Catalytic Asymmetric Sulfimidation

A direct catalytic imidation of sulfides to sulfimides with N-(p-tolylsulfonyl)iminophenyliodinane (TsNIPh) using a catalytic amount of copper triflate (CuOTf) has been developed. The reaction proceeds with a wide range of sulfides to give the corresponding sulfimides in 50−83% isolated yields. When the reaction is applied to allylic sulfides, the products are the corresponding sulfonamides produced via 2,3 sigmatropic rearrangement of the initially formed allylic sulfimides. In the presence of a chiral bis(oxazoline) as ligand, asymmetric induction occurs to afford the chiral sulfimides (up to 71% ee) and sulfonamides (up to 58% ee). Chloramine T (TsNClNa) can be used in place of TsNIPh for asymmetric sulfimidation, but the ee's are much lower. Some mechanistic observations are described.