Abstract
? 2021 Elsevier LtdA palladium-catalyzed synthesis of indole fused α-carbolines (pyridodiindoles) from 2,3′-biindoles and nitriles has been developed. This conversion involves the double C–H activation and cyclization of 2,3′-biindoles with nitriles via C–C and C–N bond formation in a single step. However, C-3 cyanated biindoles were formed through a retro-Mannich pathway when the reaction was carried out with ethyl cyanoacetate.