Kinetic resolution of racemic alcohols catalyzed by minimal artificial acylases derived from l-histidine

Abstract

The artificial acylases, tert-butyldiphenylsilyl ether and tris(trimethylsilyl)silyl ether of N(π)-methyl- N(α)-(2,4,6-triisopropylbenzenesulfonyl)- l-histidinol, are simple and small molecules, which contain only one chiral carbon center that originates from natural l-histidine. Asymmetric acylation of racemic secondary alcohols with isobutyric anhydride induced by these artificial acylases gave optically active isobutyrates and optically active alcohols with an S( k fast-reacting enantiomer/ k slow-reacting enantiomer) value of up to 132. One hydrogen bonding interaction between a sulfonamidyl group of the catalysts and a substrate should be essential for inducing the high level of kinetic resolution through catalytic asymmetric acylation. Furthermore, a reusable polystyrene-bound artificial acylase was developed to examine its practicality.