We report the atom-economic and environmentally friendly synthesis of Z-β-sulfonyl-a,β-unsaturatedcarbonylcompounds in water. The mechanism study reveals that the hydrosulfonylation of alkynylcarbonyl compounds with sulfinic acids proceeds via a mechanism that features a sulfinic acid molecule protonating an alkynyl motif to form the ethenium intermediate, which subsequently reacted with a sulfonyl