NH4I-Promoted and H2O-Controlled Intermolecular Bis-sulfenylation and Hydroxysulfenylation of Alkenes via a Radical Process

An NH4I-promoted and H2O-controlled intermolecular difunctionalization of alkenes for the synthesis of bis-methylsulfane and β-hydroxysulfides is presented. Mechanistic investigation revealed the reaction proceeds via methylthiyl radical addition to C═C of alkenes to give a carbon-centered radical and immediately cyclize to a thiiranium ion, followed by combination with H2O to afford β-hydroxysulfides in 52–89% yields with chemo- and regioselectivities. In the absence of water, 1,2-disulfenylation takes place to give bis-methylsulfane in moderate to good yields.