Cupric oxide nanowires on three-dimensional copper foam for application in click reaction

Readily prepared CuO nanowires (CuO NWs) have been found to be effective heterogeneous catalysts for the 1,3-dipolar cycloaddition (CuAAC) reaction without using any additional support and bases. Examination of CuO nanowire catalysts synthesized at various temperatures showed that the use of CuO-600 catalyst was the best choice for the success of the present click reaction. Not only aromatic and heteroaromatic alkynes but also alkylalkynes were catalyzed regioselectively, affording triazoles in excellent yields. Furthermore, we have identified that the reaction proceeded in a heterogeneous manner. It is noteworthy that the CuO-600 catalyst can be easily recovered and reused nine times.