RSO2R

RSO2R is a shorthand notation for a dialkyl sulfone functional group, defined by the formula R-S(=O)2-R. It denotes the sulfone moiety in which sulfur is in the +6 oxidation state and is bonded to two oxygen atoms and two carbon substituents. The two substituents R can be alkyl or aryl groups, and the term covers a wide family of sulfones, including simple dialkyl sulfones such as dimethyl sulfone and diphenyl sulfone. Sulfones differ from sulfones related to sulfoxides in that they contain two S=O bonds, rather than a single S=O bond.

Structure and properties: In sulfones, the sulfur atom adopts a tetrahedral geometry around the S center due to the two double-bonded oxygens and the two carbon substituents. The group is highly polar and electron-withdrawing, which stabilizes adjacent carbanions and influences reactivity in various carbon–carbon and carbon–heteroatom bond-forming processes. The R groups influence solubility, melting point, and compatibility with other reagents.

Synthesis and occurrence: Sulfones are commonly prepared by oxidation of sulfides (thioethers) with oxidants such as hydrogen peroxide, peracids, or oxone, progressing from sulfoxide to sulfone with stronger oxidation. They also appear as functional motifs in natural products, pharmaceuticals, and industrial polymers. Examples include dimethyl sulfone (R = Me), diethyl sulfone (R = Et), and diphenyl sulfone (R = Ph).

Applications: The RSO2R motif is valuable in organic synthesis as a strong electron-withdrawing group that stabilizes carbanions, enabling transformations such as sulfone-groups-directed couplings and eliminations. It also serves in the preparation of sulfone-containing polymers (polysulfones) and as building blocks for medicinal chemistry, where sulfone moieties are common in drug scaffolds.

Safety and handling: Sulfones range from relatively inert to mildly irritant depending on the specific compound. Standard laboratory safety practices apply, including use of gloves and eye protection, with attention to material-specific hazard data.