Raney Ni efficiently catalyzes acetylene azide cycloaddition reactions to form 1,2,3-triazoles. Unlike the CuSO4/sodium ascorbate reagent system, there is no need for a reducing agent under Raney Ni catalysis. Terminal acetylene selectivity, 1,4-regioselectivity and mild reaction conditions are prominent features of the method. Mechanistic probing revealed that the reaction does not go through nickel acetylides.
