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

A chiral BINOL ligand covalently anchored on silica and mesoporous MCM-41 was synthesized and characterized by powder XRD, FT-IR, N2 adsorption–desorption measurements, TGA and elemental analysis. These anchored ligands were then used to prepare La–Li–BINOL–silica 1a 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.

Chiral BINOL ligand based lanthanum complex supported on Silica and MCM-41 were investigated for enantioselective Henry reaction which gave yield up to 87% of β-hydroxy-nitroalkanes with ee, as high as 84% and the system could be recycled several times without much loss in its performance. Figure optionsDownload as PowerPoint slide