Direct organocatalytic α-fluorination of aldehydes and ketones

The first organocatalytic direct alpha-fluorination of aldehydes and ketones employing Selectfluor {1-chloromethyl-4-fluoro- 1,4-diazoniabicyclo[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 alpha-fluoroketones in moderate to good yields (47-78%). The asymmetric inductions are still low (ee <= 36%).