Copper-Catalyzed Cross-Couplings of Organometallic Reagents with and without Assistance from PN Ligands

In this article, recent developments of copper-catalyzed cross-couplings are discussed. Critical results that demonstrate the effectiveness of copper catalysts, ligated by P,N-ligands, for cross-coupling reactions are presented to showcase the potential emergence of copper as an alternative to palladium. The observation that the reaction of heteroaryl coupling partners also proceeds under 'ligand-free' conditions holds great promise for developing copper catalysis as a complementary system to palladium catalysis in areas in which palladium either performs unsatisfactorily or requires custom-designed ligands. 1 Introduction 2 Rationale for the Use of Hybrid Bidentate Ligands 3 Coupling with Organosilicon Reagents 4 Coupling with Organoboron Reagents 5 Coupling with Organoindium Reagents 6 General Catalytic Cycle 7 Conclusion and Perspectives.