Lipase catalysis in the optical resolution of 2-amino-1-phenylethanol derivatives

Abstract

The lipase PS- and CCL-catalysed resolution of unsubstituted and N-alkyl substituted 2-amino-1-phenylethanols with 2,2,2-trifluoroethyl butyrate or with butyric anhydride and those of the corresponding diacylated 1,2-amino alcohols with 1-alcohols in organic media have been studied. The enzymatic deacylation of diacylated 2-amino-1-phenylethanol stops at approximately 50% conversion yielding the two enantiomers with an e.e. of the order of 100%. Enantioselectivity in the case of N-alkyl substituted compounds is only somewhat lower. Also the enzymatic acylation of 2-amino-1-phenylethanol shows high enantioselectivity when the protection of the NH₂ group with CO₂Et or CO₂CH₂Ph has been used. However, the direct acylation of 2-amino-1-phenylethanol or of its N-alkyl substituted derivatives are slow, the reactions stop before 40% conversion and nonenzymatic aminolysis is usually significant.