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dc.contributor.advisorO'Hagan, David
dc.contributor.authorSchueler, Martin
dc.description.abstractThe following work describes the synthesis of compounds carrying a vicinal difluoro motif and the evaluation of this structural element to influence the conformation of organic molecules. The synthesis of erythro and threo 1,2-difluoro-1,2-diphenylethane was achieved by bromofluorination and subsequent halogen exchange from stilbene. Oxidative degradation of the phenyl rings allowed to access erythro and threo 2,3- difluorosuccinic acids and a variety of derivatives thereof. The conformations of these compounds were investigated by means of X-ray analysis and NMR spectroscopy. Conformational analysis of derivatives of 2,3-difluorosuccinic acid was carried out using JHFandJHHNMR coupling constants. A clear preference for the conformations in which the two vicinal C-F bonds are gauche emerged from these calculations, which was confirmed by temperature and solvent dependent NMR analyses. The vicinal difluoro motif was incorporated into small peptide structures. In the solid state, a strong preference to align the vicinal C-F bonds gauche to each other was observed and when adjacent to an amide moiety, the C-F bond was found to prefer an anti periplanar orientation with respect to the carbonyl bond. These effects appeared to override steric and electrostatic interactions. The conformation of these fluorinecontaining peptides showed a clear dependence on the stereochemicaol rientation of the C-F bonds, and this appears to be an effective tool for influencing the secondary and consequently tertiary structure in a predictable manner. In order to access single enantiomerso f peptides having the vicinal difluoro, motif, a stereoselectiver oute to R,R and SS 2,3-difluorosuccinic was developed. This involved nucleophilic fluorination of the cyclic sulfates generated from (R, R)- and (SS)- diethyl tartrates and subsequent deoxofluorination of the intermediate fluorohydrins.en_US
dc.publisherUniversity of St Andrews
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported
dc.subject.lcshOrganofluorine compounds--Synthesisen_US
dc.subject.lcshOrganofluorine compoundsen_US
dc.titleThe vicinal difluoro motif in organic chemistry : the synthesis and behaviour of compounds derived from 2,3-diflurosuccinic acidsen_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US
dc.publisher.institutionThe University of St Andrewsen_US
dc.publisher.departmentEdinburgh and St Andrews Research School of Chemistryen_US

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Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported
Except where otherwise noted within the work, this item's licence for re-use is described as Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported