Basicity and nucleophilic reactivity of carbonyl-stabilized sulphimides

Abstract

The basicity of N-acyl-SS-dialkylsulphimides was estimated by measurement of the apparent pK_a values of the corresponding iminosulphonium halides. Electron-withdrawing substituents on acyl carbon decrease the pK_a value of substituted acesyisulphimides, and Hammett plot gave ρ 0.8 for para-substituted benzoylsulphimides. Inductive effects of S-alkyl groups on the basicity of nitrogen were also studied in terms of the correlation with alkyl reactivity ratios. Correlation of the pK_a values of the sulphimides with their nucleophilic reactivity towards benzoyl chloride was also examined.