Palladium-Catalyzed Electro-oxidative C–H Amination toward the Synthesis of Pyrido[1,2-a]benzimidazoles with Hydrogen Evolution

Transition-metal-catalyzed oxidative C–H/N–H coupling reaction is an important method to construct C–N bonds. However, stoichiometric oxidants were usually necessary. Here, we report a palladium-catalyzed electro-oxidative intramolecular C–H/N-H annulation reaction without an external oxidant or additive. A variety of pyrido[1,2-a]benzimidazoles were constructed by a simple, green, and mild path. Experimental results suggested that Pd(0) could be oxidized on the anode to be recycled.