Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed May 23, 2007). PDF text: 231 p. : ill. ; 7.97Mb UMI publication number: AAT 3237598. Includes bibliographical references. Also available in microfilm and microfiche formats.

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MSc., Faculty of Science, University of the Witwatersrand, 2011 / The 2-isopropenyl-2,3-dihydrobenzofuran moiety is found in many naturally occurring compounds including rotenone, a complex pentacyclic molecule isolated from several leguminous plants of the Derris and Lonchocarpus species. Interest in rotenone stems from the fact that it possesses significant pesticidal and piscicidal properties which have been employed for centuries. Furthermore, as it has three stereogenic centres, rotenone poses an interesting and challenging synthetic target for organic chemists. Although various syntheses of this natural compound have been reported, none of these were stereoselective. The first stereoselective total synthesis of rotenone is described in this dissertation. Initially, a model study was conducted in which the simplest of the natural rotenoids, munduserone, was synthesised. The key step in this transformation involves the use of a platinum catalysed 6-endo-hydroarylation reaction of an alkynone intermediate, thus affording munduserone in 6 steps and an overall yield of 23%. We then attended to the synthesis of the more complex rotenoid, rotenone. Rotenone was synthesised by the initial assembly of a chiral (-)-(R)-2-isopropenyl-2,3-dihydrobenzofuran-4-ol moiety, asymmetrically accessible using a stereoselective Pd π-allyl mediated cyclisation of (E)-4-(2,6-dihydroxyphenyl)-2-methylbut-2-enyl methyl carbonate. Having constructed the dihydrobenzofuran in an enantiomeric excess of 94.8%, the chromene part of rotenone could then be synthesised. To this end, the LDA mediated coupling reaction of the formylated dihydrobenzofuran and 1,2-dimethoxy-4-(prop-2-ynyloxy)benzene, gave a secondary alcohol which was subsequently oxidised to the corresponding alkynone, (-)-(R)-(6,7-dimethoxy-2H-chromen-4-yl)(4-methoxy-2-isopropenyl-2,3-dihydrobenzofuran-5-yl)methanone. A 6-endo-hydroarylation reaction was employed as a mild strategy to construct the chromene moiety, (-)-(R)-(6,7-dimethoxy-2H-chromen-4-yl)(4-methoxy-2-isopropenyl-2,3-dihydrobenzofuran-5-yl)methanone. Finally, a deprotection and a base-catalysed intramolecular oxo-Michael addition concluded the first stereoselective synthesis of rotenone in 17 steps and an overall yield of 0.02%

Chan Kin Fai. / "April 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 151-157). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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The impact of fluorine in medicinal chemistry is reviewed in the first chapter of this work and the fluorine gauche effect, which has not been fully exploited in medicinal chemistry, is also discussed. GABAA and GABAB receptors are then presented and the synthesis of neurosteroid antagonists acting at GABAA receptors is reported. The synthesis of such compounds was motivated to explore the mode of action of neurosteroids at GABA receptors. The observation that the C-F bond has a strong preference to align gauche to the C-N+ bond in protonated β-fluoroamines stimulated the enantioselective synthesis of 3-fluoro-GABA enantiomers. This was achieved from L- and D- phenylalanine in six steps and in an overall yield of 31%. The preferred conformations of 3-fluoro-GABA in solution are then explored by NMR analysis and ab initio calculations. The biological evaluation of 3-fluoro-GABA enantiomers on GABA aminotransferase was then investigated and showed that the (R)-enantiomer undergoes HF elimination ten times more rapidly than the (S)-enantiomer, suggesting a preferred binding conformation of GABA on GABA aminotransferase. This study demonstrates that the C-F bond can be used as a chemical probe to reveal the binding conformation of a bioactive amine and this offers exciting prospects for future research. The synthesis of 3-fluoro-GABA from phenylalanine indicated that amino acids are practical starting materials for the preparation of β-fluoroamines. This methodology is applied to L-lysine to generate (2R)-fluorohexane-1,6-diamine. The formation of a diamine of potential interest for catalysis is also observed in this synthesis.

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Thesis (Ph.D.)--Baylor University, 2006. / Includes bibliographical references (p. 93-103).

Thesis (M.S.)--University of Texas at El Paso, 2007. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.