Catalytic Enantioselective Protonation of Monofluorinated Silyl Enol Ethers towards Chiral α‐Fluoroketones.

Summary of main observation and conclusion: Described herein is an organocatalytic enantioselective protonation of monofluorinated silyl enol ethers, affording an array of optically active α‐secondary α‐fluoroketones in good to high yields and enantioselectivities, under the catalysis of bifunctional cinchonidine derived squaramide C4. It represents a rare example of facile synthesis of enantioenriched α‐secondary α‐fluoroketones. With D2O as the deuterium source and MeOD as the solvent, the first highly enantioselective preparation of chiral α‐deuterated α‐fluoroketones in >92% deuteration is developed. [ABSTRACT FROM AUTHOR]