sulfinyltransfer

Sulfinyltransfer is a class of chemical reactions in which a sulfinyl group (–SO–) is transferred from a donor molecule to an acceptor, forming a sulfinylated product. The transfer can occur to nucleophiles such as amines, alcohols, or thiols, yielding sulfinamides, sulfinyl esters (sulfinates), or other sulfinyl-containing derivatives. This approach enables introduction of a sulfinyl functionality that can serve as a protective group, a chiral auxiliary, or a synthetic handle for further transformations.

Typical sulfinyl donors include sulfinyl chlorides (RSOCl) and related sulfinylating reagents, such as sulfinyl imidazoles or sulfinyl sulfonates. The reaction generally proceeds via nucleophilic attack on the sulfur atom, displacement of a leaving group (for example chloride or imidazole), and formation of the new S–N, S–O, or S–C bond. Reactions are often conducted under basic conditions to neutralize generated acids and promote selectivity.

Common products of sulfinyl transfer include:

- Sulfinamides, formed by transfer to amines (R–SO–NR2).

- Sulfinates or sulfinyl esters, formed by transfer to alcohols or phenols (R–SO–OR').

- N-sulfinyl derivatives, where the sulfinyl group remains attached to nitrogen, as used in protecting-group strategies.

Applications in organic synthesis include the use of sulfinyl groups as protecting groups for amines and as chiral auxiliaries. The p-toluenesulfinyl group, in particular, is employed in enantioselective syntheses, enabling subsequent removal to furnish enantioenriched amines. Advantages of sulfinyl transfer include operational simplicity and the ability to install and later reveal functional handles; challenges include reagent handling, moisture sensitivity, and controlling selectivity in multi-functional substrates.

---