Efficient, Chemoenzymatic Process for Manufacture of the Boceprevir Bicyclic 3.1.0Proline Intermediate Based on Amine Oxidase-Catalyzed Desymmetrization

The key structural feature in Boceprevir, Merck's new drug treatment for hepatitis C, is the bicyclic 3.1.0proline moiety "P2". During the discovery and development stages, the P2 fragment was produced by a classical resolution approach. As the drug candidate advanced through clinical trials and approached regulatory approval and commercialization, Codexis and Schering-Plough (now Merck) jointly developed a chemoenzymatic asymmetric synthesis of P2 where the net reaction was an oxidative Strecker reaction. The key part of this reaction sequence is an enzymatic oxidative desymmetrization of the prochiral amine substrate.