Regiodivergent Baeyer–Villiger oxidation of fused ketone substrates by recombinant whole-cells expressing two monooxygenases from Brevibacterium

Microbial Baeyer–Villiger oxidations of fused bicyclic ketones with a cyclobutanone structural motif were investigated using recombinant Escherichia coli cells expressing two monooxygenases from Brevibacterium. In a kinetic resolution process fused ketones were transformed to regioisomeric lactones: ‘normal’ lactones were generated by migration of the more substituted carbon atom and ‘abnormal’ lactones resulted from migration of the less substituted carbon atom. The two Baeyer–Villigerases demonstrated a significantly different stereoselectivity for the regiodivergent biotransformation.