly useful for the introduction of an ct-diazo group to cr-nitro carbonyl compounds.

IBlazejewski,J.-C.,Anselmi,8.. \'\'ilmshun rlshizaki,M., Hoshino,O. Z56. g8l-rrl[fJrr

rCharette, A.B., Wurz,R.P, Ollevier,T. JOC 65,9252(2O0O).

Tii-2-furanylgermanFtriethl'lborer Organotrul Defunctianalimtion.t with this reagentvia radical intermedrrc

3-(Tiifluoromethanesulfonyloxy)-3-trifluoromethylpropeniminium triflate. 2-Trifluoromethylquinolines.r Reagent 1 transforms arylamines into 2-trifluoromethylquinolines in one step.

G"',.

Me2N

rfo83% (1)

I Baraznenok, I.L., Nenajdenko, V.G.,Balenkov a, E.S.EJOC937(1999).

; )

I Ia

t 7

a"

if NaBH4is usedin conjunction. rNakamura. H., Shino\utr..ll T..Yorimitsu,

Tiiisobutylaluminum. 19, 367--16.q Reductive rearrangement Errcr enol ethers establishes a horrxrk ATCHTOC(=:CH2)Meto ArCH:CH :CH Carbocyclesare formed on subjecuq

Claisen realrangementfollowed br rod one step.3

2-(TFifluoromethanesulfonyloxy)vinyl aryliodonium trifl ates. Aryliodonium salts.t Unsymmetrical diaryliodonium triflates and aryl(a1kyny1)iodonium triflates are readily synthesizedfrom the title compounds by reaction with ArLi and alkynyllithium reagents,respectively.Ethylene is one ofthe byproducts. +

Ar-l-A/ Ar-l Tfo

i_

Tfo-

OTs

-a Ar-l:R Tfo-

rPirguliyev, N.Sh.,Brel,VK., Akhmedov, N.G.,Zefirov,N.S.S 81 (2000). S-TFifluoromethyldiarylsulfonium trifl ates. Trifluoromethylation. These reagents are prepared from ArS(O)CF.,. They donate the trifluoromethyl group to suitable nucleophiles (e.g., arenes).

rdu Roizel, B., Sollogoub,M., Pearce..{J - i rSollogoub,M., Mallet, J.-M., Sina1.P .{Clt 'Wang, W, Sollogoub,M., Sinay.P. ACIEE

rYang,J.-J.,Kirchmeier, R.L.,Shreeve, J.M.JOC 63,2656(1998).

(Tiifl uoromethyl)trimethylsilane. I 5, 34 | ; 18, 378-37 9 ; 19, 366-367 ; 20, 400 Trifluoromethylation. Imines show similar reactivity as carbonyl compounds in accepting the MejSi and CF3 groups from MesSiCFj.r In the presenceof CsF of KF, the title reagentconverts l-alkynes to alkynyltrimethylsilanes.2

I -Ttiisopropylsiloxy- 1,2-propadicc Acrylic acid a-anian equivalcat the title compound with t-Buli rn Tl alkylated.Quenchingwith aldeh!desg

--15-, rStergiades, I.A.,Tius,M.A. JOC61.

1-T[iisopropylsiloxy-1,2-propadiene 451

:. particularly useful for the lr':la()Unds. ni

) lpnrpeniminium triflate. s: ::r\ arylamines into 2-trifluoro-

lBlazejewski, J.-C., Anselmi, E., Wilmshurst, M.P. TL 40, 5475 (1999). 2 l s h i z a k iM , . , H o s h i n o ,O . 2 5 6 , 8 8 1 3 ( 2 0 0 0 ) .

Tii-2-furanylgermanFtriethylborane. Defunctionalizatian.t Organobromides,iodides, and xanthatesare defunctionalized with this reagentvia radical intermediates.Only catalytic amount of the germaneis required if NaBH4is usedin conjunction. rNakamura, T.,Yorimitsu, H., Shinokubo, H., Oshima,K. SZ 1415(1999). Ttiisobutylaluminum. 19, 361-3 68 Reductive reanangemenf. Extension of the previously discovered reaction to enol ethers establishes a homologation route for alcohols, for examples., ATCH2OC(:CH2)Me to ATCH2CH2CH(OH )Me.I Carbocyclesare formed on subjectingunsaturatedS-, Se-, and C-glycosidesto r-Bu.1Al.2 Claisen rearrangementfollowed by reduction of the resulting ketones is accomplishedin

'_:-

.999).

one step.3

n triflates, triflatesand ary1(alkynyl)I::-:r le . npounds by reaction with ArLi r':: ,l the byproducts.

r

o-OH 57% + p_OH38%

:'-l:-A/ Tfoi-Bu3Al

Ar-l----E-R

BnO

).

OBn

96%

:000).

- i:i:lL'\

l

eno"')-ion

Tfo-

r.J rr()m ArS(O)CFj. They donate

._^\ t

rduRoizel,8., Sollogoub, M., Pearce, A.J.,Sinay,P CC 1507(2000). 2Sollogoub, M., Mallet,J.-M.,Sinay,P.ACIEE39,362(2000). rWang,W, Sollogoub,M., Sinay,P.ACIEE39,2466(2N0).

lw.

l-" 19.366-367;20,400 r1:.:l\ as carbonylcompounds in : I: rh!'presence of CsFof KF, the aa-

1-TFiisopropylsiloxy- 1,2-propadiene. Acrylic acid a-anion equivalent.t O + C Silyl migration occurs on treatment of the title compound with t-Bul-i in THF at -78'. The ensuing lithium enolate can be alkylated. Quenching with aldehydesgeneratesBaylis-Hillman adducts. rStergiades, I.A.,Tius,M.A. JOC 64,7457(1999).

Thimethylaluminun

T[iisopropylsilyl triflate. 20, 4Ol This reagent is a valuable component of [4 + 3] 2-(Triisopropylsi.lory)acroleinl by prepared from 2-methoxy-2-methyl-1,3-dioxan-5-one It is conveniently cycloadditions.

Diels-Alder reaction.u The Drelr-A stereoselectiveon using Me,Al to tether h each of which contains an allylic hydrorr 5

reaction with i-Pr:SiOTf-Et3N.

rKurosu.M. TL 41,591(2000). rAbe.N., Hanawa, \t \ H., Maruoka,K.. Sasalit. rSchneider. J.TL 4l' j04-1(lffrl C..Brauner, aBertozzi, F.,Olsson,R.,Frejd,T. OL 2. I lti '-lI

o

A

i-Pr3Si-/.\ i-Pr3SiOTf- Et3N

x;"

i

r'Yo

*;-

H

Silyl carbamates.2 Primary and secondary amines are protected as triisopropoxycarbonyl derivatives on consecutivetreatrnentwith carbon dioxide (EtrN--CH2Cl2,-78') and i-PqSiOTf. The silyl carbamatesare decomposedby BuaNF at ice temperature.

Ttimethyl orthoformate. Methyl 7,7-dimethoxyalkanmtcsHC(OMe)3-MeOH in the presenceof T