Rh-catalyzed aerobic oxidative cyclization of anilines, alkynes, and CO.

Transition-metal-catalyzed oxidative C-H cyclization of anilines has been an attractive and powerful strategy for the efficient construction of N-heterocycles. However, primary and tertiary anilines are rarely employed in this strategy due to the relative instability with strong oxidants or the presence of three C-N bonds. We describe here a novel Rh-catalyzed C-H cyclization of a wide range of anilines with alkynes and CO, using an aerobic oxidative protocol. Particularly, the simple primary anilines and readily prepared tertiary anilines could be easily converted to quinolin-2(1H)-ones, which are high value-added, biologically significant N-heterocycles, via C-N bond cleavage.