No description available.

No description available.

No description available.

No description available.

This thesis is concerned with the free-radical addition of nitrogen, silicon and oxygen containing compounds to fluoroalkenes and the chemistry of some of the adducts produced. Free-radical adducts of many amines cannot be produced directly since nucleophilic attack on the fluoroalkene is often the preferred reaction pathway. An alternative route to primary and secondary mono-amine adducts via N-trimethylsilylamines has been developed. An alternative synthesis of di-amine adducts via amides has met with some success. Free-radical additions of organosilicon compounds to fluoroalkenes have produced a variety of fluorosilicon adducts. The chemistry of some of these adducts has been investigated. Work with mono- and di-oxygen functional compounds has provided information on the scope and limitations of this type of free-radical addition reaction. The dehydrofluorination of ether/hexafluoropropene mono- and di-adducts has been investigated and some novel dienes have been produced. Polymers containing amide or ether groups added to hexafluoropropene under free-radical conditions. The use of a solvent dramatically increased the degree of this incorporation. The electrochemical fluorination of cyclic ether/hexafluoropropene di-adducts has been investigated. Good recoveries of highly fluorinated products were obtained, indicating that these types of adducts are good starting materials for electrochemical fluorination.

The work contained in this thesis is divided into three sections detailing the formation of fluorinated dienes and some aspects of their chemistry: a) Through cyclic voltammetry, an electrochemical investigation was carried out to determine the reduction potentials of several easily accessible perfluorinated alkenes. Following this, sodium amalgam was successfully used as a single electron transfer agent in order to reduce a number of these fluoroalkenes by means of selective defluorination. This has enabled a series of perfluorinated alkadienes to be prepared cleanly in good yield. A study of a variety of other means of defluorination was also investigated. b) These dienes have been subjected to attack by mono- and bi functional nucleophiles in high yielding reactions. This has enabled an unusual perfluorinated diepoxide to be synthesised which displays remarkable thermal stability. A number of novel pyrrole and pyrrolo-quinoline derivatives have also been made from a series of substituted anilines and these are discussed within a mechanistic framework in order to justify the product distributions. Finally, the reaction between potentially bi- functional carbon nucleophiles and these perfluorinated dienes has been used as a means of synthesising a series of poly(perfluoroalkyl)- substituted cyclopentadienyl anions including the pentakis(trifluoromethyl)-cyclopentadienyl anion, the formation of which could proceed by an unusual cyclisation and elimination mechanism. c) Charge transfer salts have been prepared by complexation of decamethylferrocene with various fluorinated dienes. These salts have been the subject of X-ray crystallographic and molecular magnetic susceptibility studies. No signs of organic ferromagnetism were observed.

Thesis (Ph. D.)--Princeton University, 1933.

Thesis (Ph. D.)--Princeton University, 1933.

In this thesis, C-F bond activation and C-F bond construction under platinum and iridium catalysis is described. Chapter 1 provides a general introduction on the use of transition metal catalysis for the formation and activation of Csp³-F bonds in organofluorine compounds. In Chapter 2, an investigation on the reactivity of allylic fluorides, under platinum and palladium catalysed alkylation conditions, is presented. The relative reactivity of fluoride versus other commonly used leaving groups was compared via internal competition experiments. Fluoride showed a different reactivity profile, when subjected to Pt and Pd catalytic systems. Based on the observed reactivity trend, a Pd-catalysed fluorination reaction of allylic alcohol derivatives was successfully developed, within the group. In Chapter 3, a new iridium catalysed fluorination using branched, E- or Z-linear allylic carbonates is described. The catalyst [Ir(COD)Cl]₂ leads to an unexpected regio- and stereoretentive selectivity, affording fluorinated products not accessible via palladium catalysis. The effect of a fluoride additive on the selectivity of the Ir-catalysed alkylation reaction is also presented. A highly efficient ¹⁸F-fluorination variant for this new catalytic transformation is reported. Chapter 4 gives full experimental procedures and characterisation data for all compounds.

The aim of this thesis was to investigate the synthesis and the conformational analysis of fluorinated pyrrolidines. We focused on two strategies namely, the iodoamination and fluoroamination of fluorinated precursors. Iodoamination Our first approach for the synthesis of fluorinated pyrrolidines relied on the iodocyclisation of allylic fluorides bearing pendant nitrogen nucleophiles. These allylic fluorides were obtained by fluorodesilylation of suitably functionalised allylsilanes. After validation of this methodology, the scope and limitations of the iodoamination were investigated. Furthermore, we were able to probe the influence of the fluorine moiety on the level of diastereocontrol of the cyclisation. Fluoroamination The second route focused on a key reaction: an unprecedented electrophilic fluoroamination of an aminated allylsilane. From a mechanistic point of view, the presence of the silyl group act as a 1,2-dipole and activate the double bond towards electrophilic fluorination. This methodology required the initial screening of a silyl directing group that would promote electrophilic addition, without subsequent desilylation. Finally, we investigated the level of diastereocontrol displayed by these cyclisations as a function of the E/Z geometry of the starting aminated allylsilane. Conformational analysis Moreover the 3-fluoropyrrolidines obtained via iodoamination served to investigate the stereoelectronic influence of the fluorine gauche effect on ring conformations. Solid state single crystal X-ray analysis and solution phase NMR spectroscopy were used for this purpose. Due to complicated conformational analysis of saturated five-membered rings in solution, 1D 19F-1H heteronuclear nOe (HOESY) experiments have been optimised for applications to this type of small molecules. These have been employed to estimate 19F-1H internuclear distances and were combined with vicinal 3JFH and 3JHH scalar coupling constants in order to analyse the ring conformations.