Electrophilic addition of 4′-nitrobenzenesulphenanilide to alkynes in acetic acid. A synthesis of β-acetoxyvinyl sulphides

Abstract

4′-Nitrobenzenesulphenanilide reacts at room temperature with simple alkyl- and aryl-alkynes in acetic acid in the presence of boron trifluoride–diethyl ether to afford products of acetoxysulphenylation in moderate to good yields. The addition products are generally produced with trans-stereospecificity and in a regioselective fashion (Markovnikov orientation). The findings are consistent with a mechanism involving intermediary of thiirenium ions which would result from alkyne attack at the sulphur atom of the anilide complexed with boron trifluoride.