One-Pot Access to Benzo[a]carbazoles via Palladium(II)-Catalyzed Hetero- and Carboannulations

A Pd­(II)-catalyzed direct synthesis of benzo­[a]­carbazoles has been achieved through amino­palladation of alkynes, followed by intramolecular nucleophilic addition of the generated carbon–palladium bond to a tethered cyano/aldehyde group. Compared to literature procedures, this synthetic approach is operationally simple, uses simple substrates, and offers a fast intramolecular assembly resulting in the direct synthesis of benzo­[a]­carbazoles in which a wide variation of substituents at different sites is well-tolerated, leaving enough opportunity for diversification.