Generation and characterization of new sulfenate salts via ipso-substitution of azaheterocyclic sulfoxides

New stable sulfenate salts, sodium 2‐pyridinesulfenate 9a and sodium 2‐(3‐trimethylsilyl)pyridinesulfenate 9b, were prepared by the ipso‐substitution reactions of azaheterocyclic sulfoxides (1c/3a and 4a, respectively) with sodium ethoxide or sodium butanethiolate under mild conditions and were characterized by physical and spectroscopic properties. The FT‐IR spectra of compounds 9a and 9b showed characteristic SO absorptions at 870 and 890 cm−1, respectively. These sulfenate salts were converted rapidly to the corresponding sulfinate salts on contact with oxygen. A number of other sulfenates were prepared and trapped by alkylation to give sulfoxides (as were 9a and 9b).