Direct Synthesis of Quinolines via Co(III)-Catalyzed and DMSO-Involved C-H Activation/Cyclization of Anilines with Alkynes.

A unique Co(III)-catalyzed and DMSO-involved C-H activation/cyclization of simple, cheap, and easily available anilines with alkynes for direct and highly efficient synthesis of privileged quinolines with exclusive regioselectivity and broad substrate/functional group tolerance and in good to excellent yields, where DMSO was employed as both the solvent and the C building block of quinoline products, is reported. Mechanistic experiments revealed that the versatile reaction might employ the 2-vinylbenzenamine species as the active intermediate.