Anionic Phase-Transfer Catalysis for Constructing Chiral Sulfur Centers via Asymmetric Sulfinimidation

Abstract

Chiral anion phase-transfer (CAPT) catalysis has emerged as a powerful strategy for asymmetric catalysis, yet its stereocontrol modes remain largely limited to π-face differentiation or enantiotopic bond selection. The ability to exert stereocontrol through enantioselective recognition of heteroatom lone pairs remains underdeveloped, restricting catalytic access to configurationally stable heteroatom-centered stereocenters. Here, we report a CAPT platform that enables asymmetric sulfinimidation through enantioselective halogenation of prochiral sulfur(II) lone pairs, providing direct access to chiral aryl and alkyl sulfinimidate esters with high enantioselectivity. Mechanistic studies and computational investigations confirm that halogenation is the enantiodetermining step, forming a chiral, configurationally stable sulfinimidoyl fluoride intermediate. Enantioselective oxidation of prochiral sulfides indicates that this CAPT lone-pair recognition platform may be more generally applicable to heteroatom lone pairs. These findings establish lone-pair differentiation as a new mode of stereocontrol in CAPT and expand the conceptual scope of chiral anionic catalysis toward the asymmetric synthesis of chiral organosulfur compounds.