Development of Axially Chiral Dicarboxylic Acid Catalyzed Asymmetric Transformations

In the past decade, chiral Bronsted acid catalysis has become a leading tool to achieve catalytic asymmetric transformations. As a source of Bronsted acids, poorly acidic hydrogen bonding donors like (thio) ureas and alcohols had been used in the early study, and strongly acidic phosphoric acids then emerged as an indispensable option. We became interested in the use of chiral carboxylic acids, as they have a distinct acidity which cannot be provided by other Bronsted acids. To this end, we developed axially chiral dicarboxylic acids bearing two carboxylic acids at the 2,2'-positions of a binaphthyl unit, and succeeded in applying these catalysts to a variety of asymmetric transformations.