Chiral lanthanum-lithium-binaphthol complex covalently bonded to silica and MCM-41 for enantio selective nitroaldol (Henry) reaction

A chiral BINOL ligand covalently anchored on silica and mesoporous MCM-41 was synthesized and characterized by powder XRD, FT-IR, N-2 adsorption-desorption measurements, TGA and elemental analysis. These anchored ligands were then used to prepare La-Li-BINOL-silica la and La-Li-BINOL-MCM-41 1b complexes. The immobilized catalysts having lanthanum content around 0.12-0.18 mmol/g were tested as enantioselective catalyst for Henry reaction and ee 55-84% were found which were comparable to its homogeneous counterpart. The solid catalysts can be reused by simple filtration and recycled several times without much loss in performance. (c) 2005 Elsevier B.V. All rights reserved.