Thesis (Ph. D.)--Brigham Young University. Dept. of Chemistry and Biochemistry, 2007. / Includes bibliographical references.

Thesis (M. Sc.)--University of Alberta, 2009. / Title from PDF file main screen (viewed on Oct. 19, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Chemistry, University of Alberta." Includes bibliographical references.

Thesis (M.A. in National Security Affairs) -- Naval Postgraduate School, June 2006. / Thesis advisor : Richard Grahlman. "June 2006." Includes bibliographical references (p. 61-63). Full text available on Public Stinet.

Thesis (Ph. D.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains xvi, 498 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 75-82).

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Brian L. Pagenkopf. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Michael J. Krische. Vita. Includes bibliographical references.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed May 23, 2007). PDF text: 231 p. : ill. ; 7.97Mb UMI publication number: AAT 3237598. Includes bibliographical references. Also available in microfilm and microfiche formats.

This thesis has focussed on ¹⁸F-fluorination reactions activated by an organomediator, with the aim of broadening the scope of metal-free reactions in ¹⁸F-radiosynthesis. <b>Chapter 1</b> provides an introduction to positron emission tomography (PET) and ¹⁸Fradiochemistry, including radioisotope production and modes of activation in ¹⁸Fradiosynthesis. In <b>Chapter 2</b>, the concept of chirality and its relevance in the context of radiotracer design is introduced. The previously disconnected fields of organomediated asymmetric fluorination and ¹⁸F-radiosynthesis are merged for the first time via investigation of three distinct activation modes: chiral non-racemic secondary amine-mediated asymmetric &alpha;-¹⁸F-fluorination of aldehydes employing [¹⁸F]N-fluorobenzenesulfonimide; use of a phase transfer reagent for asymmetric ¹⁸F-fluorocyclisation and application of a chiral nonracemic ¹⁸F-fluorinating agent, chiral [¹⁸F]Selectfluor bis-triflate. Application of the first of these approaches to the radiosynthesis of the PET tracer (2S,4S)-4-[¹⁸F]fluoroglutamic acid with high d.r. is described. <b>Chapter 3</b> explores the use of hypervalent iodine reagents to mediate the oxidative fluorination of N-arylsulfonamides with nucleophilic fluoride via an umpolung approach. Preliminary studies on translation to radiosynthesis with [¹⁸F]fluoride are also disclosed. In <b>Chapter 4</b>, experimental data is provided for all compounds, as well as analytical and chiral HPLC traces for ¹⁸F-reactions.

A novel camphor-derived hydroxy ketal 138 has been developed as a crural auxiliary, and used to prepare a series of six carboxylic esters of increasing steric bulk. The α-benzylation of this series of esters was achieved with diastereoselectivities of 59 - 83％ d. e. and in 39 - 48％ material yield. These results compared very favourably with those obtained in earlier studies using a regioisomeric analogue as the chiral auxiliary. Computer.modelling studies of the putative enolate intermediate has provided some insight into the possible mode of electrophilic attack at the α-carbon and the roles of the ketal protecting group and the lithium cation in these asymmetric transformations. In a related investigation, based on earlier work, a camphor-derived imino lactone has provided convenient access to α-alkyl α-amino acids, the imino lactone serving as a masked glycine equivalent. Using straight chain primary alkyl iodides [RI; R = Me, Et, Pr, Bu, CH₃(CH₂)₄ and CH₃(CH₄)₅], alkylation of the potassium enolate of the camphor-derived imino lactone was effected with 54 - 89％ d.e. and in 54 - 87％ material yield. Four novel alkylated derivatives were synthesised using isopropyl iodide, sec-butyl iodide and allyl iodide, the latter reagent resulting in both the monoallylated and diallylated products. While very good diastereoselectivities were achieved (83 - 88％ d. e.) in these reactions, the material yields from reaction with the secondary alkyl iodides were low (31- 35％) due, presumably, to their decreased electrophilicity. Computer modelling studies of the enolate were carried out and support the hypothesis of endo attack by the electrophile on the enolate intermediate. These studies also indicate the possibility of coordination of the postassium cation to the endocyclic ester oxygen, thus effectively anchoring the bulky cation away from the reaction site.

This PhD thesis project was concerned with the use of alkali metal amide Brønsted bases and alkali metal alkoxide Lewis bases in (asymmetric) catalysis. The first chapter deals with formal allylic C(sp3)–H bond activation of aromatic and functionalized alkenes for subsequent C–C and C–H bond formations. The second chapter is focused on C(sp3)–Si bond activation of fluorinated pro-nucleophiles in view of C–C bond formations. In the first chapter, a screening of various metal amides, hydrides, and alkyl reagents resulted in the observation that alkali metal amides were effective Brønsted bases to trigger allylic C(sp3)–H bond activation of aromatic alkenes at room temperature. Sodium hexamethyldisilazide was found to be most efficient compared with other s-, p-, d-, and fblock metal amides. This unique transition metal-free methodology was exploited to activate a variety of alkene pro-nucleophiles, which were shown to undergo γ-selective C–C bond formation with various aromatic aldimines as well as one aliphatic substrate. The corresponding homoallylic amine derivatives were obtained in high yields with excellent E:Z ratios. The reaction mechanism was investigated and attempts to detect and/or isolate key intermediates were undertaken. Importantly, it was shown that metal-free superbases of the Schwesinger or Verkade type were not apt to catalyse this challenging C–C bond formation. The asymmetric version of this rare sodium amide catalysis has been achieved by using a commercially available enantiopure bisoxazoline ligand (46% ee). Subsequently, the catalytic use of sodium and potassium amides was applied to the isomerization of terminal aromatic alkenes to generate the thermodynamically more stable internal olefins in excellent yields with high E:Z ratios. Furthermore, functionalized metalloid (B, Si) and metal-free alkenes were found to undergo alkali metal amide-triggered (chemoselective) allylic C(sp3)–H bond activation in view of isomerization and/or C–C bond formation with aldimines. In the second chapter, the catalytic C–Si bond activation of an important difluoromethylation reagent, HCF2SiMe3, was investigated. Here, alkali metal alkoxides were shown to be more effective Lewis base triggers than other metal alkoxides or metal-free superbases. This novel method was successfully used to transfer the nucleophilic difluoromethyl fragment to electrophiles such as a variety of amides and lactams, whereas unsaturated amides failed to undergo the intended conjugate C–C bond formation. In this context, it is noted that the α-hydrogen of certain amides was tolerated. This unprecedented catalytic difluoromethylation of unactivated carbonyl electrophiles was achieved using potassium tert-butoxide at room temperature, and the corresponding fluorinated ‘hemiaminal’ products were obtained in high yields.