Enantioselective cyclopropanation of (Z)-3-substituted-2-(4-pyridyl)-acrylonitriles catalyzed by Cinchona ammonium salts?

Organic & Biomolecular Chemistry Pub Date: 2016-02-17 DOI: 10.1039/C6OB00154H

Abstract

Cyclopropane esters holding two quaternary centres were prepared in high yields, complete diastereoselection and up to 83% ee. The reaction described herein entailed reacting (Z)-3-substituted-2-(4-pyridyl)-acrylonitrile, a reactive class of Michael acceptor, with 2-bromomalonate esters in the presence of Cinchona derived phase-transfer catalysts. The reaction allowed multi-gram preparation of the desired products.

Graphical abstract: Enantioselective cyclopropanation of (Z)-3-substituted-2-(4-pyridyl)-acrylonitriles catalyzed by Cinchona ammonium salts
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