Flash Communication: Visible-Light-Driven, Cobalt-Mediated Selective C–H Arylation of 2,2′-Bipyridine

Abstract Herein, we report a visible-light-driven, cobalt-mediated, highly selective C–H arylation method to afford aryl-2,2′-bipyridine, a widely used class of ancillary ligands in transition metal catalysis. This arylation reaction exhibits good-to-excellent C6 selectivity for a variety of aryl groups, allowing for isolation of the 6-isomer in its pure form. Mechanistic studies provided evidence for the generation of an aryl radical by the joint action of [Co(bpy)3] species and visible light, enabling arylation under mild conditions. Compared to previous work, this method employs cost-effective reagents and provides one-step, direct access from 2,2′-bipyridine to a broad range of electronically varied 6-aryl-2,2′-bipyridine products.