Carbenoid-mediated elimination of sulfides and selenides. A mild and efficient method for introducing α,β-double bonds to electron-withdrawing substituents

Cycloalkanes bearing both an electron-withdrawing group and an arylsulfenyl or arylselenenyl function in β-position are shown to react with 2 equiv. of a carbenoid species to generate the corresponding Michael acceptor. The reaction occurs under very mild conditions and affords the products in good to excellent yields. The process constitutes a useful alternative to the oxidation/syn-elimination sequence.