sulfinyl

The sulfinyl group is a functional group in organosulfur chemistry characterized by a sulfur atom double-bonded to an oxygen atom and single-bonded to two substituents, often written as R-S(=O)-R'. The sulfur atom in this group is in the +4 oxidation state. The group occurs most prominently as part of sulfoxides, where a sulfur atom bears a double bond to oxygen and is connected to two carbon-containing substituents.

In nomenclature, the sulfinyl group is described by the prefix sulfinyl, and compounds bearing this moiety are often named accordingly, for example methylsulfinyl or arylsulfinyl derivatives. Sulfinyl-containing compounds encompass a range of utilities, from simple sulfoxides to more reactive derivatives such as sulfinyl chlorides, which serve as intermediates in organic synthesis.

Synthesis and reactions: sulfinyl compounds are typically formed by the oxidation of sulfides (thioethers) to sulfoxides using mild oxidants such as hydrogen peroxide or peracids. The sulfinyl group imparts polarity and can influence reactivity and stereochemistry; notably, sulfoxides can be chiral at sulfur when the two carbon substituents are different, giving rise to atropisomeric or enantiomeric forms.

Distinctions: the sulfinyl group should not be confused with the sulfonyl group (-SO2-) or the sulfo/sulfate functionalities (-SO3H). Related terms include sulfoxide (R-S(=O)-R'), sulfinic acid (R-S(=O)OH), and sulfinyl derivatives.

See also: sulfoxide, sulfone, sulfinyl chloride.