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

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 -lactone.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/680
Date11 1900
CreatorsSunasee, Rajesh
ContributorsDr. D. L. J. Clive (Chemistry), Dr. J. C. Vederas (Chemistry), Dr. C. Cairo (Chemistry), Dr. L. Li (Chemistry), Dr. C. Szymanski (Biological Sciences), Dr. R. Batey (Chemistry, University of Toronto)
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Format4630098 bytes, application/pdf

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