Efficient Construction of 4-hydroxy-4-arylbutan-2-ones through an Enantioselective Aldol Reaction Mediated by a Recoverable Proline-Based Chiral Ionic Liquid

摘要

Chiral ionic liquid derived from L-proline worked as an excellent organocatalyst for the enantioselective aldol reaction of aromatic aldehydes and acetone. The reaction was conducted in the presence of [BMIM][BF4] as reaction medium. The substrate scope of aldol reaction was successfully explored for various aromatic aldehydes under the mild conditions. The generated aldol products were separated by column chromatography with moderate to good yields as well as enantioselectivities. The main advantage of this catalytic method was that the catalyst and solvent could be recovered at the same time and reused for at least five times with satisfactory performance.