Thesis advisor: Kian L. Tan / The acceleration of catalytic asymmetric silylation of syn-diols and triols by use of an azole additive has been developed. By simply adding 7.5-20 mol % of a commercially available small-molecule, 5-ethylthiotetrazole, to a previously reported chiral catalyst, reactions proceed within one hour delivering the desired products with similarly high yields and enantiomeric ratios; there is minimal reaction during the same period when one of the co-catalysts is absent. In an attempt to better understand this silylation mechanism, computational catalyst design and synthetic development were employed. / Thesis (MS) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

by Wong Hei Lam Harry. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 60-67). / Abstract also in Chinese. / Library's copy: Copy 2 imperfect, p. 60-63 missing. / Table of Contents --- p.i / Acknowledgments --- p.iii / Abbreviations --- p.iv / Abstract --- p.v / Abstract (Chinese) --- p.vi / Chapter CHAPTER I --- GENERAL INTRODUCTION / Chapter 1.1.1 --- Different biological activities of enantiomers --- p.1 / Chapter 1.1.2 --- Approach to enantiomerically pure compounds --- p.3 / Chapter 1.1.3 --- Principle of asymmetric synthesis --- p.4 / Chapter 1.1.4 --- Asymmetric catalysis and chiral catalyst --- p.5 / Chapter 1.2.1 --- Asymmetric cyclopropanation: general introduction --- p.6 / Chapter 1.2.2 --- Asymmetric cyclopropanation: initial studies --- p.8 / Chapter 1.2.3 --- Development of c2-symmetric semicorrin and its derivatives --- p.10 / Chapter 1.2.4 --- Bisoxazolines --- p.12 / Chapter 1.2.5 --- Tridentate N donor ligands --- p.13 / Chapter 1.2.6 --- "2,2'-Bipyridines" --- p.14 / Chapter 1.2.7 --- Chiral metalloporphyrin catalyst --- p.15 / Chapter 1.2.8 --- Intramolecular asymmetric cyclopropanation --- p.16 / Chapter CHAPTER II --- DESIGN AND SYNTHESIS OF CHIRAL LIGANDS / Chapter 2.1 --- Development of atropisomeric biaryls --- p.19 / Chapter 2.2 --- "Chiral 2,2'-bipyridine ligands" --- p.19 / Chapter 2.3 --- Design of chiral ligands --- p.22 / Chapter 2.4 --- Synthesis of target ligands: synthetic strategy --- p.22 / Chapter 2.5 --- Attempted synthesis of target ligands via cross-coupling reaction --- p.22

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by Leung Yiu Chung. / "2000 July." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. 98-102). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Over the past two decades and continuing on, carbonyl allylation chemistry has been a very useful and popular tool for the stereocontrolled formation of carbon-carbon bonds in the field of organic synthesis. In the context of natural product synthesis, the efficiency and status of aldehyde allylboration method is only matched by the asymmetric and diastereoselective aldol methodology. Unfortunately, prior to the new millennium, the means to control the absolute stereoselectivity in the addition of allylic boron reagents had been restricted to stoichiometric chiral directors, appended onto the metal center. In 2002, the research groups of Hall and Miyaura reported a new Lewis acid-catalyzed allylboration reaction manifold, which raised intriguing mechanistic questions and also paved the way for a catalytic enantioselective methodology development. Chapter 2 of this thesis details mechanistic studies related to the new Lewis acid-catalyzed allylboration. In this chapter, various control experiments and kinetic studies are presented, the results of which allowed us to propose a hypothesis involving the electrophilic boronate activation as the key factor for the observed rate enhancement. Chapter 3 describes the initial phase of our research to develop a catalytic enantioselective allylboration methodology. We discovered that Brnsted acid catalysts derived from diolSnCl4 complexes were promising catalysts for the asymmetric addition of air and moisture stable and commercially available allylic pinacol boronates. Under this 1st generation catalyst-system, the corresponding homoallylic alcohols were obtained in moderate to good enantioselectivity and excellent diastereoselectivity. The development of a novel chiral Brnsted acid catalyst for the highly enantio- and diastereoselective allylboration reaction methodology is the single most important result to come from this thesis. Chapter 4 outlines the development of the 2nd generation catalyst system. A systematic study of the diol component of the catalyst system led us to arrive at a novel diol nicknamed Vivol on behalf of my contribution. The resulting Brnsted acid derived from VivolSnCl4 now provided the corresponding homoallylic alcohol products in very good to excellent enantioselectivity. Preliminary mechanistic studies along with the X-ray diffraction structure of the catalyst system are also presented. Based on this information, an even better performaning diol (termed F-Vivol) was developed. This 3rd generation catalyst system derived from F-VivolSnCl4 complex was shown to display consistently superior reactivity and selectivity over its 2nd generation predecessor. Chapter 5 describes our efforts to expand the reagent scope of the Brnsted acid catalyzed allylboration methodology. Furthermore, this chapter also describes the successful application of the catalytic process towards the synthesis of simple and complex molecules. Accordingly, the preparation and application of the Brnsted acid-catalyzed addition of 2-bromoallyl boron pinacolate is described. The successful transformation of the corresponding bromo-homoallylic alcohols to a compelling class of -butyrolactones is also presented. The later part of the Chapter presents the synthesis of natural products (+) dodoneine and palmerolide A.

Presented in this thesis are the results obtained from the project: Asymmetric synthesis of substituted 2-aminotetralins. The initial goal was to establish new or improved routes to enantiopure 2-aminotetralin (2-AT) derivatives. The motivation for this project was based on the diverse applications various 2-ATs represent as biologically active compounds. Despite the role of 2-aminotetralins as interesting target molecules, reflected by the massive research activity in the field, no general and cost efficient route has really been established. Chapter 1 in this thesis gives an introduction to 2-ATs as biologically active compounds, as well as a brief survey of the concepts of chirality and asymmetric synthesis. Aziridines are also presented, given their role as key intermediates in our developed strategies (chapters 2-4). In chapter 2, a total synthesis of substituted (S)-2-ATs is presented, starting from natural L-aspartic acid. Two 2-AT derivatives were successfully synthesised, but especially one step (ring-closing to tetralones) proved difficult, providing up to 41% yield only. Chapter 3 is directly based on the experiences we made in the former chapter, and presents an improved route from the same starting point (chiral pool strategy utilising L-aspartic acid). Again we struggled with one specific cyclisation reaction (up to 36% yield), but the remaining steps provided overall good yields. In Chapter 4, a different approach has been targeted, i.e. asymmetric aziridination of 1,2-dihydronaphthalenes. Here, various copper, rhodium and ruthenium catalytic systems were tested with alternative nitrogen sources. While we were able to achieve quite good results for non-substituted 1,2-dihydronaphthalene, substituted substrates provided only mediocre yields and enantioselectivity. Aziridines were selectively ring-opened by catalytic hydrogenation to their respective N-protected 2-ATs in good yields.

Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Rothstein, Hy. Second Reader: Blanken, Leo. "December 2009." Description based on title screen as viewed on January 26, 2010. Author(s) subject terms: Strategy, asymmetric warfare, unconventional warfare, Arreguin-Toft, probability of victory, institutional predisposition, Afghanistan. Includes bibliographical references (p. 77-82). Also available in print.

This dissertation presents research on issues of competition and market structure in economics, and in particular considers the role of asymmetric information in firm competition. This includes asymmetric information among firms, between firms and regulators and between consumers and firms. In the course of this I adapt and expand on recently developed methods for solving, estimating and simulating dynamic models of firm behavior. Finally, this dissertation focuses attention on firms' motivations for and the consequences of horizontal expansion, both in the form of horizontal mergers in a differentiated goods market and in the form of horizontal chain affiliation. This research proceeds in three steps. In Chapter 2 I explore and document consumers growing ability to use new online reputation mechanisms to both share their experiences with a wide variety of firms and gain information from other consumers' shared experiences. In Chapter 3 I present a theoretical model of horizontal mergers in a dynamic industry setting. I use this model to answer a question that increasingly interests antitrust policymakers concerned with innovation: In a concentrated industry, does allowing rival firms to merge increase or decrease total investment? This model has two important features. First, the environment is fully dynamic, and second, I allow mergers to occur endogenously. In Chapter 4, I combine many of the concepts from Chapters 2 and 3 into on piece of research to address the question: why do firms organize into chains? I use of combination of reduced form and structural dynamic methods to examine possible answers to this question in the context of the hotel industry. In particular, I take advantage of recent advances in estimating dynamic industry models to show that there is no evidence in favor of the traditional explanation for horizontal expansion, economies of scale or cost efficiencies. Instead, using a detailed examination of hotel revenue along with firm and market data, I show that chain firms have a substantial demand side advantage resulting from the fact that consumers frequently have little information on firm quality. In this industry, then, asymmetric information seems to not only matter for chain affiliation, it is the only factor that matters. / text

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