Divergent syntheses of fused β-naphthol and indene scaffolds by rhodium-catalyzed direct and decarbonylative alkyne-benzocyclobutenone couplings.

A tunable rhodium-catalyzed intramolecular alkyne insertion reaction proceeding through the CC cleavage of benzocyclobutenones is described. Selective formation of either the direct or decarbonylative insertion product can be controlled by using different catalytic systems. A variety of fused β-naphthol and indene scaffolds were obtained in good yields with high functional group tolerance. This work illustrates a divergent approach to synthesize fused-ring systems by CC activation/functionalization.