Efficient Catalytic Oxidative Dehydrogenation of Tetrahydroisoquinolines Via Copper Catalysis

An efficient copper-catalyzed oxidative dehydrogenation of tetrahydroisoquinolines has been developed, giving a general and convenient strategy from amines toward imines in excellent yields. A series of tetrahydroisoquinolines bearing electron-donating/withdrawing groups proceeded smoothly with air (O-2) as oxidant. The oxidative dehydrogenation proved to be an atom-economical and environmentally friendly strategy, which could effectively avoid generating stoichiometric hazardous wastes. In addition, this methodology provides a convenient and effective approach to the reutilization of amines, especially for the synthesis of enantiomerically pure substances, such as (+)-Solifenacin, in industrial process. Preliminary experimental results revealed that the reaction was carried out via a process of oxidative dehydrogenation.