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Durham e-Theses
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Chemistry of novel fluorinated alkenes

Bayliff, Andrew E. (1986) Chemistry of novel fluorinated alkenes. Doctoral thesis, Durham University.



The work described in this thesis is concerned with three areas relating to nueleophilic reactions of novel-polyfluorinated alkenes-. a) Very highly strained fluorinated epoxides have been synthesised from bicyclic internal alkenes using Ca(OCl)(_2). These molecules display an almost unprecedented therira.1 and chemical stability. b) Aromatic bifunctional nucleophiles have been reacted with a variety of perfluorinated alkenes and cycloalkenes to give high yielding heterocyclic compounds. These are discussed within a mechanistic framework which my rationalise the product structures. c) Additions of fluoride ion from CsF and TAS-F to fluorinated alkenes in a suitable solvent are shown to yield long-lived fluorocarbanions. N.m.r. observations indicate the systems are whollyin the form of the respective anions and are essentially static on then.m.r. timescale. Competition experiments for a deficiency of CsF are available and can render useful infornmtion on F(^-) affinities. The (^13) and (^19)F n.m.r. spectra of the anions display unusual chemical shift and coupling constant phenomena. The n.m.r. spectra are unchanged over a wide temperature range but at a distinct threshold temperature line broadening occurs. This is indicative of the onset of F exchange on the n.m.r. timescale, is specific to the M(^+)C(^-) system and. therefore, is a guide to the carbanion stabilities. High yielding trapping reactions with simple electrophiles are described but, in some cases F(^-) donation from the carbanion is preferred. This competing reaction is found for particular electrophiles and above the threshold exchange temperature as determined by n.m.r.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:1986
Copyright:Copyright of this thesis is held by the author
Deposited On:08 Feb 2013 13:48

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