Alkylsulfinates

Alkylsulfinates are a class of organosulfur compounds derived from sulfinic acids, in which the acidic proton of the sulfinic acid (RSO2H) is replaced by an alkyl group or by a metal cation to give sulfinate salts with the general formula RSO2−M+. The term often refers to salts such as sodium isopropyl sulfinate (i-PrSO2Na) as well as the corresponding sulfinate esters. The defining feature is the sulfinyl group S(O)2 attached to an alkyl substituent.

Preparation methods for alkylsulfinates vary. A common approach is the oxidation of thiols or thioethers to the corresponding sulfinic acids (RSO2H), followed by neutralization to afford sulfinates (RSO2−M+). They can also be generated by reaction of alkyl organometallic reagents with sulfur dioxide, followed by aqueous workup, or by esterification of sulfinic acids to form sulfinate esters (RSO2OR′).

Reactions and applications of alkylsulfinates center on their nucleophilic sulfur center, enabling C–S bond formation and transfer of the sulfinyl group in various transformations. They can be used to prepare sulfonyl chlorides, sulfones, and sulfinamide derivatives, and serve as sulfinyl transfer reagents in organic synthesis. The stability and versatility of sulfinates make them useful in both radical and ionic sulfinylation processes, as well as in the development of sulfur-containing building blocks for medicinal and materials chemistry.