Asymmetric synthesis of chiral 2-hydroxy ketones by coupled biocatalytic alkene oxidation and C-C bond formation

Two different biocatalytic reactions - a C=C cleavage and a C-C forming reaction - were evaluated concerning their application in a reaction sequence. In the overall reaction, an aromatic alkene was converted to a chiral 2-hydroxy ketone. In the first step, the olefin trans-anethole was converted to para-anisaldehyde and acetaldehyde by an aqueous extract of the white rot fungus Trametes hirsuta G FCC 047. The selective oxidative cleavage of the carbon-carbon double bond was achieved using molecular oxygen as a substrate. In a second step p-anisaldehyde was ligated to acetaldehyde to yield either (R)- or(S)-2-hydroxy-1-(4-methoxyphenyl)-propanone. The reaction was catalyzed by the enantiocomplementary C-C bond forming enzymes benzaldehyde lyase and benzoylformate decarboxylase, respectively. (C) 2008 Elsevier B.V. All rights reserved.