Hetero [4 + 2] Cycloadditions of (Trialkylsilyl)vinylketenes. Synthesis of α,β-Unsaturated δ-Valerolactones and -Lactams
作者:Dawn M. Bennett、Iwao Okamoto、Rick L. Danheiser
DOI:10.1021/ol9907217
日期:1999.8.1
[formula: see text] HeteroDiels-Alderreactions of (trialkylsilyl)vinylketenes (TAS-vinylketenes) with carbonyl and imino dienophiles are described. TAS-vinylketenes participate as electron-rich dienes in [4 + 2] cycloadditions with diethyl ketomalonate to afford alpha,beta-unsaturated delta-valerolactones in good yield. Nonenolizable N-alkyl- and N-(trimethylsilyl)imines combine with TAS-vinylketenes
Synthesis of Highly Substituted Cyclopentenones via the [4 + 1] Cycloaddition of Nucleophilic Carbenes and Vinyl Ketenes
作者:James H. Rigby、Zhengqiang Wang
DOI:10.1021/ol0272141
日期:2003.2.1
[reaction: see text] Vinylketenes have been shown to undergo [4 + 1] cycloaddition with a variety of nucleophilic carbenes to deliver highly substituted cyclopentenones as products.
Reactions of (Trialkylsilyl)vinylketenes with Lithium Ynolates: A New Benzannulation Strategy
作者:Wesley F. Austin、Yongjun Zhang、Rick L. Danheiser
DOI:10.1021/ol051307b
日期:2005.9.1
(Trialkylsilyl)vinylketenes react with lithium ynolates to produce highly substituted phenols in a new benzannulation strategy that proceeds via the 6 pi electrocyclization of an intermediate 3-(oxido)dienylketene.
Stereoselective Synthesis of Highly Substituted Cyclopentenones through [4+1] Annulations of Trialkylsilyl Vinyl Ketenes with α-Benzotriazolyl Organolithium Compounds
作者:Christopher P. Davie、Rick L. Danheiser
DOI:10.1002/anie.200501579
日期:2005.9.12
(Trialkylsilyl)vinylketenes: Synthesis and Application as Diene Components in Diels−Alder Cycloadditions
作者:Jennifer L. Loebach、Dawn M. Bennett、Rick L. Danheiser
DOI:10.1021/jo981289u
日期:1998.11.1
New strategies for the synthesis of (trialkylsilyl)vinylketenes ("TAS-vinylketenes") are described based on the photochemical Wolff rearrangement of alpha-silyl-alpha'-diazo-alpha,beta-unsaturated ketones and the 4 pi electrocyclic ring opening of cyclobutenones. These remarkably robust vinylketenes undergo highly regioselective [4 + 2] cycloadditions with reactive olefinic and acetylenic dienophiles to produce highly substituted cyclohexenones and phenols in which the ketene carbonyl dominates in controlling the regiochemical course of the reaction. The stereochemical course of these cycloadditions follows the Alder endo rule, as illustrated in the reaction of nitropropene with TBS-vinylketene 22.