Preparation of Imines by Oxidative Coupling of Benzyl Alcohols with Amines Catalysed by Dicopper Complexes

Complexation of 2,7‐bis(2‐pyridyl)‐1,8‐naphthyridine (bpnp) with Cu2O in formic acid under aerobic conditions provided a dicopper complex [Cu2(bpnp)(μ‐OH)(HCOO)3] (1). This complex has been characterized by X‐ray crystallographic and spectroscopic analysis. With O2 as the oxidant, complex 1 is an efficient catalyst for the oxidative coupling of alcohols with amines or diamines, leading to the corresponding imines or diimines in good to excellent yields. A dicopper complex has been found to be an efficient catalyst for the oxidative coupling of benzyl alcohols with amines or diamines, leading to the corresponding imines or diimines in good to excellent yields without using any organic solvent.