Rhodium(III)-Catalyzed Direct Selective C(5)–H Oxidative Annulations of 2‑Substituted Imidazoles and Alkynes by Double C–H Activation

Double C–H activations of C(5)–H and Csp²–H of 2-substituted <i>N</i>-vinyl- or arylimidazoles were realized without heteroatom-directing assistance by rhodium(III) catalyst. A subsequent oxidative annulation reaction with alkynes efficiently produced aza-fused heterocycles with high molecular complexity in low to excellent yields