Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"C-C bond formation"”.
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Studies in Selective C-C Bond Formation via Borylation and Dehydrogenation
Three stories of C-C bond formation are presented. First, we attempt to harness the Lewis acidity of boron to induce chemo- and regioselectivity in two fundamental organic reactions (Chapter 1). We explore 1,2-difunctionalization of alkenes via formation of a three-membered cyclic intermediate with …
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Studies in palladium and rhodium catalysis: synthetic strategies for C–C bond formation
… and rhodium catalysis for carbon-carbon bond formation. Chapter 1 involves the synergistic use of tetrabutylammonium acetate (NBu4OAc) with palladium catalysis to expand on the synthesis of dibenzofurans via C-H activation. Dibenzofuran and its derivatives are ubiquitous and important …
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1. C-C Bond Formation via Soft Enolization and Umpolung-like Chemistry 2. Electrophilic Fluorination of Organozinc Reagents
… methodology development towards convenient C-C bond and C-F bond formation is a desirable synthetic tool for industry and academia. Using commercially available substrates towards chemical transformations is often a strategy used to simplify the process of synthesizing compounds. This …
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High and low valent nickel complexes supported by tridentate and tetradentate ligands relevant for C–C bond formation reactions
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2023-12-01
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Catalytic enantioselective synthesis of oxindoles and benzofuranones bearing a quaternary stereocenter and reactions of palladium bisphosphine complexes relevant to catalytic C-C bond formation
In Part I the development of a new method for the construction of oxindoles and benzofuranones bearing quaternary stereocenters is discussed. A planar-chiral PPY derivative catalyzes the O-to-C acyl group migration (Black rearrangement) in a highly efficient and enantioselective manner. The utility …
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Carbon-Carbon Bonds Formed by Lewis Acid Catalysis or Photoactivation
Methods to generate C¬–C bonds are of great interest to synthetic organic chemists. Ideally, these reactions will be simple, robust, and catalytic. Herein is described the synthesis of tertiary and all-carbon quaternary centers from propargylic alcohols, organoboronates, and Lewis acids. Lewis …
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Carbon dots as sustainable photocatalysts for organic synthesis
… for a range of synthetically relevant transformations. This dissertation aims to establish CDs as versatile, sustainable photocatalysts for organic synthesis. Chapter 2 explores CDs as photocatalysts for net-oxidative and redox-neutral C-C bond formation. A variety of aromatic substrates and …
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Pd-katalysierte asymmetrische Synthese allylischer Sulfone und Stereochemie der Lithiumsalze chiraler allylischer Alpha-tert-Butylsulfonyl-Carbanionen
… by a hindered rotation around the alpha-C-S-bond and consequently configurative stability at appropriately low temperatures. Last-named renders the chiral anionic species capable for enantioselective C-C-bond formation with reactive electrophiles. The present work particularly deals with …
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Carbon-Carbon Bond Formation Via o-Lithiointermediates
The process of C-C bond formation via Directed ort/zo-Metalation (DoM) consists of two separate steps. Utilizing fractional equivalents of TMEDA in hydrocarbon solvents at 60°C, o-lithiation of anisole and dimethylaniline can be effected in >95% yields. The first step in the DoM process involves …
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I. Mechanistic significance of the Si-O-Pd linkage in the cross-coupling of organosilanolates; II. Applications of the water-gas shift reaction in organic synthesis
… (WGSR) in the catalysis of fundamental C-C bond forming reactions. To this end, three strategies were envisioned and investigated. In a first approach, the CO/H2O couple was exploited as the terminal reducing agent for a metal catalyst that is directly involved in the formation of a new C-C …
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Catalytic biomass conversion and upgrading into platform chemicals and liquid fuels
… intermediates, developing new strategies of C-C bond formation or chain extension is of particular interest. In this context, this study has discovered that N-heterocyclic carbenes (NHCs) are highly effective organic catalysts for HMF self-condensation to 5,5'-dihydroxymethylfuroin (DHMF), a new …
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Transmetalation from boronic esters to arylpalladium complexes without prior hydrolysis – mechanistic studies and preparative applications in the anhydrous, Suzuki-Miyaura cross-coupling reaction
The formation of C–C bonds is a foundational aspect of organic chemistry, and the development of transition-metal catalyzed, cross-coupling reactions has fundamentally changed the way chemists think about C–C bond formation. Within the class of transition-metal catalyzed, cross coupling reactions, …
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Nickel-catalyzed preparation of acrylamides from alpha olefins and isocyanates ; Synthetic studies toward ripostatin A
… amides arising from preferential C-C bond formation at the 2-position of the olefin. This sense of regioselectivity contrasts with the observed carboxamidation at the 1-position of the olefin when phosphine ligands are used. In this reaction, a simple alkene acts as the functional …
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Computational Studies of Selected Ruthenium Catalysis Reactions.
… of ruthenium and its effect on ruthenium-carbon bond strengths, carbon-hydrogen bond activation by 1,2-addition/reductive elimination pathways appropriate to catalytic hydrogen/deuterium exchange, and the possible intermediacy of highly coordinatively unsaturated (e.g., 14-electron) ruthenium …
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Mirroring Enzymes: The Role of H-Bonding In HQuin-BAM Catalyzed Asymmetric Aza-Henry Reactions: A DFT Study into the Reactivity, Mechanism, and Origins of Selectivity
… reactions such as Henry and aza-Henry transformations is important for developing and designing new synthetic organocatalysts. The focus of this dissertation will be on the use of density functional theory (DFT) for studying the asymmetric aza-Henry reaction. The first part of the thesis is …
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Traversing catalytic contexts for interrogation and design of carbon conversion electrocatalysts
… sites. We show how a new electrochemical C–C bond formation catalyst was developed by sequentially electrifying known hydroformylation catalysts. We show that electrification of a known organometallic catalyst leads to mechanistically distinct, voltage-driven reactivity. This work pioneers the …
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Asymmetrische Synthese ausgehend von allylischen Sulfoximinen: neuartige Gamma-Aminosäuren und cyclische Aminosulfoxonium Ylide
… construction of two stereo centers and a double bond, a highly diastereoselective aza-Michael-cyclisation and the creation of the acid moiety by oxidative degradation of a furan ring. The employed chiral auxiliary (S)-N,S-dimethyl-S-phenylsulfoximine could be recovered as a sulfinamide isolated …
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INTERACTION OF POLYCYCLIC AROMATIC HYDROCARBONS WITH DISSOLVED AND SEDIMENT ASSOCIATED HUMIC MATERIALS (NMR, FLUORESCENCE)
… materials. Three measures of the degree of C=C bond formation (UV absorptivity at 272 nm, atomic H/C ratio, and fraction of aromatic carbon determined by 13C NMR spectroscopy) indicated that pyrene is sorbed preferentially by humic acids possessing a high degree of aromaticity. Solution ionic …
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