Chiral Phosphine-Phosphoramidite Ligands for Highly Efficient Ir-Catalyzed Asymmetric Hydrogenation of Sterically Hindered N-Arylimines

A mild and general iridium-catalyzed, highly enantioselective hydrogenation of sterically hindered N-arylimines with a new H-8-BINOL-derived phosphine-phosphoramidite ligand has been developed. The present catalytic system features high turnover numbers (up to 100000) and good to perfect enantioselectivities (up to 99% ee) for the hydrogenation of a variety of sterically hindered N-arylimines.