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Title: De novo synthesis of fluorinated carbohydrates and their application as probes for fluorine hydrogen bonding
Author: Giufreddi, Guy T.
Awarding Body: Oxford University
Current Institution: University of Oxford
Date of Award: 2011
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Abstract:
In the first part of this thesis, the de novo syntheses of novel fluorinated carbohydrate analogues and the syntheses of fluorosugars from carbohydrate precursors were investigated. The second part was focused on a IH and 19F NMR study of fluorine hydrogen bonding (O-H··F-C) in suitably substituted sugars. Chapter 1 provides a general introduction to fluorine chemistry and summarises the aims and goals of the project. The asymmetric de novo synthesis of fluorinated L-mannitols 73 and L-glucitols 74 is discussed in Chapter 2. The fluoropolyol structures were constructed in nine steps from three two carbon building blocks 75, 76 and 77 with overall yields of up to 26%. The key carbon- fluorine bond was formed using a fluorodesilylation reaction (Scheme i, a). A diversity oriented de novo synthesis of 4-deoxy-4,4-difluoro sugars is presented in Chapter 3. Five di- and trifluorinated hexopyranosides (±)-156 have been synthesised in 8-9 steps with overall yields of up to 29%. A 6-endo-dig gold cyc1isation was of the ynone (±)-159 was used as the key step to prepare the common late stage intermediate glycal (±)-136 (Scheme i, b). Chapter 4 describes the synthesis of methyl 4-fluoro talo- and idopyranosides 218 and 219 from the mannopyranoside 223 and the 2,4-difluoro talopyranoside 220 from the glucopyranoside 222 (Scheme i, c). In Chapter 5, a O-H··F-C hydrogen bonding study of ten of mono-, di- and trifluoro sugars prepared in Chapters 3 and 4 is presented. The selected probes were analysed by lH and 19F NMR spectroscopy and provide new insights into substitution effects on O-H··F-C hydrogen bonding.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.556675  DOI: Not available
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