The high catalytic activity and reusability of the proline functionalized cage-like mesoporous material SBA-16 for the asymmetric aldol reaction proceeding in methanol–water mixed solvent

Abstract

The cage-like mesoporous material SBA-16 has been successfully functionalized with L-4-hydroxyproline and characterized by Fourier transform infrared (FT-IR) spectroscopy, Small-angle X-ray powder diffraction (XRD), N₂ sorption detection, transmission electron microscopy (TEM), elemental analysis and thermo gravimetric analysis (TGA). This chiral non-metallic catalyst avoided heavy metal pollution during the preparing and using process, and demonstrated high catalytic activity (up to 91%), diastereoselectivity (up to 97 : 3) and enantioselectivity (up to 83%) in the asymmetric aldol reaction between aldehyde acceptors and ketone donors with methanol–H₂O as solvent. Moreover, the synthesized catalyst could be easily separated from the reaction mixture by filtration and reused for up to five runs without any obvious loss of activity, indicating its excellent recyclability.