Amidinosulphenylation of alkenes

Phenylsulphenamides react chemoselectively with an alkene and a nitrile in the presence of trifluoromethanesulphonic acid to give $\text{N}$-(β-phenylthioalkyl) amidines; in the absence of nitrile an amine is formed.Regioselective 1,2-difunctionalization of alkenes with a nitrogen nucleophile and an alkylthio^1?3 or alkylseleno^1,4 group has attracted a good deal of interest recently, because it presents a simple answer to the lack of nitrogen electrophiles capable of attacking a weak nucleophile such as an alkene.⁵ Reductive or oxidative elimination of the RS(e) group leads to overall addition to or substitution at the alkene by the nitrogen nucleophile (“N”) respectively (Scheme 1).