Chiral periodic mesoporous copper(II) bis(oxazoline) phenylene-silica: A highly efficient and reusable asymmetric heterogeneous catalyst

Abstract

We describe the preparation of an effective and reusable heterogeneous asymmetric catalyst. A novel chiral periodic mesoporous phenylene–silica containing high density of bis(oxazoline) moieties is prepared by co-condensation method with 1,4-bis(triethoxysilyl)benzene. After copper(II) coordination, the material is extremely efficient on the kinetic resolution of the 1,2-diphenylethane-1,2-diol with persistent high enantioselectivities (91 - > 99%) and yields (46–43% in maximum 50% resolution) at least for five consecutive cycles. Characterization of the material after the catalytic experiments showed that the heterogeneous catalyst was very robust keeping the integrity of the structure.