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.