• Chemoenzymatic Formal Total Syntheses of Tetrodotoxin and an Approach to Daphenylline

      Baidilov, Daler; Department of Chemistry
      This thesis describes chemoenzymatic formal total syntheses of tetrodotoxin and a concise synthetic approach to daphenylline. Advanced intermediates for the syntheses of tetrodotoxin reported by the groups of Fukuyama, Alonso, and Sato were prepared. Key steps included toluene dioxygenase-mediated dihydroxylation of either iodobenzene or benzyl acetate and a [4+2] hetero-Diels-Alder cycloaddition/Kornblum–DeLaMare rearrangement sequence to construct a common enone intermediate. The resulting key enone was transformed into Fukuyama's intermediate in four steps, into Alonso's intermediate in six steps, and into Sato's intermediate in seven steps. Fukuyama’s route employed a highly stereoselective allyl cyanate-to-isocyanate rearrangement to install the nitrogen atom at C8a. This protocol was also successfully applied in designing a synthetic avenue to daphenylline. The ABC tricyclic skeleton of daphenylline was successfully constructed in just eight steps starting from readily available (S)-carvone.
    • Synthesis of unnatural analogues of pancratistatin and narciclasine

      Vshyvenko, Sergey; Department of Chemistry (Brock University, 2014-05-07)
      Described herein is the chemoenzymatic synthesis of several different types of unnatural analogues of Amaryllidaceae constituents. Development and refinement of existing and design and execution of new approaches towards the synthesis of C-1 analogues of pancratistatin and A-ring heterocyclic analogues of narciclasine are discussed. Evaluation of the new analogues as cancer growth inhibitory agents is also described