Abstract This thesis is concerned with microbially derived cis-3,5-cyclohexadiene-1,2- dihydroxy-1-carboxylic acid and its iron tricarbonyl derivatives as precursors for the efficient and practical synthesis of useful products. The opening chapter consists of a review of the biocatalytic cis-dihydroxylation process including its mechanism and applications in synthesis. In a Chapter 2 the utility of cyclohexadiene iron tricarbonyl complexes to date is outlined, with particular focus on their preparation and reactivity. Synthetic routes towards the synthesis of the natural products gabaculine and carbazole alkaloids are described, followed by the preparation of tarniflu and general methods of decomplexation. Chapter 3 presents the synthesis of novel iron tricarbonyl complexes and studies on their reactivity are disclosed. (Figure A.) Chapter 4 describes the formation of a new rearrangement product of the acetonide protected iron tricarbonyl complexes. In order to validate this process, independent studies with labelled compounds have been employed. Following Myers' procedure for microbial oxidation of p-deutero-benzoic acid, quantities of a novel deutero-diol product were successfully prepared and used to elucidate the mechanism of the rearrangement process. (Figure B) In Chapter 5 the formation of the f]5 cyclohexadienyl complexes is discussed followed by the outcome of the nucleophilic addition products. Chapter 7 provides detailed specific and general procedures for the synthesis of the compounds described within this thesis, along with their characterisation data. The appendices provide analytical support to this thesis and list of publications. Each chapter includes a separate discussion of the results and Chapter 6 provides an overall summary and suggestions for possible future work.

This thesis sought to expand upon the synthetic application of the underexploited ipso, ortho diene cis-diol microbial arene oxidation product from benzoic acid. The microbial oxidation of benzoic acid by mutant strains of bacteria to give the ipso, otho diene cis-diol may be considered to be a green and clean method. This biocatalytic route yields large quantities of an enantiopure chiral building block, which is not assessable via traditional synthetic methods. The fermentation product has seen application towards the synthesis of aminocylitols, which have been tested for their biological activity. Attempts to synthesise the fully oxygenated counterparts, cyclitols, were investigated. Expansion of previous work using a bromine substituted derivative led to a range of cross-coupled and iron co-ordinated products. Finally, a range of novel chiral acids and ketones were synthesised and evaluated for their catalytic activity towards asymmetric epoxidation.

The natural product celastrol (1) possesses a wide array of promising biological activities related to diseases characterized by protein misfolding including those associated with neuronal degradation, inflammation, and cancer. Relevant to cancer, celastrol functions as a non-ATP-competitive inhibitor of heat shock protein-90, providing a potential lead for the development of new inhibitors with improved pharmacology. A laboratory preparation of the small molecule was undertaken to provide access to the unnatural enantiomer of celastrol. The lack of understanding of the chemistry and biology of the growing class of celastroids is attributed to the incompatibility of biologically inspired polyene cyclization strategies to assemble friedelin triterpenoids. As a result of these problems residing at the interface of chemistry and biology, a purely synthesis-based strategy for polyene cyclizations to rapidly construct the pentacyclic core of the friedelin and celastroid natural products has been developed. This efficient strategy is gram scalable culminating in the first total synthesis of wilforic acid (127) and an advanced intermediate capable of delivering celastrol (1) as well as numerous celastroid natural products. Phenols possess broad utility serving as key materials in all facets of chemical industries, especially the pharmaceutical industry. The ideal synthesis of a phenolic compound entails the direct oxidation of an aryl C-H bond remains to be a difficult synthetic challenge. Following our initial report describing the hydroxylation of arenes using phthaloyl peroxide, new peroxide derivatives were investigated to probe their reactivity in an effort to hydroxylate aromatics which were previously unreactive. Electronically poor to moderately rich arenes were successfully hydroxylated with a broad functional group tolerance using 4,5-dichlorophthaloyl peroxide. This protocol has been applied toward the rapid synthesis of phenolic analogs and metabolites of current pharmaceuticals as well as biocides. Mechanistic studies using kinetic isotope effect, competition, and benzylic oxidation experiments indicate that a novel diradical reverse-rebound mechanism is the likely pathway. Further examination of the transition-state using linear free energy relationships with sigma vs. sigma+ values established a linear trend with a low negative rho value (- 3.92) corresponding best using sigma values supporting a diradical reverse-rebound addition. / text