General Approach To Construct Azepino[2,3‑b:4,5‑b′]diindoles, Azocino[2,3‑b:4,5‑b′]diindoles, and Azonino[2,3‑b:4,5‑b′]diindoles via Rh(II)-Catalyzed Reactions of 3‑Diazoindolin-2-imines with 3‑(Bromoalkyl)indoles

Rh­(II)-catalyzed reactions of 3-diazoindolin-2-imines with 3-(2-bromoethyl)­indoles, 3-(3-bromopropyl)­indoles, and 3-(4-bromobutyl)­indoles, followed by treatment with 1,8-diazabicyclo[5.4.0]­undec-7-ene (DBU) in a one-pot operation furnished azepino­[2,3-b:4,5-b′]­diindoles, azocino­[2,3-b:4,5-b′]­diindoles, and azonino­[2,3-b:4,5-b′]­diindoles, respectively. Structural uniqueness of the products, broad substrate scope, mild reaction conditions, and readily available starting materials are the merits of this approach.