A mild dihydrobenzooxaphosphole oxazoline/iridium catalytic system for asymmetric hydrogenation of unfunctionalized dialins

Abstract

Air-stable P-chiral dihydrobenzooxaphosphole oxazoline ligands were designed and synthesized. When they were used in the iridium-catalyzed asymmetric hydrogenation of unfunctionalized 1-aryl-3,4-dihydronaphthalenes under one atmosphere pressure of H2, up to 99:1 e.r. was obtained. High enantioselectivities were also observed in the reduction of the exocyclic imine derivatives of 1-tetralones.