Preparation and Characterization of Chiral Oxazaborolidine Complex Immobilized SBA-15 and Its Application in the Asymmetric Reduction of Prochiral Ketones

Abstract

The immobilization of chiral oxazaborolidine complex in the well-ordered mesochannels of SBA-15 is demonstrated by a postsynthetic approach using 3-aminopropyltriethoxysilane as a reactive surface modifier. The immobilized catalysts are characterized by various techniques, such as XRD, nitrogen adsorption, HRSEM, UV/Vis diffuse reflectance spectroscopy, and FTIR spectroscopy. The catalysts are used for the enantioselective reduction of aromatic prochiral ketones. The activity of the chiral oxazaborolidine complex immobilized SBA-15 catalysts is also compared with that of the pure chiral oxazaborolidine complex, which is a homogeneous catalyst. It is found that the activity of the chiral complex immobilized SBA-15 heterogeneous catalyst is comparable with that of the homogeneous catalyst.