Alkali Carbonates Improve β,β-Diaryl Serine-Catalyzed Enantioselective α-Fluorination of β-Dicarbonyl Compounds.

Herein, we report the highly enantioselective α-fluorination of both cyclic and acyclic β-dicarbonyl compounds, including β-diketones, β-ketoesters, and β-ketoamides. The reactions with β,β-diaryl serines as primary amine organocatalysts were enhanced by adding alkali carbonates, such as Na 2 CO 3 or Li 2 CO 3 , and enabled the reaction to be conducted with only 1.1 equiv of Selectfluor. The optimal conditions afforded the α-fluorinated β-dicarbonyl compounds in 50-99% yield with excellent enantioselectivity (up to 98% ee ).