Palladium-Catalyzed Synthesis of 2,3-Diaryl- N-methylindoles from ortho-Alkynylanilines and Aryl Pinacol Boronic Esters.

A palladium-catalyzed synthesis of 2,3-diaryl- N-methylindoles from o-alkynylanilines and aryl pinacol boronic esters was developed. The system possesses high functional group tolerance and a broad substrate scope with a variety of aryl pinacol boronic esters to provide valuable 2,3-diaryl- N-methylindoles in moderate to good yields. Remarkably, the sequential reaction controlled by iridium-catalyzed C-H borylation or palladium-catalyzed alkynylation followed by the present palladium-catalyzed C3 arylation reaction provided functionalized 2,3-diaryl- N-methylindoles in good yields.