title: Deracemization by simultaneous bio-oxidative kinetic resolution and stereoinversion.
abstract: Deracemization, that is, the transformation of a racemate into a single product enantiomer with theoretically 100% conversion and 100% ee, is an appealing but also challenging option for asymmetric synthesis. Herein a novel chemo-enzymatic deracemization concept by a cascade is described: the pathway involves two enantioselective oxidation steps and one non-stereoselective reduction step, enabling stereoinversion and a simultaneous kinetic resolution. The concept was exemplified for the transformation of rac-benzylisoquinolines to optically pure (S)-berbines. The racemic substrates were transformed to optically pure products (ee>97%) with up to 98% conversion and up to 88% yield of isolated product.
authors.affiliation: Institut für Chemie, Organische und Bioorganische Chemie, Karl-Franzens-Universität Graz, Heinrichstrasse 28, A-8010 Graz (Austria).
authors.forename: Joerg H
authors.initials: JH
authors.lastname: Schrittwieser
authors.forename: Bas
authors.initials: B
authors.lastname: Groenendaal
authors.forename: Verena
authors.initials: V
authors.lastname: Resch
authors.forename: Diego
authors.initials: D
authors.lastname: Ghislieri
authors.forename: Silvia
authors.initials: S
authors.lastname: Wallner
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Fischereder
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Fuchs
authors.forename: Barbara
authors.initials: B
authors.lastname: Grischek
authors.forename: Johann H
authors.initials: JH
authors.lastname: Sattler
authors.forename: Peter
authors.initials: P
authors.lastname: Macheroux
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Turner
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kroutil
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D002384:Catalysis; D007700:Kinetics; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: D000470:Alkaloids
keywords: CC coupling; alkaloids; asymmetric synthesis; deracemization; enzyme catalysis; simultaneous cascades