Asymmetric Michael Addition Reactions between 3‐Substituted Benzofuran‐2(3<i>H</i>)‐ones and 1,1‐Bis(phenylsulfonyl)ethylene Catalyzed by Bifunctional Catalysts Containing Tertiary Amine and Thiourea Groups

Abstract

Abstract Highly enantioselective catalytic conjugate additions of 3‐substituted benzofuran‐2(3 H )‐ones to 1,1‐bis(phenylsulfonyl)ethylene in the presence of catalysts based on Cinchona alkaloids and containing tertiary amine and thiourea groups have been developed. Good to excellent stereoselectivities (up to 99 % ee ) could be achieved. An interesting effect of substituent positions on stereoselectivities was observed, and a theoretical study to explain this phenomenon was undertaken.