P,N Ligand in Ni-Catalyzed Cross-Coupling Reactions: A Promising Tool for π-Functionalization

Bidentate P,N ligands, integrating phosphine and nitrogen donors, are highlighted for their versatile characteristics, offering both electronic and steric tunability. Their hemilabile nature, coupled with the ability to modulate both electronic and steric properties through the choice of donor atoms and substituents, has expanded the horizons of chemical transformations. This Review focuses on Ni-catalyzed cross-coupling reactions mediated by P,N ligands. The asymmetrical nature of P,N ligands, with each donor atom playing a specific role in the catalytic cycle, offers control, stability, and unique regioselectivity in catalytic processes. In particular, the Ni/P,N-catalytic system exhibits remarkable reactivity with pi-substrates including alkenes, alkynes, and allenes. A thorough mechanistic understanding of these processes offers insights into the trends and future directions in Ni/P,N-catalyzed cross-coupling reactions.