Aromatic hydroxyl group-a hydrogen bonding activator in bifunctional asymmetric organocatalysis

Recent progress in asymmetric catalysis has contributed to the development of a diverse range of chiral organocatalysts that differ in their origin, structure and mode of activation. The bifunctional organocatalysts bearing aromatic hydroxyl (or phenolic) groups have emerged as a privileged class of organocatalyst. In these bifunctional organocatalysts, the aromatic hydroxyl group functions as a weak Bronsted acid or hydrogen bonding site and a nucleophilic or basic moiety such as amine and phosphine serve as a base or hydrogen bond acceptor. The bifunctional organocatalysts having these moieties have not been reviewed. In this review we are presenting the asymmetric transformations catalyzed by the bifunctional organocatalyst bearing an aromatic hydroxyl group.