Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576243
Title: Allyl fluorides : new syntheses and enantioselective manipulations
Author: Laurenson, James
ISNI:       0000 0004 2743 3500
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2011
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Abstract:
Selectively mono-fluorinated sugars have been acknowledged as useful molecular tools for the study of sugar processing enzymes. The small steric size of the fluorine atom coupled with its high electronegativity make fluorinated sugars ideal candidates to study structure relationships in carbohydrate architecture. We have identified the, as yet, under researched de novo route to fluorinated sugars, whereby the modern tools of asymmetric synthesis are applied to small highly functionalised fluorinated building blocks allowing the possibility of entire libraries of fluorinated sugar analogues to be generated in high enantiomeric excess from a single versatile fluorinated building block. We believe the allylic fluoride moiety represents one of the most versatile and useful functional groups for fluorinated building blocks of this nature. As such, ready access to compounds of this nature is required. Firstly, this work describes the comparison of a new nucleophilic fluorination methodology developed within our laboratory using TBAF.3H2O and KHF2, against a recently reported fluorination reaction by Hou on a small selection of simple allylic bromides. A potential fluorinated building block is then prepared and its compatability with a number of asymmetric dihydroxylation techniques assessed. Secondly, the stereodivergent and stereoselective synthesis of all four diastereoisomers of a versatile C4 fluorinated building block is described. The development and optimisation of a new and facile method for the determination of ee's for these and other fluorinated substrates is also described. Thirdly, a stereodivergent route to an analogous C4 fluorinated building block, via an unusual alkene inversion, developed within our laboratory, is examined in detail. Finally, the development, scope and limitations of a novel methodology for the generation of allylic fluorides using cross metathesis is described. A potentially versatile fluorinated building block is prepared via this method and its suitability as a fluorinated pentose precursor explored.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.576243  DOI: Not available
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