Abstract
Cinchona alkaloid derivatives have emerged as one of the most powerful classes of chiral catalysts in asymmetric synthesis. At a fundamental level, this development resulted from the key mechanistic discovery that modified cinchona alkaloids could serve as efficient and general base catalysts to promote highly enantioselective asymmetric reactions via the activation of a broad range of nucleophiles. Moreover, this mode of asymmetric catalysis has been successfully coupled with various modes of catalysis centered on the activation of electrophiles, such as acid and iminium catalysis, thereby leading to the development of highly efficient and general cooperative catalysis based on organic catalysts. Importantly, this powerful strategy, proven to be among the most generally applicable in asymmetric catalysis, has been extended to multifunctional catalysis, which promotes and controls multiple stereoselective steps involving distinct transition states. In this review, we highlight the practice of these newly emerged concepts as a widely applicable strategy for the development of an extremely broad range of stereoselective transformations.