Direct Organocatalytic (alpha)-Fluorination of Aldehydes and Ketones

The first organocatalytic direct (alpha)-fluorination of aldehydes and ketones employing Selectfluor {1-chloromethyl-4-fluoro-1,4diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)} as the fluorine source is reported. (S)-Proline and related derivatives act as organocatalysts to give the corresponding (alpha)-fluoroaldehydes and a-fluoroketones in moderate to good yields (47-78%). The asymmetric inductions are still low (ee <= 36%).