The First Example of Addition of a 1,2-Dication to a C−C Multiple Bond. Reaction of S−S Dications with Alkenes and Alkynes

Abstract

The reactions of a bicyclic dithioether dication, generated from 1,4-dithiane 1-oxide, with a carbon−carbon multiple bond proceed as conjugated addition of two sulfonium groups and gives rise to derivatives of dithioniabicyclo[2.2.2]octane. The reaction is sensitive to electronic and steric factors. In all cases investigated the reactions of 1,2-disubstituted arylalkene proceed with retention of the relative arrangement of substituents at the double bond of the original alkene. A possible explanation of the obtained results is discussed.