Cobalt/Salox-Catalyzed Stereoselective C−H Functionalization: Enantioselective Construction of Axially Chiral Cyclic Phosphinamides with P-Stereogenic Center

Abstract

We describe a novel cobalt/salicyloxazoline (Salox) catalytic system for enantioselective C−H functionalization, enabling the synthesis of P-stereogenic and axially chiral cyclic phosphinic amides. Chiral Salox ligands, conveniently prepared in a single step from salicylonitriles and chiral amino alcohols, facilitated this transformation with excellent enantioselectivities (92-99% ee) and moderate to good yields (31 examples, 45–89%). Mechanistic studies implicate a cobalt (III/IV/II) catalytic cycle in the C−H annulation process, providing valuable insights into the stereoselective reaction pathway.