Counteranion-mediated dynamic kinetic asymmetric fluorination to access sulfur-stereogenic center.

Sulfonimidoyl fluorides serve as versatile click linkers and have demonstrated significant utility in the construction of S-stereogenic centers for drug discovery and organic synthesis. Although several established methods enable stereoselective access to these aza-sulfur compounds, achieving direct enantiocontrol in the formation of S(VI)-F bonds remains challenging. Herein, we present a highly efficient strategy to synthesize sulfonimidoyl fluorides through the dynamic kinetic asymmetric fluorination at mild reaction conditions. This one-pot process, involving sequential direct fluorination, hydrolysis and asymmetric fluorination, delivers a wide range of enantioenriched S(VI) compounds with high enantioselectivities. This protocol establishes an ideal platform for concise synthesis of structurally diverse array of S-chirogenic motifs via stereospecific transformations. Mechanistic studies suggest that the steric hindrance and hydrogen-bonding between substrate and phosphate anion are responsible for enantiocontrol.