I2-DMSO mediated multi-component cascade cyclization to construct pyrazolo[3,4-b]pyrrolo[3,4-d]pyridine-6-one skeleton

Abstract

A one-pot synthesis of the pyrazolo[3,4-b]pyrrolo[3,4-d]pyridin-6-one skeleton has been developed using aryl methyl ketones, 3-aminopyrazoles, and enaminamides as substrates. This method features metal-free catalysis and broad substrate compatibility (36 examples). The reaction involves the formation of two C–C and two C–N bonds, while constructing a tetrasubstituted carbon stereocenter bearing a reactive hydroxyl group.