A new general synthetic route towards benzylisoquinoline alkaloids was developed. The key step of this route is Cu-catalyzed cascade oxidation-aromatization of 1-benzyl-3,4-dihydroisoquinolines. The three benzylisoquinoline alkaloids such as neolitacumonine, mollinedine and papaverine were synthesized starting from piperonaldehyde and 3,4-dimethoxybenzaldehyde by 8 steps in 42%, 37% and 37% overall yields, respectively.