Anders Riise Moen, B. Hoff, L. Hansen
May 24, 2004
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Journal
Tetrahedron-asymmetry
Abstract
Abstract Biocatalytic asymmetrizations of diethyl 3-hydroxyglutarate furnish a route to the enantiomers of ethyl 4-cyano-3-hydroxybutanoate. The enantiopreference of different enzymes has been established by chiral chromatography. Conclusive evidence for absolute configurations has been provided by X-ray crystallographic structure determination of co-crystals of the predominant monoester with (R)-phenylethylamine. The predominant enantiopure monoester produced by ammonolysis of diethyl 3-hydroxyglutarate catalyzed by immobilized lipase B from Candida antarctica (Novozym 435) was ethyl (3S)-4-carbamoyl-3-hydroxybutanoate. This was converted to ethyl (3S)-4-cyano-3-hydroxybutanoate in high yield and enantiomeric excess. Growing cells of Acinetobacter lwoffii gave low ee and predominance of the (S)-enantiomer when used for hydrolysis of diethyl 3-hydroxyglutarate as opposed to previous reports. When Novozym 435 was used for hydrolysis it could be re-used 10 times without loss of activity and selectivity.