Enzymatic Baeyer-Villiger oxidation of bicyclic diketones

Cyclohexanone monooxygenase from Acinetobacter calcoaceticus was employed for the Baeyer-Villiger oxidation of racemic bicyclic diketones such as the Wieland-Miescher and the Hajos-Parrish diketones and of some of their derivatives. The corresponding lactones were produced in a highly regio- and enantioselective manner. The reactions were carried out using a crude enzyme preparation in aqueous buffer, at room temperature, and the recycling of the expensive coenzyme NADPH was conducted with a second ancillary enzymatic system. The enzymatic process was simple and easy to handle, thus providing a very practical tool to access enantiopure lactones.