Stereoselective Desymmetrizations by Recombinant Whole Cells Expressing the Baeyer–Villiger Monooxygenase from Xanthobacter sp. ZL5: A New Biocatalyst Accepting Structurally Demanding Substrates

In this work the substrate profile and stereoselectivity of engineered whole cells overexpressing the Baeyer–Villiger monooxygenase from Xanthobacter sp. ZL5 with respect to biotransformations of prochiral substrates is characterized. This enzyme catalyzes the desymmetrization of cyclic ketones bearing different chemical features with stereoselectivity similar to that obtained with a related protein fromAcinetobacter as a prototype representative of the cyclohexanone monooxygenase enzyme cluster. Moreover, this biocatalyst is able to convert sterically demanding substrates previously not transformed by other enzymes with excellent enantioselectivities. These results expand the repertoire of optically pure lactones accessible by whole‐cell biotransformation processes, which are useful intermediates for the synthesis of natural and bioactive products. In addition, we observed a remarkable epoxidation reaction of a non‐activated C=C bond catalyzed by this monooxygenase.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)