title: Chirally functionalized SBA-15 as efficient heterogeneous catalyst for asymmetric ketone reduction.
abstract: Chiral amine catalyst was synthesized using (1R, 2S)-(-)-norephedrine and 5-chlorosalicylaldehyde by reductive amination. The structure of the catalyst was confirmed using 1H-NMR and 13C-NMR spectroscopic method. The catalyst was immobilized onto SBA-15 via covalent bonding using 3-chloropropyltrimethoxysilane as a reactive surface modifier under reflux condition using toluene as a solvent. The supported chiral catalyst was characterized using various physico-chemical techniques like XRD, SEM, N2 adsorption isotherm, FTIR and UV-DRS to study the morphology, pore dimension, functional group analysis and catalyst loading in the mesoporous material. The immobilized catalyst was studied for prochiral ketone reduction using 30 mol% of chiral catalyst and boranedimethylsulphide as a stoichiometric reductant in toluene under inert atmosphere for 30 minutes. Secondary alcohols were formed up to 79% enantiomeric excess for selective ketones. Catalyst was recycled from the reaction mixture and used for further reaction without much effect on the catalytic conversion.
authors.affiliation: Organic and Polymer Synthesis Laboratory, Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015, Tamilnadu, India.
authors.forename: Umesh
authors.initials: U
authors.lastname: Balakrishnan
authors.forename: Sivan
authors.initials: S
authors.lastname: Velmathi