Generation of sulfonated 1-isoindolinones through a multicomponent reaction with the insertion of sulfur dioxide

Abstract

A four-component reaction of 2-vinylbenzoic acids, aryldiazonium tetrafluoroborates, the sulfur dioxide surrogate DABCO·(SO₂)₂, and nitriles under photocatalysis in the presence of visible light is developed. This multicomponent reaction works efficiently, promoted by BF₃·OEt₂ with the insertion of sulfur dioxide under mild conditions, leading to sulfonated 1-isoindolinones in moderate to good yields. This route is highly selective, and several competitive pathways are not observed under these conditions. A possible mechanism involving photocatalysis and a Lewis acid is proposed.