Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
DEBROMINATIONS OF VIC-DIBROMIDES WITH DIORGANOTELLURIDES - 1 - STEREOSELECTIVITY, RELATIVE RATES, AND MECHANISTIC IMPLICATIONS
Autore:
BUTCHER TS; ZHOU F; DETTY MR;
Indirizzi:
SUNY BUFFALO,SCH PHARM,DEPT MED CHEM AMHERST NY 14260 SUNY BUFFALO,SCH PHARM,DEPT MED CHEM AMHERST NY 14260 SUNY BUFFALO,DEPT CHEM AMHERST NY 14260
Titolo Testata:
Journal of organic chemistry
fascicolo: 1, volume: 63, anno: 1998,
pagine: 169 - 176
SICI:
0022-3263(1998)63:1<169:DOVWD->2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
ORGANOTELLURIUM(II) COMPOUNDS; VICINAL DIBROMOALKANES; TELLURIUM REAGENTS; STEPWISE MECHANISM; OXIDATIVE ADDITION; ORGANIC-SYNTHESIS; DISELENIDES; COMPLEXES; MILD;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
48
Recensione:
Indirizzi per estratti:
Citazione:
T.S. Butcher et al., "DEBROMINATIONS OF VIC-DIBROMIDES WITH DIORGANOTELLURIDES - 1 - STEREOSELECTIVITY, RELATIVE RATES, AND MECHANISTIC IMPLICATIONS", Journal of organic chemistry, 63(1), 1998, pp. 169-176

Abstract

Debrominations of cic-dibromides with diaryl tellurides 1-4 and di-n-hexyl telluride (9) are described. A mechanistic explanation of the debromination is offered which accounts for several key experimental observations: (1) the reaction is highly stereoselective with erythro-dibromides giving trans-olefins and threo-dibromides giving cis-olefins, (2) the reaction is accelerated by more electron-rich diorganotellurides, (3) the reaction is accelerated in a more polar solvent, (4) the reaction is accelerated by the addition of carbocation-stabilizing substituents to the carbons bearing the bromo substituents, and (5) erythro-dibromides are much more reactive than threo-dibromides, It is proposed that bromonium ion formation from the vic-dibromide is slow and rate-determining. Bromonium ion formation is followed by rapid scavenging of ''Br+'' by the diorganotelluride. The bromonium ion formation provides stereoselectivity and eclipsing interactions lower the reactivity of threo-dibromides. No intermediate species were observed by H-1 NMR.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 12:48:14