Easy Access to Allylic Sulfones Through Transition-Metal-Free Hydrosulfonylation Of Allenes

A Brønsted acid-mediated addition of (hetero)­aryl and (cyclo)­alkyl sodium sulfinates to N-allenyl derivatives, which proceeds in water, is described under very smooth conditions. This reaction provided a practical and efficient protocol for the regio- and stereoselective synthesis of allylic sulfones in an atom- and step-economic fashion.