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Titolo:
TELLURIUM IN ORGANIC-SYNTHESIS - PREPARATION OF Z-VINYLIC CUPRATES FROM Z-VINYLIC TELLURIDES AND THEIR REACTION WITH ENONES AND EPOXIDES
Autore:
TUCCI FC; CHIEFFI A; COMASSETO JV; MARINO JP;
Indirizzi:
UNIV SAO PAULO,INST QUIM,CAIXA POSTAL 26077 BR-05508 SAO PAULO BRAZIL UNIV SAO PAULO,INST QUIM BR-05508 SAO PAULO BRAZIL UNIV MICHIGAN,DEPT CHEM ANN ARBOR MI 48109
Titolo Testata:
Journal of organic chemistry
fascicolo: 15, volume: 61, anno: 1996,
pagine: 4975 - 4989
SICI:
0022-3263(1996)61:15<4975:TIO-PO>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
HIGHER-ORDER; ORGANOTELLURIUM COMPOUNDS; ORGANOCOPPER CHEMISTRY; GRIGNARD-REAGENTS; CARBON-MONOXIDE; HYDROZIRCONATION-TRANSMETALATION; DIPHENYL DITELLURIDE; CONJUGATE ADDITION; ONE-POT; ACETYLENES;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
119
Recensione:
Indirizzi per estratti:
Citazione:
F.C. Tucci et al., "TELLURIUM IN ORGANIC-SYNTHESIS - PREPARATION OF Z-VINYLIC CUPRATES FROM Z-VINYLIC TELLURIDES AND THEIR REACTION WITH ENONES AND EPOXIDES", Journal of organic chemistry, 61(15), 1996, pp. 4975-4989

Abstract

Z-Vinylic tellurides, obtained with 100% stereoselectivity by the hydrotelluration of acetylenes, are easily transformed into Z-vinylic higher order cyanocuprates by reaction with preformed Me(2)Cu(CN)Li-2, n-Bu(2)Cu(CN)Li-2, or n-Bu(2-Th)Cu(CN)Li-2, with total retention of the double-bond configuration. The resulting vinylic higher order cyanocuprates react with unhindered enones to give the corresponding 1,4-addition products in good yields. Reaction of the vinylic higher order cyanocuprates with monosubstituted epoxides at 0 degrees C gives the homoallylic alcohols resulting from the attack to the less-substituted carbon atom, while the disubstituted epoxides failed to react. Allylic epoxides react at -78 degrees C with the vinylic higher order cyanocuprates to give mixtures of 1,2- and 1,4-opening products, the 1,4-product predominating. In all cases the double-bond configuration of the original vinylic telluride was preserved. The vinylic cuprates derived fromsimple vinylic tellurides and conjugated 1-telluroenynes react with epoxides at 0 degrees C, while vinylic cuprates derived from conjugated1-tellurodienes required the addition of 1 equiv of BF3 . Et(2)O to give the homoallylic alcohols on reaction with epoxides. The opening ofoptically pure epoxides through tellurium/copper transmetalation is stereospecific, giving one single stereoisomer of the corresponding homoallylic alcohol.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/10/20 alle ore 11:56:57