sulfonyls

Sulfonyls refer to the sulfonyl group, a functional group with the connectivity R-S(=O)2-R' (often written as -SO2-), where a sulfur atom is doubly bonded to two oxygens and singly bonded to two substituents. The sulfonyl group is highly polar and strongly electron-withdrawing, which influences the acidity, basicity, and reactivity of adjacent atoms in a molecule. It can be attached to carbon, nitrogen, or other heteroatoms, giving rise to a range of derivative classes.

Common sulfonyl derivatives include sulfonyl chlorides (R-SO2-Cl), sulfonyl fluorides (R-SO2-F), sulfonamides (R-SO2-NR'R''), sulfones (R-SO2-R'), and sulfonate-protected amines such as tosyl and nosyl derivatives. Sulfonyl chlorides are reactive electrophiles used to install the sulfonyl group and to form sulfonamides and sulfonate esters; they hydrolyze readily in water to give sulfonic acids and hydrogen chloride. Sulfonyl fluorides are comparatively stable and find use in specialized covalent-modifier and click-type chemistries, including SuFEx reactions. Sulfonamides are a broad class of compounds where the sulfonyl group is bonded to nitrogen, prevalent in pharmaceuticals and protecting-group chemistry. Sulfones feature two carbon-containing substituents bonded to the sulfonyl group and are important in polymers and medicinal chemistry. Tosyl (p-toluenesulfonyl) and nosyl (2-nitrobenzenesulfonyl) groups are widely employed as amine protecting groups.

Applications span pharmaceuticals, dyes, polymers (notably polysulfones), and protective-group strategies. Safety concerns include moisture sensitivity and corrosivity of sulfonyl chlorides, which release acids upon hydrolysis and require appropriate handling and disposal.