Rhodium-Catalyzed Annulative Coupling Using Vinylene Carbonate as an Oxidizing Acetylene Surrogate

Transition-metal-catalyzed C–H activation and subsequent oxidative cyclization with alkynes has been a powerful tool for the synthesis of polycyclic aromatic compounds. Despite the substantial progress in this field, it is still a significant challenge to establish synthetic methodologies for the construction of nonsubstituted vinylene-fused aromatics. We herein report a Rh(III)-catalyzed C–H/N–H annulation with vinylene carbonate as an acetylene surrogate. Vinylene carbonate also acts as an internal oxidant to regenerate the Rh(III) species in situ; thus, no external oxidant is required to trigger the oxidative annulation. This protocol is applicable to the direct synthesis of various N-heteroaromatics.