Aminosulfoxide

Aminosulfoxide is a term used for organic compounds that contain both an amino group and a sulfoxide moiety within the same molecule. The most common structural motif is the sulfinamide, with a general formula R-S(=O)-NR'R''. In this context, primary sulfinamides have an NH2 substituent on nitrogen, while N-substituted sulfinamides have one or two organic groups on nitrogen. The simplest and best-known member in practical chemistry is tert-butanesulfinamide, a widely used chiral auxiliary.

Synthesis and scope are centered on forming the S(=O)-N bond of a sulfinamide. A general route is the reaction of a sulfinyl chloride (R-S(=O)-Cl) with an amine, which furnishes the corresponding sulfinamide. Other methods include oxidation of thioamides under suitable conditions. The class is structurally diverse, with a range of alkyl, aryl, and heteroatom substituents allowing tuning of steric and electronic properties.

Properties and reactivity are dominated by the polar S(=O) bond and the N–H (or N–R) functionality. Sulfinamides are typically stable and can be handled as solids or liquids depending on substituents. The N–H bond, when present, can be moderately acidic and may be selectively manipulated in synthesis. Deprotection or removal of the sulfinyl auxiliary can liberate primary or enantioenriched amines, depending on the procedure used.

Applications of aminosulfoxides are most notable in asymmetric synthesis. Ellman’s sulfinamide (tert-butanesulfinamide) is a prominent chiral auxiliary enabling the preparation of enantioenriched amines and related products.

See also: sulfoxide, sulfinamide, sulfinyl chloride, Ellman sulfinamide, tert-butanesulfinamide.