Metal-free selenosulfonylation of alkynes: rapid access to β-(seleno)vinyl sulfones via a cationic-species-induced pathway

A novel and convenient method has been developed for the 1,2-selenosulfonylation of alkynes under metal-free conditions. The reaction avoids the need for the pre-prepared Se-S reagents, providing facile access to a series of beta-(seleno)vinyl sulfones with high levels of regio- and stereoselectivity. The key features of this reaction include broad substrate scope, excellent functional-group tolerance, readily available reagents and amenability to gram-scale synthesis. Preliminary mechanistic studies support the proposed cationic-species-induced pathway.