Sulfinic acids are oxoacids of sulfur with the structure RSO(OH). In these organosulfur compounds, sulfur is pyramidal, thus the acids are chiral.
Because these acids are often fragile, they are often prepared in situ by acidification of the corresponding sulfinate salts, which are robust. These salts are generate by reduction of sulfonyl chlorides.[1] Alternative routes include treating Grignard reagents with sulfur dioxide. Transition metal sulfinates are also generated by insertion of sulfur dioxide into metal alkyls, a reaction that proceeds via a metal sulfur dioxide complex.
An example of a well-studied sulfinic acid is phenylsulfinic acid. A commercially important sulfinic acid is thiourea dioxide.[2]