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Enantioselective Synthesis of Functionalized Nitrocyclopropanes by Organocatalytic Conjugate Addition of Bromonitroalkanes to α,β‐Unsaturated Enones
Author(s) -
Lv Jian,
Zhang Jiaming,
Lin Zhu,
Wang Yongmei
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801651
Subject(s) - enantioselective synthesis , conjugate , reagent , kinetic resolution , enone , catalysis , chemistry , selectivity , organic chemistry , organocatalysis , michael reaction , combinatorial chemistry , mathematics , mathematical analysis
A general enantioselective synthesis of functionalized nitrocyclopropanes by organocatalytic conjugate addition of a variety of bromonitroalkanes to α,β‐unsaturated enone systems is presented. The process, efficiently catalyzed by the salts of 9‐amino‐9‐deoxyepiquinine 1 d serves as a powerful approach to the preparation of synthetically and biologically important cyclopropanes with high levels of enantio‐ and diastereoselectivities. Since only 0.6 equivalents of bromonitromethane are used as a reagent, ( S )‐ 2 e is obtained enantiomerically pure by employing chiral 1 d as a highly efficient catalyst for its kinetic resolution (97 % ee at 51 % conversion, selectivity s =120).