文摘
Factors leading to the formation of a hexahydroaporphine-like cyclizing side product were studied systematically for the first time and the ratio of this side product was controlled effectively. To understand better the electronic effect of substrates on the formation of side products, different 1-benzyloctahydroisoquinolines with substituted groups on nitrogen or benzene ring were compared. A plausible mechanism of cyclizing reaction was proposed, and key intermediates as well as transition states were analyzed using DFT calculations.