Arylsulfonium salt-mediated SO₂ incorporation to synthesize aryl sulfones

Arylsulfonyl-containing compounds play important roles in pharmaceuticals, agrochemicals, and materials science. Among the available synthetic approaches, SO₂-insertion strategies have emerged as powerful and versatile platforms for constructing sulfonyl-containing molecules from simple precursors. In radical processes, sulfur dioxide surrogates release SO₂, which is trapped by aryl radicals to generate sulfonyl radicals that can subsequently participate in diverse bond-forming reactions. Arylsulfonium salts have attracted increasing attention as aryl-radical precursors because of their facile synthesis, bench stability, and operational convenience. This review summarizes recent progress in arylsulfonium salt-enabled SO₂-insertion reactions, with particular emphasis on the mechanistic divergence of sulfonyl radicals into distinct reaction manifolds, including radical-polar crossover, metal capture, hydrogen-atom transfer/rearrangement, and radical-radical coupling.