Rhodium-Catalyzed Silylcarbocyclization (SiCaC) and Carbonylative Silylcarbocyclization (CO-SiCaC) Reactions of Enynes

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• 作者：Iwao Ojima ; An T. Vu ; Seung-Yub Lee ; James V. McCullagh ; Andrew C. Moralee ; Masaki Fujiwara ; and Tram H. Hoang
• 刊名：Journal of the American Chemical Society
• 出版年：2002
• 出版时间：August 7, 2002
• 年：2002
• 卷：124
• 期：31
• 页码：9164 - 9174
• 全文大小：160K
• 年卷期：v.124,no.31(August 7, 2002)
• ISSN：1520-5126

文摘

The reaction of a 1,6-enyne with a hydrosilane catalyzed by Rh(acac)(CO)₂, Rh₄(CO)₁₂, or Rh₂Co₂(CO)₁₂ under ambient CO atmosphere or N₂ gives 2-methyl-1-silylmethylidene-2-cyclopentane or itsheteroatom congener in excellent yield through silylcarbocycization (SiCaC) process. The same reaction,but in the presence of a phosphite such as P(OEt)₃ and P(OPh)₃ under 20 atm of CO, affords thecorresponding 2-formylmethyl-1-silylmethylidene-2-cyclopentane or its heteroatom congener with excellentselectivity through carbonylative silylcarbocycization (CO-SiCaC) process. The SiCaC reaction has alsobeen applied to a 1,6-enyne bearing a cyclohexenyl group as the alkene moiety and a 1,7-enyne system.The functionalized five- and six-membered ring systems obtained by these novel cyclization reactions serveas useful and versatile intermediates for the syntheses of natural and unnatural heterocyclic and carbocycliccompounds. Possible mechanisms for the SiCaC and CO-SiCaC reactions as well as unique features ofthese processes are discussed.