Methodology and natural product synthesis: carbocycles, culpin and sorbicillactone A

• Author / Creator

  Sunasee, Rajesh

• The first chapter of this thesis describes the development of a general
  method for indirectly effecting radical carbocyclization of an alkyl chain onto an aromatic ring. This process involves a Birch reductive alkylation of aromatic tert-butyl esters, chromium(VI)-mediated oxidation and radical cyclization. The cyclized products are easily aromatized by Saegusa oxidation and treatment with bismuth trichloride. This method forms five- and six-membered benzo-fused carbocycles. Modification allows both formation of non-phenolic products, and the introduction of an additional substituent on the original aromatic ring. The second chapter describes a method for converting tert-butyl benzoates or tert-butyl 1-naphthoates into derivatives having a substituted alkyl group in a 1,4-relationship to an alkyl, aryl, alkenyl or alkynyl group. Key steps in the process involve addition of an organometallic species to a cross-conjugated cyclohexadienone followed by treatment with bismuth trichloride, which results in spontaneous decarboxylative aromatization. The method was successfully applied to the synthesis of the antimicrobial fungal metabolite culpin. The last chapter of this thesis describes synthetic studies towards the marine antileukemic alkaloid, sorbicillactone A. Studies towards the core structure of sorbicillactone A have resulted in a new method of desymmetrization
  of cross-conjugated cyclohexadienones. The key step involves a highly
  diastereoselective iodoetherification and radical cyclization, which affords a
  product that can be elaborated into a γ-lactone.

• Subjects / Keywords

  • Bismuth trichloride
  • Sorbicillactone A
  • Carbocycles
  • Culpin
  • Desymmetrization

• Graduation date

  Fall 2009

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3H72P

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.