Asymmetric Cyclization of ω-Formyl-1,3-dienes Catalyzed by a Zerovalent Nickel Complex in the Presence of Silanes
作者:Yoshihiro Sato、Nozomi Saito、Miwako Mori
DOI:10.1021/jo020438c
日期:2002.12.1
A nickel(0)-catalyzed asymmetric cyclization of omega-formyl-1,3-diene in the presence of silanes in which five- or six-membered carbocycles or pyrrolidine derivatives were afforded up to 86% ee by the use of (2R,5R)-2,5-dimethyl-1-phenylphospholane as a monodentate chiral ligand was investigated. The reaction course of this asymmetric cyclization can be explained for by two possible mechanisms: one
在硅烷存在下镍(0)催化的ω-甲酰基-1,3-二烯的不对称环化反应中,使用(2R,5元或6元碳环或吡咯烷衍生物可得到高达86%ee的硅烷研究了5R)-2,5-二甲基-1-苯基膦环烷作为单齿手性配体。这种不对称环化的反应过程可以通过两种可能的机理来解释:一种是通过环烯丙基镍中间体进行环化反应,以生产在侧链上具有内烯烃的环化产物;另一种是通过硅烷的σ键易位和氧杂环丁烷环的镍-氧键,以产生在侧链中具有末端烯烃和/或内烯烃的环化化合物。