An Expedient Lewis-Acid-Catalyzed Microwave-Assisted Domino Approach to Coumarin-Fused Pyrroles and Related Heterocycles under Neat Conditions

Abstract

A superior Lewis acid-catalyzed and microwave-assisted, facile, solvent-free, one-pot quick access to a novel class of a set of diversely substituted coumarin, dimedone and naphthoquinone-fused pyrroles via an annulation reaction between different kinds of carbo-and heterocyclic enaminones and a group of α-aroyl/heteroaryl/acetylidene malonates, 3-aroylidene-2-oxindoles is reported. This LUMO-lowering technique involving a powerful Lewis acid relies on the installation of pyrrole rings good to high chemical yields with a wide scope of diversely substituted substances. Furthermore, a direct C(sp3)-H hydroxylation of 3-pyrrolocoumarinyl-2-oxindoles to therapeutically exciting 3-hydroxy-3-pyrrolocoumarinyl-2-oxindoles bearing a tetra-substituted chiral carbon center in high yields was achieved under metal-free conditions. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim