Oxidative kinetic resolution of alcohols using chiral Mn–salen complex immobilized onto ionic liquid modified silica

The supported ionic liquid strategy has been applied for the immobilization of chiral Mn(III) salen complex onto ionic liquid modified silica. Chiral Mn(III) salen complex was immobilized over silica through a thin film of covalently anchored imidazolium ionic liquid. These catalysts were characterized by N2 sorption, XRD, FTIR, DRUV–vis, and elemental analysis. The results showed that the chiral Mn(III) salen complex could be successfully immobilized onto the modified mesoporous materials and that the long-range mesoporous ordering of parent supports was maintained after the immobilization. The immobilized catalyst provided good enantioselectivity and activity in the heterogeneous catalysis of the oxidative kinetic resolution of secondary alcohol and can be recovered and recycled for four times without obvious loss of enantioselectivity and activity. Oxidative kinetic resolutions of meso-diols, hydroxyl ester and primary alcohol were also studied using this catalyst system.

Graphical abstractA supported ionic liquid strategy has been applied for the immobilization of chiral Mn(III) salen complex. This catalyst system was utilized in the oxidative kinetic resolution of a range of alcohols. This catalyst can be recovered and recycled for four times without any loss of activity and enantioselectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide