Cp*Co(III)-Catalyzed Regioselective Synthesis of Cyclopenta[ b]carbazoles via Dual C(sp2)-H Functionalization of 1-(Pyridin-2-yl)-indoles with Diynes.

Cp*Co(III)-catalyzed synthesis of cyclopenta[ b]carbazoles from 1-(pyridin-2-yl)-indoles and diynes is developed. This reaction involves dual C-H activation of indoles and domino cyclizations with diynes and has excellent regioselectivity, high efficiency, a broad substrate scope, and tolerance for various functional groups. A series of cyclopenta[ b]carbazole molecular scaffolds are obtained in good to excellent yields.