Sulfones

Sulfones are a class of organosulfur compounds characterized by the sulfonyl group, R-S(=O)2-R', in which sulfur bears two carbon substituents and two double-bonded oxygens. The sulfonyl group is in the +6 oxidation state and imparts high polarity and notable chemical stability. R and R' can be alkyl or aryl groups, and sulfones can be symmetric or unsymmetric.

Most sulfones are prepared by oxidation of sulfides (thioethers) to sulfoxides and then to sulfones using oxidants such as hydrogen peroxide, oxone, or m-chloroperbenzoic acid. Other routes include reactions of sulfonyl chlorides with organometallic reagents or rearrangements that generate the sulfonyl linkage. In synthesis, sulfones are employed in multiple carbon–carbon bond-forming sequences, including the Julia–Kocienski olefination and related transformations.

Sulfones are chemically robust and highly polar due to the two S=O bonds. They typically exhibit high boiling and melting points, low volatility, and solubility that depends on substituents. The sulfone linkage can be incorporated into polymers to enhance rigidity and thermal stability, and sulfone-containing small molecules often serve as precursors or intermediates in organic synthesis.

Reactivity centers around the alpha position to the sulfone, where acidic protons can form sulfone-stabilized carbanions used in diverse reactions. Sulfones are widely used as monomer units or linkages in high-temperature polymers such as polysulfones (PSU), polyethersulfones (PES), and polyphenylsulfones (PPSU). Simple examples include dimethyl sulfone and diphenyl sulfone, which find use as specialty solvents and intermediates. Some sulfones also occur in drugs and agrochemicals.

Safety considerations align with standard chemical hygiene; some sulfones and related reagents are irritants, and handling oxidants requires care.