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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.

New chiral porphyrin imine was synthesized from (S)-3-benzyl-2-methyl-4phenylbutanal according to dipyrromethane method using trifluoroacetic acid, BF 3 etherate, and p-chloranil. Manganese complex of this chiral porphyrin imine ligand was used as catalyst in the asymmetric epoxidation of styrene derivatives possessing different substituents. Styrene derivatives possessing electron withdrawing groups gave the corresponding chiral epoxides in high yield up to 98% and ee up to 99%. The mechanism for the catalytic asymmetric epoxidation was also discussed based on transfer of oxygen.KEYWORDS asymmetric epoxidation, asymmetric synthesis, chiral epoxides, chiral porphyrin manganese complexes, epoxidation of styrene