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Highly Enantioselective Construction of Strained Spiro[2,3]hexanes through a Michael Addition/Ring Expansion/Cyclization Cascade
Author(s) -
Zhao ChuanGang,
Feng ZhiTao,
Xu GuoQiang,
Gao Ang,
Chen JingWei,
Wang ZhuYin,
Xu PengFei
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201912834
Subject(s) - enantioselective synthesis , chemistry , enamine , ring (chemistry) , reactivity (psychology) , michael reaction , nucleophile , amine gas treating , organocatalysis , hexane , catalysis , organic chemistry , medicinal chemistry , stereochemistry , combinatorial chemistry , medicine , alternative medicine , pathology
We herein report a general organocatalytic enantioselective strategy for the construction of highly strained spiro[2,3]hexane skeletons from methylenecyclopropanes and a broad selection of α,β‐unsaturated aldehydes. The reaction proceeds through a Michael addition followed by ring expansion of methylenecyclopropanes and nucleophilic attack of an enamine to realize the construction of spiro[2,3]hexanes. Key to the success of this approach are the utilization of an electron‐deficient difluoro‐substituted secondary amine catalyst and the intrinsic reactivity of methylenecyclopropanes.