Gold nanoclusters stabilized by a hydrophilic polymer, poly(N-vinyl-2-pyrrolidone), (Au:PVP) catalyze two contradictory types of the reaction from N-benzyl secondary amines with unactivated alkenes in EtOH under basic conditions. One is an intramolecular addition reaction that also starts from N-sulfonylamine or primary amine as previously reported. The other involves the oxygenative cleavage of alkene, giving the corresponding gamma-lactam compound.