Microwave-assisted facile synthesis of [a]-annelated pyrazolopyrroloindoles via intramolecular azomethine imine 1,3-dipolar cycloaddition

The synthesis of [a]-annelated pyrazolopyrroloindoles via intramolecular 1,3-dipolar cycloaddition of in situ generated azomethine imine from N-allylated indole-2-carboxaldehyde, in regio- and stereoselective manner by using microwave irradiation is described. A one-pot strategy for the expedient synthesis of pyrazolopyrroloindoles has been developed. (C) 2014 Elsevier Ltd. All rights reserved.