Hf(IV)-catalyzed enantioselective epoxidation of N-alkenyl sulfonamides and N-tosyl imines.

Asymmetric epoxidation of allylic and homoallylic amine derivatives catalyzed by Hf(IV)-bishydroxamic acid complexes is described. Under similar conditions, aldimine and ketimine produced oxaziridines. The sulfonyl group is demonstrated to be an effective directing group for these transformations.