Cobalt/Salox-Catalyzed Enantioselective C-H Functionalization of Arylphosphinamides.

Abstract

Previous methods on CoIII -catalyzed asymmetric C-H activation rely on the use of tailor-made cyclopentadienyl-ligated CoIII complexes, which require lengthy steps for the preparation. Herein, we report an unprecedented enantioselective C-H functionalization enabled by a simple cobalt/salicyloxazoline (Salox) catalysis. The chiral Salox ligands can be easily prepared in one step from salicylonitrile and chiral amino alcohols. A broad range of P-stereogenic compounds were synthesized in high yields with excellent enantioselectivities (45 examples, up to 99 % yield and >99 % ee). The isolation and characterization of several intermediates provided insights into the generation of active catalytic cobalt species, the action of Salox, and the mode of stereocontrol.