Visible-light mediated sulfonylation of thiols via insertion of sulfur dioxide

A simple and efficient visible-light mediated synthesis of thiosulfonates via a radical-radical coupling of sulfenyl radicals and arylsulfonyl radicals was developed. The reaction of thiols, aryldiazonium tetrafluoroborates and DABSO proceeded at room temperature using 5 mol% eosin Y. The reaction displayed wide functional group tolerance and delivered the unsymmetrical thiosulfonates in good to excellent yields.