Metal-Free C–H Functionalization and Aromatization Sequence for the Synthesis of 1‑(Indol-3-yl)carbazoles and Total Synthesis of 7‑Bromo-1-(6-bromo‑1H‑indol-3-yl)‑9H‑carbazole

An operationally simple, metal-free, cost-effective, and mild oxidative cross-coupling protocol for the synthesis of 1-indolyl tetrahydrocarbazoles to afford 1-(indol-3-yl)­carbazoles is developed. N-Chlorosuccinimide is used as a mild oxidant for the functionalization of the 1-position of tetrahydrocarbazoles, aromatization of which furnished 1-(indol-3-yl)­carbazoles in good to moderate yields without employing protection/deprotection strategy. A naturally rare dibromo 1-(indol-3-yl)­carbazole alkaloid was synthesized for the first time in two steps with an overall yield of 64% by applying the same methodology.