Asymmetric Approach toward Chiral Cyclohex-2-enones from Anisoles via an Enantioselective Isomerization by a New Chiral Diamine Catalyst
作者:Jung Hwa Lee、Li Deng
DOI:10.1021/ja308623n
日期:2012.11.7
A 3-step asymmetricapproach toward the optically active chiral cyclohex-2-enones from anisoles has been developed. The crucial asymmetric induction step is an unprecedented catalytic enantioselective isomerization of β,γ-unsaturated cyclohex-3-en-1-ones to the corresponding α,β-unsaturated chiral enones. This new asymmetric transformation was realized by cooperative iminium-base catalysis with an
Alkinyl terminating groups in biogenetic-like cyclizations to steroids
申请人:The Board of Trustees of Leland Stanford Junior University
公开号:US04055603A1
公开(公告)日:1977-10-25
Polyenine compounds are provided having the naturally occurring geometry and a group which in the presence of acid initiates a carbocation cyclization to a steroid or A-nor-steroid structure, particularly the pregnane parent structure. The compounds are formed for the most part by condensation of two units prepared from readily available small molecules and are joined to form a polyenine, usully having a substituted carbocyclic ring which upon contact with a Lewis acid catalyst (includes protonic) cyclizes directly to provide the 5-membered D ring as well as substitution at the C-20 position.