Dongliang Chang

Regio- and stereoselective hydroxylation of N-substituted piperidin-2-ones with Sphingomonas sp. HXN-200

Abstract High activity, excellent regioselectivity, and opposite enantioselectivity were achieved in the hydroxylation of N -benzyl- and N - tert -butoxycarbonylpiperidin-2-one with Sphingomonas sp. HXN-200. High yield preparations of 4-hydroxypiperidin-2-ones were demonstrated in a bioreactor and in a shaking flask by use of the frozen/thawed cells as biocatalyst. The absolute configuration for the bioproducts was established.

Chemical and enzymatic synthetic methods for asymmetric oxidation of the C-C double bond

A number of synthetically useful methods for asymmetric oxidation of the C–C double bond are briefly reviewed. This includes chemical asymmetric epoxidation, such as Sharpless, Julia, and Jacobsen epoxidation, asymmetric cis-dihydroxylation of olefins, monooxygenase-catalyzed epoxidation, dioxygenase-catalyzed cis-dihydroxylation of aromatics, and trans-dihydroxylation of C–C double bond catalyzed by a monooxygenase and an epoxide hydrolase. The catalytic system, substrate range, enantioselectivity, synthetic application, and scope and limitation of each method are described.

Highly enantioselective hydrolysis of alicyclic meso-epoxides with a bacterial epoxide hydrolase from Sphingomonas sp. HXN-200: simple syntheses of alicyclic vicinal trans-diols

Hydrolysis of N-benzyloxycarbonyl-3,4-epoxy-pyrrolidine and cyclohexene oxide with the epoxide hydrolase of Sphingomonas sp. HXN-200, respectively, gave the corresponding vicinal trans-diols in high ee and yield, representing the first example of enantioselective hydrolysis of a meso-epoxide with a bacterial epoxide hydrolase.