Copper-Catalyzed Intramolecular C−N Bond Formation: A Straightforward Synthesis of Benzimidazole Derivatives in Water

A straightforward, efficient, and more sustainable copper-catalyzed method has been developed for intramolecular N-arylation providing the benzimidazole ring system. With Cu2O (5 mol %) as the catalyst, DMEDA (10 mol %) as the ligand, and K2CO3 as the base, this protocol was applied to synthesize a small library of benzimidazoles in high yields. Remarkably, the reaction was exclusively carried out in water, rendering the methodology highly valuable from both environmental and economical points of view.