Rhodium‐Catalyzed P III ‐Directed ortho ‐C−H Borylation of Arylphosphines

Transition‐metal‐mediated metalation of an aromatic C−H bond that is adjacent to a tertiary phosphine group in arylphosphines via a four‐membered chelate ring was first discovered in 1968. Herein, we overcome a long‐standing problem with the ortho ‐C−H activation of arylphosphines in a catalytic fashion. In particular, we developed a rhodium‐catalyzed ortho ‐selective C−H borylation of various commercially available arylphosphines with B 2 pin 2 through P III ‐chelation‐assisted C−H activation. This discovery is suggestive of a generic platform that could enable the late‐stage modification of readily accessible arylphosphines.