Construction of Adjacent Quaternary and Tertiary Stereocenters by Conjugate Addition Using Polymer-Supported Cinchona Alkaloids as Catalysts

Abstract

A series of polymer-bound cinchona alkaloids has been prepared. The resultant polymer-bound cinchona alkaloids have been used as the catalysts for the asymmetric Michael reaction of 1,3-dicarbonyl compounds and N-benzylmaleimide. The corresponding asymmetric Michael addition product, the first example of adjacent quaternary and tertiary stereocenters synthesized in the presence of a polymer-bound catalyst, has a selectivity of up to 86% ee. Besides, immobilized alkaloid V retains stereochemical reactivity even after being recycled for six times. A series of polymer-bound cinchona alkaloids has been prepared. The resultant polymer-bound cinchona alkaloids have been used as the catalysts for the asymmetric Michael reaction of 1,3-dicarbonyl compounds and N-benzylmaleimide. The corresponding asymmetric Michael addition product, the first example of adjacent quaternary and tertiary stereocenters synthesized in the presence of a polymer-bound catalyst, has a selectivity of up to 86% ee. Besides, immobilized alkaloid V retains stereochemical reactivity even after being recycled for six times.