Sulfinic Acids and Sulfinic Esters

Abstract

Sulfinic acids are formed readily either by reduction of sulfonyl chlorides with zinc and alkaline solution or by alkaline hydrolysis of thiolsulfonates. Unlike the sulfonic acid, the sulfinic acid retains a lone electron pair on the sulfur atom and hence often behaves as a nucleophile. At the same time, the sulfinic acid is a strong acid and considered to be a key intermediate in the oxidation of the mercaptan to the corresponding sulfonic acid. Although most sulfinic acids are quite reactive, the chemistry of these acids and their esters are relatively unexplored. However, it will not be long before the chemical behavior of sulfinic acid will be uncovered, like that of sulfoxides.