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

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), N-2 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.