Generation of benzosultams via a radical process with the insertion of sulfur dioxide

Abstract

A three-component reaction of 2-ethynylbenzenesulfonamides, DABCO-bis(sulfur dioxide), and aryldiazonium tetrafluoroborates affords sulfonated benzosultams in moderate to good yields. This reaction proceeds through a tandem radical process. DABCO acts as a carrier for single electron transfer, as well as a base to promote the C–N bond formation.