Enantioselective synthesis of functionalized nitrocyclopropanes by organocatalytic conjugate addition of bromonitroalkanes to alpha,beta-unsaturated enones.
A general enantioselective synthesis of functionalized nitrocyclopropanes by organocatalytic conjugate addition of a variety of bromonitroalkanes to alpha,beta-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).
Lv
Jian
J
Department of Chemistry, Key Laboratory of Elemento-Organic Chemistry, Nankai University, 97 Weijin Road, Tianjin, China.
Zhang
Jiaming
J
Lin
Zhu
Z
Wang
Yongmei
Y
D000473:Alkanes / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D003521:Cyclopropanes / Q000138:chemical synthesis / Q000737:chemistry*; D007700:Kinetics; D013237:Stereoisomerism
D000473:Alkanes; D003521:Cyclopropanes