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 N-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.
Rhodium(iii)-catalyzed vinylic sp2 C-H bond functionalization: Efficient synthesis of pyrido[1,2-α]benzimidazoles and imidazo[1,2-α]pyridines
A simple approach for synthesis of novel aza-fused scaffolds such as pyrido[1,2-α]benzimidazoles and imidazo[1,2-α]pyridines was developed by Rh(iii)-catalyzed direct oxidative coupling between alkenes and unactivated alkynes without an extra directing group. The method would allow a broad substrate scope, providing fused heterocycles with potential biological properties. The Royal Society of Chemistry.