Stereoselective Oxidation of β-Methyl-sec-alcohols and α-Methylketones by Corynebacterium equi IFO 3730

The enzyme system of Corynebacterium equi IFO 3730 catalyzed the diastereo-selective oxidation of β-methyl-sec-alcohols. For example, only the erythro isomer of 5-methyl-6-tetradecanol was oxidized to the corresponding ketone, the threo-alcohol remaining. Moreover, the resulting ketone was metabolized enantioselectively by the same microbe. Thus, it was possible to obtain optically active α-methylketones. This biochemical kinetic resolution method was applied for some 2-phenyl-3-alkanones, the expected chiral ketones of moderate to high optical purities being obtained. The degradation pathway was deduced to involve Baeyer-Villiger type oxidation, on the basis of the isolation of small amouts of α-phenylethyl alcohol and acetophenone.