Base-Promoted Ring-Opening Reaction of Sulfonium Salts with Isothiocyanates and Alkyl Nitriles for Accessing 2-Cyanoacrylate Derivatives

An efficient and practical method for the synthesis of S-alkyl-substituted 2-cyanoacrylate derivatives is described. This transformation relies on a base-promoted ring-opening thioalkylation of cyclic sulfonium salts in which C-S bond cleavage and recombination occur smoothly with commercially available isothiocyanates and alkyl nitriles under an air atmosphere, affording the desired products in good to excellent yields. This process operates under mild, transition-metal- and additive-free reaction conditions, showcasing high selectivity and good tolerance to various functional groups.