Asymmetric Organocatalytic Cascade Reactions Catalyzed by Chiral Bronsted Acids

In recent years, asymmetric organocatalytic cascade reactions have emerged as a powerful and environmentally friendly tool for the rapid assembly of complex chiral molecules from simple and readily available starting materials in a single process, and have attracted much attention as the advantages of both cascade reactions and organocatalysis are merged. In this context, asymmetric organocatalytic cascade reactions catalyzed by the chiral amines are the most intensively studied as they are capable of activating the carbonyl compounds through enamine catalysis and iminium catalysis. Recently, chiral Bronsted acid catalysis has gained continuously increasing interest in the area of organocatalysis. With the development of asymmetric Bronsted acid catalysis, chiral Bronsted acid-catalyzed asymmetric cascade reactions have made considerable advancement. In this review, key development of asymmetric organocatalytic cascade reactions catalyzed by chiral Bronsted acids is summarized.