Enzymatic Resolution of Chiral 2-Hydroxy Carboxylic Acids by Enantioselective Oxidation with Molecular Oxygen Catalyzed by the Glycolate Oxidase from Spinach (<i>Spinacia oleracea</i>)

The enzymatic oxidation of a variety of saturated and unsaturated aliphatic derivatives of racemic 2-hydroxy acids <b>1</b> to their 2-oxo acids <b>2</b> with molecular oxygen catalyzed by the glycolate oxidase from spinach (<i>Spinacia oleracea</i>) was shown to proceed highly enantioselectively. Thus, the glycolate oxidase-catalyzed kinetic resolution provides a convenient biocatalytic method for the preparation of enantiomerically pure (<i>R</i>)-2-hydroxy acids. The absolute configuration of the (<i>R</i>)-2-hydroxy acid <b>1b</b> was assigned by comparison of the measured optical rotation value with that of the literature data and by application of the exciton-coupled circular dichroism method (ECCD) on its bichromophoric 2-naphthoate 9-methylanthryl derivative <b>3b</b>. These results establish the ECCD method as a convenient microscale chirooptic tool for the configurational assignment of 2-hydroxy acids.