Accessing Polycyclic Heteroarenes Enabled by Copper-Catalyzed Aerobic Oxidative C-H/C-H [4 + 2] Annulation of 3-Arylindole Derivatives.

Several polycyclic aromatic hydrocarbons are delivered at room temperature by copper-catalyzed aerobic oxidative C-H/C-H [4 + 2] annulation of alkyl-substituted 3-arylindole derivatives. Specifically, dual aryl C-H functionalization is furnished under mild conditions through the 1,2-migration of copper catalyst and regioselective alkyne insertion. Mechanistic experiments demonstrate that the C-H bond cleavage on the indole and phenyl rings is not involved in the rate-limiting step.