Axially Chiral Ligands and Catalysts Derived from Atropisomeric Binaphthyl Structures

The synthesis of 1,1′-bi-2-naphthol (BINOL) can be traced back to about 100 years ago, whereas the utilization of BINOL as a chiral ligand was reported by Noyori et al. in 1979. One year later in 1980, the development and application of 2,2′-bis(di-phenylphosphino)-1,1′-binaphthyl (BINAP) was reported. This milestone brings the axially chiral binaphthyl structures to the stage of asymmetric catalysis and inspires the development of a large variety of ligands and organocatalysts possessing axial chirality. This chapter traces the source of chirality, focuses on the structural diversity of the chiral catalysts and the timeline for their development, and introduces about 150 representative chiral ligands and organocatalysts derived from axially chiral binaphthyl structures, especially BINOL, 2,2′-diamino-1,1′-binaphthalene (BINAM), and 2-amino-2′-hydroxy-1,1′-binaphthyl (NOBIN). With the rapid development in the syntheses of diversified axially chiral molecules, it is expected that more novel and powerful axially chiral catalysts will be developed, and tremendous asymmetric transformations will be realized in the future.