Urea- and Thiourea-Substituted Cinchona Alkaloid Derivatives as Highly Efficient Bifunctional Organocatalysts for the Asymmetric Addition of Malonate to Nitroalkenes: Inversion of Configuration at C9 Dramatically Improves Catalyst Performance.

摘要

Inspired by the efficiency,elegance,and selectivity of enzymatic catalysis,the design of organic molecules capable of the efficient and enantioselective promotion of carbon-carbon bond-forming processes is a formidable challenge which is currently receiving considerable attention.In this context,one of the fundamental enzymatic catalyst competencies that is most difficult to engineer in synthetic systems is bifunctionality;that is,the ability of a catalyst to employ Lewis/Bronsted acidic and Lewis/Bronsted basic functionality synergistically to bring about the activation of both the nucleophilic and electrophilic components of a reaction simultaneously.