Arenesulfonyl

Arenesulfonyl, also called arylsulfonyl, denotes the sulfonyl functional group attached to an aryl ring: ArSO2-. The group is a sulfonyl moiety (SO2) bonded to an aromatic system and is widely used in organic synthesis as a sulfonylating agent and as a removable or temporary protecting group. The aryl ring can be substituted; common examples include p-tolyl, nitroaryl, and phenyl derivatives.

Common derivatives and uses include arylsulfonyl chlorides (ArSO2Cl), which install the sulfonyl group onto nucleophiles such as amines in the formation of sulfonamides (R-NH-SO2-Ar). The tosyl group (p-tolylsulfonyl, Ts) and nosyl group (2-nitrobenzenesulfonyl, Ns) are widely used protecting groups for amines. Tosyl chloride is used to protect amines in organic synthesis; Nosyl chloride similarly provides a removable protection. Aryl sulfonyl chlorides also convert alcohols to arylsulfonate esters (tosylates, nosylates), which are excellent leaving groups in substitutions.

Synthesis and availability: Arenesulfonyl chlorides are commonly prepared by chlorination of arenesulfonic acids (ArSO3H) with reagents such as thionyl chloride or phosphorus oxychloride. They occur as well-characterized reagents in many chemical catalogs, with derivatives including TsCl, NsCl, and others.

In summary, arenesulfonyl groups are versatile in synthesis, enabling protection, activation, and leaving-group strategies, with the ability to tune properties via the aryl substituent.