A novel multicomponent sulfonylation of alkenes is described for the assembly of various beta-substituted arylsulfones using cheap and easily available K2S2O5 as a sulfur dioxide source. Of note, the procedure does not need any extra oxidants and metal catalysts and exhibits a relatively wide substrate scope and good functional group compatibility. Mechanistically, an initial arylsulfonyl radical is formed involving the insertion of sulfur dioxide with aryl diazonium salt, followed by...