A multicomponent pathway-inspired regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles via [3+2] cycloaddition reaction

A copper catalyzed regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles using a novel three-component coupled domino reaction of aldehydes, ketones and alkyl isocyanoacetates is reported. This transformation proceeds through the formation of a chalcone followed by a [3+2] cycloaddition reaction to obtain a-cuprioisocyanide, a cyclic organocopper intermediate, which on copper-hydrogen exchange followed by oxidation exclusively offers 2,3,4-trisubstituted 1H-pyrrole.