S(N)2' addition/1,2-elimination of dimethylsulfonium methylide with epoxy vinyl sulfones: synthesis of exocyclic cross-conjugated dienyl sulfones.

Dimethylsulfonium methylide undergoes S(N)2' addition/1,2-elimination with epoxy vinyl sulfones to generate enantiopure six and seven membered cross-conjugated hydroxy vinyl sulfones. Moderate to excellent yields were obtained for both six and seven membered substrates.