Recombinant Escherichia coli cells expressing eight Baeyer-Villiger monooxygenases of bacterial origin have been utilized to oxidize prochiral heterocyclic ketones containing a pyran ring system. Within the biotransformation, two stereogenic centers were introduced with high control of enantioselectivity. The chemoselectivity of the enzymatic reaction was found to be high in favor of the Baeyer-Villiger process when using substituted ketone precursors incorporating functional groups labile to oxidation. A significantly different behavior was observed for two groups of monooxygenases with respect to substrate acceptance, which is consistent with our previous classification into two enzyme clusters.