A Redox Transmetalation Step in Nickel-Catalyzed C–C Coupling Reactions

[Image: see text] Ni-catalyzed C–H functionalization reactions are becoming efficient routes to access a variety of functionalized arenes, yet the mechanisms of these catalytic C–C coupling reactions are not well understood. Here, we report the catalytic and stoichiometric arylation reactions of a nickel(II) metallacycle. Treatment of this species with silver(I)–aryl complexes results in facile arylation, consistent with a redox transmetalation step. Additionally, treatment with electrophilic coupling partners generates C–C and C–S bonds. We anticipate that this redox transmetalation step may be relevant to other coupling reactions that employ silver salts as additives.