L-Proline in an ionic liquid as an efficient and reusable catalyst for direct asymmetric alpha-aminoxylation of aldehydes and ketones

Proline-catalyzed direct asymmetric alpha-aminoxylation of aldehydes and ketones in the room temperature ionic liquid 1-n-butyl-3-methylimidazolium tetrafluoroborate achieved high yields and high enantioselectivities, even when just 1-5% of proline was used as the catalyst; immobilisation of the catalyst in an ionic liquid phase offers simple product isolation and the reuse of the catalytical system at least four times in subsequent reactions.