Photoredox/Chiral Brønsted-Acid-Catalyzed Asymmetric Hydrofluoroalkylation of α,β-Unsaturated Amides with Langlois-Type Reagents

Cooperative photoredox and chiral Brønsted acid catalysis enables the asymmetric hydrofluoroalkylation of α,β-unsaturated enamides with Langlois-type sulfinates. The reaction furnishes α-chiral fluoroalkyl amides bearing CF3, HCF2, C2F5, and C4F9 groups in up to 99% yield and 96:4 e.r. High stereocontrol is retained in the presence of water, allowing these inorganic sulfinates to operate in a predominantly nonpolar medium. Mechanistic studies are consistent with reductive quenching, fluoroalkyl radical addition, and stereocontrolled protonation. The tolerance of this catalytic mode toward hydrated conditions suggests a route to broader use of Langlois-type reagents in asymmetric photoredox chemistry.