Catalyst-free synthesis of 3-sulfone nitrile from sulfonyl hydrazides and acrylonitrile in water

A novel catalyst-free sulfonation reaction for synthesizing 3-sulfone nitrile compounds from sulfonyl hydrazides and acrylonitriles in water, without any metal catalyst, ligand or organic solvent, was demonstrated. This catalyst-free protocol provides a new synthetic method for the construction of 3-sulfone nitrile compounds with excellent yields. The D₂O experiment adequately proved that the catalyst-free sulfonation reaction occurs via a Michael addition mechanism and that the hydrogen of 3-sulfone nitrile comes from water.