Synthesis of chiral sulfilimines by organocatalytic enantioselective sulfur alkylation of sulfenamides

Sulfilimines are versatile synthetic intermediates and important moieties in bioactive molecules. However, their applications in drug discovery are underexplored, and efficient asymmetric synthetic methods are highly desirable. Here, we report a transition metal–free pentanidium-catalyzed sulfur alkylation of sulfenamides with exclusive chemoselectivity over nitrogen and high enantioselectivity. The reaction conditions were mild, and a wide range of enantioenriched aryl and alkyl sulfilimines were obtained. The synthetic utility and practicability of this robust protocol were further demonstrated through gram-scale reactions and late-stage functionalization of drugs.