Research Progress in Ligand-Assisted Copper-Catalyzed C-N Cross-Coupling Reaction in Aqueous Media or Pure Water

Copper-catalyzed Ullmann-type C-N coupling reaction is one of the most effective methods to construct the C-N bonds.Water, as green and clean solvent, has been successfully employed in various organic reactions.According to the structure of ligands, the progress of ligand-assisted copper-catalyzed C-N cross-coupling reaction in aqueous media or pure water is summarized comprehensively, and the ligands include diamines, hydrazides, phenanthrolines, carbohydrates, pyridine-N-oxides, quinolines, oximes and salen.In addition, ligand-free copper-catalyzed C-N coupling reactions in aquous media or pure water are also reviewed.