Studies on the Diels-Alder adduct from cyclopentadiene and p-benzoquinone: Biotransformation, enantiomeric excess and absolute configuration

The use of microorganisms or isolated enzymes in synthetic routes has been extensively used by industry and academic research. A great advantage of biotransformation in a synthetic route is highly regio- and enatiosselective control, which can be achieved through microbial catalyzed reaction. Biotransformation is one of the most efficient methods in a production of high purity optical compounds and development of efficient routes for target molecules. Biotransformation by Mucor ramosissimus of enedione 1 gave the keto-alcohol (-)-2 with enantiomeric excess (ee)>99,9% (determined by 1H NMR with [(+)-Eu(hfc)]3) and their epimer (-)-3. Determination of the absolute configuration of epimer (-)-3 was accomplished by controlled reaction and measuring of optical rotation (scheme 1). The fungus M. ramosissimus is a promising species to perform desymmetrization of diketones with high enantioselectivity.