Efficient Catalytic Oxidative Dehydrogenation of Tetrahydroisoquinolines via Copper Catalysis

Abstract

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 (O2) 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.