Regio- and Stereoselective Synthesis of β-Methylthio Vinyl Triflates.

Vinyl triflates are commonly employed as electrophilic vinyl sources in complex synthesis. The triflation of enolates is commonly required for the preparation of vinyl triflates, generally under strongly basic conditions. Herein, the reaction between alkynes and dimethyl(methylthio)sulfonium trifluoromethanesulfonate is presented, which leads to the development of a facile synthesis of β-methylthio vinyl triflates in a chemo-, regio-, and stereoselective manner under neutral and extremely simple conditions.