Rhodium-mediated cyclopentane construction can compete with .beta.-hydride elimination: synthesis of (.+-.)-tochuinyl acetate
摘要:
Rhodium(II) carboxylate catalyzed C-H insertion to form a cyclopentane is shown to compete effectively with beta-hydride elimination, except when the beta-hydrogen is ternary. Cyclization of diazo ester 27 gives 28, which is converted in three steps to (+/-)-tochuinyl acetate 25. Both the cyclization to form 28 and the alkylation of 28 proceed with remarkable diastereoselectivity.
Alkynes were selectively reduced to cis-olefins under mild conditions by Sml2 in admixture with first-row transition metal catalysts and appropriate proton donors, in which the corresponding transition metal hydrides are presumed as the reactive species. The conditions also effected the conversion of 1,6-diynes to the corresponding five-membered carbocycles.
CUVIGNY T.; HERVE DU PENHOAT C.; JULIA M., RECL. TRAV. CHIM. PAYS-BAS, 105,(1986) N 10, 409-421
作者:CUVIGNY T.、 HERVE DU PENHOAT C.、 JULIA M.
DOI:——
日期:——
Rhodium-mediated cyclopentane construction can compete with .beta.-hydride elimination: synthesis of (.+-.)-tochuinyl acetate
作者:Douglass F. Taber、Michael J. Hennessy、James P. Louey
DOI:10.1021/jo00028a011
日期:1992.1
Rhodium(II) carboxylate catalyzed C-H insertion to form a cyclopentane is shown to compete effectively with beta-hydride elimination, except when the beta-hydrogen is ternary. Cyclization of diazo ester 27 gives 28, which is converted in three steps to (+/-)-tochuinyl acetate 25. Both the cyclization to form 28 and the alkylation of 28 proceed with remarkable diastereoselectivity.