A [3.3]Sigmatropic Rearrangement of α,β-Unsaturated Fischer Chromium Carbenes: Synthesis of Alkynol and Dienol Esters
摘要:
A novel [3.3]sigmatropic rearrangement of in situ formed alpha,beta-unsaturated Fischer acyloxy carbenes forming alkynol esters is described. For example, reaction of tetramethylammonium pentacarbonyl(1-oxo-2-butenyl)chromate(1-) (4) with 4-methoxybenzoyl chloride gave 2-methyl-3-butyn-2-yl 4-methoxybenzoate (8) in 32% yield. In addition to the rearrangement products, dienol esters formed by a formal beta-hydride elimination-reductive elimination sequence were usually isolated. In the above example, 3-methylbuta-1,3-dien-1-yl 4-methoxybenzoate (9) was obtained (16%) as the side product. (C) 2000 Elsevier Science Ltd. All rights reserved.
presence of the N-heterocyclic carbene gold catalyst (NHC-AuIPr, 7), propargyl esters 1a–f and 13 undergo a [4C+3C] cycloaddition reaction with cyclopentadiene and furan under mild conditions. The evidence suggests that the formation of the seven-membered ring occurs by a direct cycloaddition process, rather than a stepwise cyclopropanation/Cope rearrangement sequence.
The mechanism of the catalysis of the reversible (propargyl ester)/(allenyl ester) rearrangement (10 ⇄ 11) by silver(I) ions was investigated, using optically active and diastereoisomeric esters as well as 14C- and 18O-labelling.
The Preparation of t-Acetylenic Carbinol Esters and Related Compounds<sup>1</sup>
作者:G. F. Hennion、S. Olivia Barrett
DOI:10.1021/ja01566a032
日期:1957.5
Preparation of allenyl esters
作者:David G. Oelberg、Melvyn D. Schiavelli
DOI:10.1021/jo00430a031
日期:1977.5
A [3.3]Sigmatropic Rearrangement of α,β-Unsaturated Fischer Chromium Carbenes: Synthesis of Alkynol and Dienol Esters
作者:Björn C. Söderberg、Shannon N. O'Neil、Angela C. Chisnell、Jian Liu
DOI:10.1016/s0040-4020(00)00216-7
日期:2000.7
A novel [3.3]sigmatropic rearrangement of in situ formed alpha,beta-unsaturated Fischer acyloxy carbenes forming alkynol esters is described. For example, reaction of tetramethylammonium pentacarbonyl(1-oxo-2-butenyl)chromate(1-) (4) with 4-methoxybenzoyl chloride gave 2-methyl-3-butyn-2-yl 4-methoxybenzoate (8) in 32% yield. In addition to the rearrangement products, dienol esters formed by a formal beta-hydride elimination-reductive elimination sequence were usually isolated. In the above example, 3-methylbuta-1,3-dien-1-yl 4-methoxybenzoate (9) was obtained (16%) as the side product. (C) 2000 Elsevier Science Ltd. All rights reserved.