Regio- and Stereoselective Synthesis of (E)- and (Z)-Vinylic Sulfones and Their Conversion to the Corresponding Allylic Sulfones

(E)- and (Z)-vinylic sulfones were prepared regio- and stereoselectively from 1-alkenes or 1-alkynes in high yields via iodosulfonization in AcOEt-H2O. The vinylic sulfones thus prepared were converted to the corresponding allylic sulfones by treatment with DBU. Stereochemistry of the conversion was discussed.