The first part of this thesis describes the efficient synthesis of several hypervalent iodine(III) compounds. Electron-rich diaryliodonium salts have been synthesized in a one-pot procedure, employing mCPBA as the oxidant. Both symmetric and unsymmetric diaryliodonium tosylates can be isolated in high yields. An in situ anion exchange also enables the synthesis of previously unobtainable diaryliodonium triflates. A large-scale protocol for the synthesis of a derivative of Koser’s reagent, that is an isolable intermediate in the diaryliodonium tosylate synthesis, is furthermore described. The large-scale synthesis is performed in neat TFE, which can be recovered and recycled. This is very desirable from an environmental point of view. One of the few described syntheses of enantiopure diaryliodonium salts is discussed. Three different enantiopure diaryliodonium salts bearing electron-rich substituents are synthesized in moderate to high yields. The synthesis of these three salts shows the challenge in the preparation of electron-rich substituted unsymmetric salts. The second part of the thesis describes the application of both symmetric and unsymmetric diaryliodonium salts in organic synthesis. A metal-free efficient and fast method for the synthesis of diaryl ethers from diaryliodonium salts has been developed. The substrate scope is wide as both the phenol and the diaryliodonium salt can be varied. Products such as halogenated ethers, ortho-substituted ethers and bulky ethers, that are difficult to obtain with metal-catalyzed procedures, are readily prepared. The mild protocol allows arylation of racemization-prone a-amino acid derivatives without loss of enantiomeric excess. A chemoselectivity investigation was conducted, in which unsymmetric diaryliodonium salts were employed in the arylation of three different nucleophiles in order to understand the different factors that influence which aryl moiety that is transferred to the nucleophile. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Accepted. Paper 5: Submitted. Paper 6: Manuscript.</p>

Thesis (Ed.D.)--Teachers College, Columbia University, 1994. / Includes tables. Typescript; issued also on microfilm. Sponsor: Jean Lythcott. Dissertation Committee: Roger O. Anderson. Includes bibliographical references (leaves 174-186).

<p>This thesis summarizes three novel and general reaction protocols for the synthesis of diaryliodonium salts. All protocols utilize mCPBA as oxidant and the acids used are either TfOH, to obtain triflate salts, or BF3•Et2O that gives the corresponding tetrafluoroborate salts in situ.</p><p>Chapter two describes the reaction of various arenes and aryl iodides, delivering electron-rich and electron-deficient triflates in moderate to excellent yields.</p><p>In chapter three, it is shown that the need of aryl iodides can be circumvented, as molecular iodine can be used together with arenes in a direct one-pot, three-step synthesis of symmetric diaryliodonium triflates.</p><p>The final and fourth chapter describes the development of a sequential one-pot reaction from aryl iodides and boronic acids, delivering symmetric and unsymmetric, electron-rich and electron-deficient iodonium tetrafluoroborates in moderate to excellent yields. This protocol was developed to overcome mechanistic limitations existing in the protocols described in chapter two and three.</p><p>The methodology described in this thesis is the most general, efficient and high-yielding existing up to date, making diaryliodonium salts easily available for various applications in synthesis.</p>

This thesis summarizes three novel and general reaction protocols for the synthesis of diaryliodonium salts. All protocols utilize mCPBA as oxidant and the acids used are either TfOH, to obtain triflate salts, or BF3•Et2O that gives the corresponding tetrafluoroborate salts in situ. Chapter two describes the reaction of various arenes and aryl iodides, delivering electron-rich and electron-deficient triflates in moderate to excellent yields. In chapter three, it is shown that the need of aryl iodides can be circumvented, as molecular iodine can be used together with arenes in a direct one-pot, three-step synthesis of symmetric diaryliodonium triflates. The final and fourth chapter describes the development of a sequential one-pot reaction from aryl iodides and boronic acids, delivering symmetric and unsymmetric, electron-rich and electron-deficient iodonium tetrafluoroborates in moderate to excellent yields. This protocol was developed to overcome mechanistic limitations existing in the protocols described in chapter two and three. The methodology described in this thesis is the most general, efficient and high-yielding existing up to date, making diaryliodonium salts easily available for various applications in synthesis.

Thesis (M.Tech.)(Nuclear Medicine) -- Central University of Technology, free State, 2007 / In the South African Health Services (SAHS) it is each health worker’s responsibility to find ways to reduce health care cost and improve health service to the public. The measurement of radioactive iodine uptake (RAIU) by the thyroid gland for diagnostic purposes has been used as early as the 1940s. The 24-hour (hr) iodine-131 (131I) uptake measurement is traditionally used for the calculation of the 131I administered activity for therapy dosage. This entails that the patient’s hospitalisation is prolonged, which increases the costs. The literature also indicates that the 24-hr 131I uptake value can be discarded and only the 6-hr 131I uptake measurement is needed to calculate administered activity for therapeutic dosages for Graves’ patients. Therefore, if it can be confirmed that the 6-hr 131I uptake measurement alone is needed, the SAHS could decrease hospitalisation costs. The overall goal of the investigation was to analyse the 6-hr and 24-hr 131I uptake measurements of patients with Graves’ disease at the Universitas Hospital. The aim was to determine the relationship between the 6-hr and 24- hr RAIU values to establish the therapeutic dosage for Graves’ disease. To achieve the aim, three objectives were set. First, to serve as a background to the investigation, a literature survey relating to the RAIU measurements of patients with Graves’ disease was made. Second, a retrospective analysis was performed by collecting the 6-hr and 24-hr 131I uptake measurements of patients with proven Graves’ disease at the Universitas Nuclear Medicine Department (UNMD). Finally, the data obtained from the retrospective analysis was analysed, summarised and compared to answer the investigation questions. The investigation group included patients with confirmed Graves’ disease who had undergone both the 6- and 24-hr 131I RAIU at the Universitas Hospital from the beginning of 2004 to the end of 2005. Graves’ disease is confirmed by the following factors at the UNMD, namely: Suppressed TSH, elevated T4 and T3 values, an increased uptake on the 99mTc-pertechnetate scan and increased 6- and 24-hr 131I RAIU values. The UNMD statistics show that 178 patients were diagnosed with Graves’ disease during this period. The patients of the investigation group included both male and female patients from different races, ranging from 15-75 years. In order to increase the validity of the investigation, all factors that could influence the accuracy of the 131I thyroid uptake test were excluded. After the exclusion and inclusion criteria had been applied, the final investigation group was made up of 124 Graves’ disease patients. The data obtained from the patient files was noted on the different data sheets (see Appendix A) for further analysis. The information from these data sheets was then used to obtain the investigation results. The Department of Biostatistics of the University of the Free State (UFS) was consulted for recommendations regarding the management of data and the processing of results. All values were summarised by means and Standard Deviations (SD) or percentiles. Mean or median differences were calculated with a 95% Confidence Interval (CI). A regression analysis was made between the 6-hr and 24-hr 131I RAIU values. The highest RAIU value is the best to calculate the therapeutic dosage, as this gives a true reflection of the thyroid function of a Graves’ disease patient. In the investigation group the median of the 24-hr 131I RAIU values was higher than the 6-hr 131I RAIU values. The findings showed that the 24-hr 131I RAIU in most of the investigation group was the highest value and most effective to calculate the 131I therapeutic dosage. At a time when research-based practice is taking on an increasingly important role, it is essential for nuclear medicine departments to make evidence-based recommendations. This investigation found that the correlation between the 6-hr and 24-hr RAIU clearly justified the cost spent on Graves’ disease patients who must stay overnight for the 24-hr 131I RAIU procedure.

This thesis describes novel reaction protocols for the synthesis of diaryliodonium salts and also provides an insight to the mechanism of α-arylation of carbonyl compounds with diaryliodonium salts.  The first chapter gives a general introduction to the field of hypervalent iodine chemistry, mainly focusing on recent developments and applications of diaryliodonium salts. Chapter two describes the synthesis of electron-rich to electron-poor diaryliodonium triflates, in moderate to excellent yields from a range of arenes and iodoarenes. In chapter three, it is described that molecular iodine can be used together with arenes in a direct one-pot, three-step synthesis of symmetric diaryliodonium triflates. A large scale synthesis of bis(4-tert-butylphenyl)iodonium triflate is also described, controlled and verified by an external research group, further demonstrating the reliability of this methodology. The fourth chapter describes the development of a sequential one-pot synthesis of diaryliodonium salts from aryl iodides and boronic acids, furnishing symmetric and unsymmetric, electron-rich to electron-poor diaryliodonium tetrafluoroborates in moderate to excellent yields. This method was developed to overcome the regiochemical limitations imposed by the reaction mechanism in the protocols described in the preceding chapters. Chapter five describes a one-pot synthesis of heteroaromatic iodonium salts under similar conditions described in chapter two. The final chapter describes the reaction of enolates with chiral diaryliodonium salts or together with a phase transfer catalyst yielding racemic products. DFT calculations were performed, which revealed a low lying energy transition state (TS) between intermediates, which is believed to be responsible for the lack of selectivity observed in the experimental work. It is also proposed that a [2,3] rearrangement is preferred over a [1,2] rearrangement in the α-arylation of carbonyl compounds. The synthetic methodology described in this thesis is the most generally applicable, efficient and high-yielding to date for the synthesis of diaryliodonium salts, making these reagents readily available for various applications in synthesis.