Cu+-based composite metal oxides enable the efficient [4+2] annulation reactions between tertiary anilines and tetrahydrofuran

An efficient heterogeneous catalytic system for the [4 + 2] annulation reactions between tertiary anilines and tetrahydrofuran has been developed based on CuCoFe layered double oxide in the study. Cu + species was believed to play the crucial role in the catalytic transformation, and synergistic effect between Cu and CoFe species was observed in the reaction. Various tertiary anilines could be tolerated by the present catalytic system. A series of control experiments were conducted to determine the reaction intermediates. A distinctive reaction mechanism has been described for the annulation reaction based on these results and kinetic isotopic effects experiments.