Two‐Pot Synthesis of Indolizinoindole Derivatives via Lewis Acid‐Mediated Intramolecular Regioselective Cyclization of 3‐Acylpyrroles

Abstract

A two‐pot method has been developed to access indolizino[8,7‐b]indole derivatives through Lewis acid‐mediated regioselective C5‐cyclization of 3‐acylpyrrole prepared from the feedstock materials. The overall reaction proceeds through amine‐catalyzed direct aldol reaction/Paal‐Knorr reaction/oxidation between succinaldehyde, aromatic aldehyde, and tryptamine in a sequential multicomponent fashion for N‐alkyl pyrrole followed by dearomative cyclization. A series of substituted indolizino[8,7‐b]indoles have been prepared with good yields and excellent regioselectivity.