Preparation of mesoporous silica-supported chiral amino alcohols for the enantioselective addition of diethylzinc to aldehyde and asymmetric transfer hydrogenation to ketones

Abstract

Optically active (-)-ephedrine, (-)-norephedrine, and (-)-prolinol were immobilized onto cubic mesoporous MCM-48 silica. The immobilized amino alcohols served as a heterogeneous chiral catalyst for the asymmetric addition of diethylzinc to aldehydes and transfer hydrogenation to ketones. The developed catalytic process yielded optically enriches secondary aromatic alcohols with 92-99% conversion and 70-82% enantioselectivity.