Catalyst-free sulfonylation of activated alkenes for highly efficient synthesis of mono-substituted ethyl sulfones in water

A catalyst-free sulfonylation reaction of activated alkenes with sulfonyl hydrazides was efficiently developed under mild and environmentally benign conditions, in water without any ligand or additive. The reaction gave a range of structurally diverse monosubstituted ethyl sulfones with excellent yields, in which the by-product was nitrogen.