Intramolecular Arene C–H to C–P Functionalization Mediated by Nickel(II) and Palladium(II)

A tris­(phosphine) ligand with a triarylbenzene backbone was employed to support mono-nickel­(II) and -palladium­(II) complexes. Two phosphine arms coordinated to the metal center, while the third phosphine was found to form a C–P bond with dearomatization of the central arene. Deprotonation effected the rearomatization of the central ring and metal reduction from M­(II) to M(0). The overall conversion corresponds to a functionalization of an unactivated arene C–H bond to a C–P bond. This transformation represents a rare type of mechanism of C–H functionalization, facilitated by the interactions of the group 10 metal with the arene π system. This conversion is reminiscent of and expands the scope of recently reported intramolecular rearrangements of biaryl phosphine ligands common in group 10 catalysis.