Nucleophilic addition-elimination reactions of N-(p-tolylsulphonyl)vinylsulphoximines: preparation of α-methylene nitriles and phosphonates

Treatment of N-(p-tolylsulphonyl)vinylsulphoximines (1) with lithium cyanide in DMF at room temperature leads to efficient formation of α,β-unsaturated nitriles (3), via a Michael addition-proton transfer-elimination process, in which the polarity of the double bond is reversed. Analogous reaction with lithium dimethylphosphonate leads to β-dimethylphosphonyl sulphoximines (7), which are converted to α,β-unSaturated phosphonates (6) by treatment with NaOMe.