Organocatalytic, regioselective nucleophilic "click" addition of thiols to propiolic acid esters for polyme-polymer coupling

Discerning Tastes: The regioselectivity of the nucleophilic addition of thiols to electron-deficient alkynes is controlled by the choice of the solvent (i.e. the polarity of the reaction mixture) and the catalyst. Both thioalkenes and dithianes can be prepared in a rapid reaction that generates no by-products (see scheme). In turn the utility of this reaction is shown for efficient end-group modification of polymers