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. (C) 2014 Elsevier Inc. All rights reserved.