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Hoskins, Travis Justin Christopher. "Carbon-carbon bond forming reactions." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29769.
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Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Dr. Christopher Jones; Committee Co-Chair: Dr. Pradeep Agrawal; Committee Member: Dr. Sujit Banerjee; Committee Member: Dr. Tom Fuller. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Buzzetti, Luca. "Photochemical Strategies for Carbon–Carbon Bond Forming Processes." Doctoral thesis, Universitat Rovira i Virgili, 2018. http://hdl.handle.net/10803/668971.
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La capacitat de generar intermedis radicalaris, sota condicions suaus, ha portat a l'emergent camp de la catàlisi fotoredox al desenvolupament de noves transformacions. Tradicionalment, aquesta es basa en l'ús d'un fotocatalitzador, que absorbeix eficientment llum i indueix una transferència simple d'electrons (SET). No obstant això, la reactivitat química de les molècules excitades electrònicament difereix fonamentalment de les que es troben en el seu estat fonamental. Una molècula en estat excitat és alhora una millor donant i acceptora d'electrons que en el seu estat fonamental i es comporta respectivament com una millor reductora i una millor oxidant.
El principal objectiu científic d'aquesta tesi doctoral ha estat investigar i comprendre la reactivitat de l'estat excitat d'algunes molècules orgàniques per desenvolupar nous processos fotoquímics de formació d'enllaços C-C. Per aconseguir aquest objectiu, s'ha combinat diferents eines de la química orgànica. En els primers projectes (discutits en els capítols III i IV), la fusió de la organocatàlisi i la fotoquímica han permès la funcionalització asimètrica directa en la posició β d’enals, desencadenada per l'excitació amb llum visible de sals de Imini quirals formades in situ.
A la segona part d'aquests estudis doctorals (discutit en el capítol V), s'ha explotat les propietats de l'estat excitat de 4-alquil-1,4-dihidropiridines (alquil-DHP) en combinació amb la catàlisi de metalls de transició pel desenvolupament de catalitzadors de níquel en reaccions radicalàries d'acoblament creuat.La capacidad de generar intermedios radicalarios, bajo condiciones suaves, ha llevado al emergente campo de la catálisis fotoredox al desarrollo de nuevas transformaciones. Tradicionalmente, esta se basa en el uso de un fotocatalizador, que absorbe eficientemente luz e induce una transferencia simple de electrones (SET). Sin embargo, la reactividad química de las moléculas excitadas electrónicamente difiere fundamentalmente de las que se encuentran en su estado fundamental. Una molécula en estado excitado es a la vez una mejor donante y aceptora de electrones que en su estado fundamental y se comporta respectivamente como una mejor reductora y una mejor oxidante. El principal objetivo científico de esta tesis doctoral ha sido investigar y comprender la reactividad del estado excitado de algunas moléculas orgánicas para desarrollar nuevos procesos fotoquímicos de formación de enlaces C-C. Para lograr este objetivo, se han combinado diferentes herramientas de la química orgánica. En los primeros proyectos (discutidos en los Capítulos III y IV), la fusión de la organocatálisis y la fotoquímica han permitido la funcionalización asimétrica directa en la posición β de enales, desencadenada por la excitación con luz visible de sales de iminio quirales formadas in situ. En la segunda parte de estos estudios doctorales (discutido en el Capítulo V), se ha explotado las propiedades del estado excitado de 4-alquil-1,4-dihidropiridinas (alquil-DHP) en combinación con la catálisis de metales de transición para el desarrollo de catalizadores de níquel en reacciones radicalarias de acoplamiento cruzado.
The emerging field of photoredox catalysis has led to the development of new transformations due to the ability to generate radical intermediates under mild conditions. Traditionally, this relies on the use of a photocatalyst, which efficiently absorbs light and induces a single electron transfer (SET). However, the chemical reactivity of electronically excited molecules differs fundamentally from that in the ground state. An excited-state molecule is both a better electron donor and a better electron acceptor than in the ground state and behaves respectively as a better reductant and a better oxidant. The main scientific objective of this doctoral research was to investigate and understand the excited-state reactivity of some organic molecules to develop novel photochemical C–C bond-forming processes. In order to achieve this goal, different tools of organic chemistry were combined. In the first projects (discussed in Chapter III and IV), the merger of organocatalysis and photochemistry enabled the direct asymmetric β-functionalization of enals triggered by the visible-light excitation of in situ formed chiral iminium salts. In the second part of the PhD studies (discussed in Chapter V), the excited-state properties of 4-alkyl-1,4-dihydropyridines (alkyl-DHP) were exploited in combination with transition metal catalysis for the development of nickel-catalyzed radical cross-couplings.
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Bentz, Emilie Louise Marie. "Zinc enolate coupling : carbon-carbon bond forming reactions." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419263.
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Mori-Quiroz, Luis Martin. "Transition metal catalyzed Carbon-nitrogen bond forming reactions." Revista de Química, 2015. http://repositorio.pucp.edu.pe/index/handle/123456789/101381.
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Las reacciones de formación de enlaces carbono-nitrógeno (C–N) son transformaciones fundamentales en la naturaleza y también procesos básicos para la preparación de moléculas y materiales relevantes a las actividades humanas. El desarrollo de reacciones nuevas y eficientes para la formación de enlaces C–N es, por lo tanto, de gran interés en los ámbitos académico e industrial. El progreso logrado en los últimos 20 años se ha enfocado, principalmente, en procesos de formación de enlaces Csp2–N; sin embargo, hay una creciente gama de reacciones catalizadas por metales de transición que permite la introducción de nitrógeno en estructuras alquílicas (formación de enlaces Csp3–N). Este artículo describe una selección de métodos catalíticos modernos para la formación de enlaces C–N.Carbon-nitrogen (C–N) bond forming reactions are fundamental transformations in nature and also basic processes for the preparation of molecules and materials relevant to human activities. The development of new and efficient reactions for the formation of C–N bonds are therefore of great interest in academic and industrial settings. Progress in the last 20 years has focused mainly in Csp2–N bond forming processes; however, there is growing range of transition metal catalyzed reactions for the introduction of nitrogen in alkyl frameworks (Csp3–N bond formation). This article describes a selection of modern catalytic methods for the formation of C–N bonds.
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Pilarski, Lukasz T. "Palladacycles for non-redox C-C bond forming reactions." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495644.
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This thesis is concerned with the use of palladacyclic complexes as catalysts for C-C and C-heteroatom bond-forming reactions in which an oxidation state change of the metal centre is not part of the catalytic cycle. To this end, the investigation of a range of known K²-C,L-based palladacycles in the allylation of aldehyde and imine substrates using stannanes, as well as the 1,4-conjugate arylation of enones and imines using arylboronic acids under mild conditions is described. In each case the commercially available phosphite-based dimeric palladacycle is found to be the most active complex capable of achieving excellent conversions (>90%) at the 0.5 - 2.5mol% loading range. Three previously unknown phosphinite and amidophosphinite palladium pincer complexes are also synthesised, characterised (including crystallographically) and tested in the 1,4-conjugate addition of phenylboronic acid to chalcone and found to be inactive.
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Hughes, Steven P. "Studies in bond-forming reactions of alpha-lithiated aziridines." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496916.
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Lomas, Sarah. "C-C bond forming catalysis with alkaline earth acetylides." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604644.
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After spending so many years in the shadow of magnesium chemistry the chemical abilities of the heavier alkaline earth metals, calcium, strontium and barium are beginning to emerge. This thesis is concerned with the development of a catalytic reactivity for the heavier alkaline earth metals. By taking inspiration from lanthanide metal catalysis, this thesis will begin by describing the hydroamination and hydrophosphination of unsaturated molecules catalysed by lanthanide and group 2 metals before extending this work to the group 2 catalysed hydroacetylation of terminal acetylenes (chapter 2), and the insertion of unsaturated bonds of carbodiimides (chapter 4), and organic isocyanates (chapter 5) into the polarised M-C bonds of group 2 acetylides. The third chapter of this thesis will describe the observation of the first acetylide coupling with a group 2 metal complex and extension of this reactivity to a catalytic process.
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Tundel, Rachel E. (Rachel Elizabeth). "Advances in palladium-catalyzed carbon-nitrogen bond forming processes." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36283.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2006.Vita. Leaf 68 blank.
Includes bibliographical references.
Chapter 1. Microwave-assisted, palladium-catalyzed C-N bond-forming reactions with aryl/heteroaryl nonaflates/halides and amines using the soluble amine bases DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) or MTBD (7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene) and a catalyst system consisting of Pd2dba3 and ligands (XantPhos, 2-dicylcohexylphosphino-2',4',6'-triisopropyl-1,1 '-biphenyl (XPhos) and 2-di-tert-butylphosphino-2',4',6'-triisopropyl-1, '-biphenyl) resulted in good to excellent yields of arylamines in short reaction times. Chapter 2. Using a catalyst comprised of the bulky, electron-rich monophosphine ligand di-tert-Butyl XPhos (2-di-tert-butylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl) and Pd2dba3 with sodium tert-butoxide as the base, amino heterocycles were coupled successfully with aryl/heteroaryl halides in moderate to excellent yields.
by Rachel E. Tundel.
S.B.
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Gates, Bradley Durward. "Novel thermal and electrochemical carbon-carbon bond-forming reactions /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487847761307998.
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Brace, Gareth Neil. "Applications of palladium-catalysed C-N bond forming reactions." Thesis, University of Bath, 2006. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428381.
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Bishop, Joshua Aaron. "Development and application of carbon-carbon bond forming methodologies." Thesis, Boston University, 2011. https://hdl.handle.net/2144/34459.
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Thesis (Ph.D.)--Boston UniversityPLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
The construction of novel small molecules is an invaluable tool to the fields of chemical biology and drug discovery. Information gained from introducing unique chemical moieties to biological systems allows for a better understanding of the governing dynamics of cellular mechanisms leading to new treatments for disease. The only way to explore uncharted biological space is by discovering and producing new chemical structures. The work described herein discusses the development and application of novel chemical methodologies to arrive at unique small molecules. An organocatalytic, asymmetric addition of carbon nucleophiles to prochiral aldimines was developed. This transformation capitalizes on the inherent properties of boron to promote a ligand exchange with chiral diols generating a chiral nucleophile in situ. Mechanistic studies were carried out to gamer a better understanding of this transformation. Propargyl, vinyl and aryl substituted amides are generated in high chemical yield and as single enantiomers. The transformation yields synthetically useful chiral building blocks as shown through the formal synthesis of the known pharmaceutical Xyzal©. Reaction discovery implementing a series of propargyl arnides lead to the development of unique Ag catalyzed 5-exo and 6-endo cyclizations to produce novel oxazolines and oxazines respectively. A novel, asymmetric formal [3+2] cycloaddition utilizing substituted isocyanoacetates as stabilized dipoles was invented. The transformation yields chemically unique nitrogen containing heterocycles with two stereogenic centers. The stereochemical outcome of the process is controlled through the choice of ligand to arrive at either the anti or syn dihydro-pynolidine product. The transformation represents the first reported application of a Ag/Trost ligand complex for a chemical process. As such, mechanistic investigations were canied out to illuminate the catalytic cycle. The synthesis and application of the first small molecule inhibitor of transcription factor LSF is discussed. The isoquinolinone scaffolds were modified from a medicinal chemistry standpoint to optimize the pharmacophore. Synthetic pathways, structure activity relationships and solubility characteristics of the isoquinolinones were addressed. A pharmacokinetic analysis was done to dete!Tlline a metabolic pathway and rate of metabolism of the lead compound in vitro. These unique small molecules are shown to have uM activity in vivo against human hepatocellular carcinoma cell lines with no signs of toxicity and uM activity in vitro against both 3T3 and HeLa cell lines.
2031-01-01
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Varma, Sreejith Jayasree. "Mimicking C-C bond forming reactions of core metabolism." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF038/document.
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Toutes les formes de vie assemblent et désassemblent continuellement des composés chimiques via un processus de consommation d'énergie appelé métabolisme. Le métabolisme est généralement modélisé en chimie et biologie par un cycle. Ce modèle dynamique traduit la transformation de composés de base en une cascade de produits appelés métabolites. Celui-ci est comparable à un ouragan à l’échelle moléculaire. De manière analogique et imagée un cyclone est constitué de deux éléments, l'air et l'eau, et transforme l’environnement qui l’entoure par un processus endothermique (consommateur d’énergie). Traditionnellement, la recherche chimique sur les origines de la vie est concentrée principalement sur la synthèse de composés chimiques sans suffisamment apprécier leur place dans la plus grande organisation biochimique de la vie. La vie construit toutes ses molécules à partir du dioxyde de carbone, pourtant elle manque étonnamment d'innovation à cet égard. Malgré presque 4 milliards d'années d'évolution, les organismes autotrophes utilisent seulement six voies différentes pour construire leurs molécules à partir du CO2. Parmi elles, deux voies – la voie de l’acétyle CoA (aussi appelée voie Wood-Ljungdahl) et le cycle du rTCA (également appelé le cycle de Krebs inverse) - sont considérées comme primitives, et contiennent les cinq molécules servant de précurseurs chimiques universels pour toute la biochimie. Comment et pourquoi les voies de l’acétyle CoA et du rTCA sont-elles apparues? Pour répondre à cette question, une recherche systématique a été effectuée afin de trouver des catalyseurs chimiques non-enzymatiques ou des minéraux simples, ainsi que des réactifs pouvant promouvoir les réactions d'anabolisme principal, particulièrement la voie de l’Acétyle CoA et le cycle de rTCA. A l’origine, pour créer les molécules organiques complexes comme les enzymes il a fallu que des molécules plus simples avec un moins grand nombre de carbone se forme sur terre et cela à partir du CO2. On peut donc supposer que les premiers produits à plusieurs carbones sont issus de synthèse totalement inorganique comme celles développer dans notre laboratoire, plutôt que d’une évolution chimique et organométallique simultanée, c’est-à-dire une interaction efficace entre une molécule carbonée et un ou plusieurs métaux à l’instar de certains enzymes. Après avoir trouvé autant de façons possible de promouvoir individuellement chaque étapes des cycles catalytiques étudiés, seules les conditions réactionnelles mutuellement compatibles (à savoir des conditions permettant de produire l’ensemble des métabolites dans le bon ordre) ont été retenuAll life forms continuously build up and break down its constituent chemical building blocks, through an energy consuming process called metabolism. Just like a hurricane’s dynamic patterns and its building blocks (air and water) as being equally fundamental to its nature, so too should metabolism’s dynamic chemical patterns and chemical building blocks be viewed as equally characteristic. Traditionally, much chemical research on the origins of life is overly focused on the synthesis of chemical building blocks without sufficiently appreciating their place in life’s larger biochemical self-organization. Life ultimately builds all of its molecules from carbon dioxide, yet it is surprisingly lacking in innovation in this respect. Despite nearly 4 billion years of evolution, autotrophic organisms use only six pathways to build their molecules from CO2. Two of these pathways – the acetyl CoA pathway (also known as the Wood-Ljungdahl pathway) and rTCA cycle (also known as the reverse Krebs cycle) - are thought to be ancestral, with just five molecules within them serving as the universal chemical precursors for all of biochemistry. How and why did these pathways get their start? To answer this question, a systematic search was designed to find simple, non-enzymatic chemical or mineral catalysts and reagents, that can promote the reactions of core anabolism, particularly the acetyl CoA pathway and the rTCA cycle. After finding as many ways as possible to promote each reaction, they could be narrowed down to mutually compatible conditions where many reactions can occur in sequence. The more of core anabolism that can be achieved under a single set of purely chemical conditions, the more likely it is to have constituted early prebiotic chemistry rather than a later product of chemical and biological evolution
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Gupta, Amit. "Novel Approaches to Fiber formation from Hydrogen Bond forming Polymers." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-08152008-135907/.
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Hydrogen bond forming polymers such as aliphatic polyamides and polyvinyl alcohol are important engineering plastics with good mechanical properties, high melting point and good chemical resistance. However, any further attempt at improving their mechanical properties gets thwarted due to the presence of intermolecular hydrogen bonding. Many approaches have been attempted in the past to suppress hydrogen bonding in aliphatic polyamides and have met with little or no success. These include, plasticizing the structure, dry spinning, wet spinning, gel spinning, and zone drawing/annealing. We have employed a new technique that involves the dry-jet wet spinning and drawing of GaCl3/nylon 66 complex. This new method allows traditional low draw ratios for nylon 66 to be increased by disrupting the interchain hydrogen bonded network. Fibers with a high modulus were obtained when high molecular weight nylon 66 was used. Further, we have also reviewed the concept of thermoreversible gelation and its application for gel spinning of ultra high molecular weight polyethylene fibers. We developed high strength and modulus nylon 6 and PVA fibers from the gels of these polymers in N-methyl pyrrolidinone. High molecular weight is essential for achieving more drawing of polymer chains which leads to high molecular orientation. Electrostatic spinning or electrospinning has received considerable research attention in recent years. It involves the application of an electric filed to a polymer solution or melt to facilitate production of fibers in the sub-micron down to nanometer range. We have investigated the complexation of GaCl3 with nylon 6 and developed porous nanofibers via the technique of electrospinning. Pores are generated by removal of salt from the as spun nanofibers via dipping in water. Researchers have tried in the past using a highly volatile solvent, or selective removal of one polymer from a bicomponent nanofiber for developing pores in nanofibers. However, using a metal salt proved to be a simple and fast approach for generating pores in electrospun nanofibers.
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Pawlikowski, Andrew V. "Developments in late metal-mediated C-N bond forming reactions /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8489.
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Miller, Oliver J. "Directed evolution of transketolase, a carbon-carbon bond-forming enzyme." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444878/.
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The enzyme transketolase (Enzyme Commission number: 2.2.1.1) has significant potential as a biocatalyst in the production of pharmaceuticals and fine chemicals. The enzyme catalyses the irreversible transfer of a C2 (1,2-dihydroxyethyl) moiety from p-hydroxypyruvate (P-HPA) to a wide range of acceptor substrates in a stereospecific reaction. However, commercial application of transketolase is currently restricted by the limited availability and expense of p-HPA. This project describes efforts to generate and identify variants of E. coli transketolase that are capable of accepting pyruvate: a related, but much cheaper compound. The variants were prepared by a novel directed evolution technique, "focused" error-prone PCR (fepPCR), and then screened for the desired activity: pyruvate (donor) and glycolaldehyde (acceptor) to (S)-3,4-dihydroxybutan-2-one (and carbon dioxide). The high-throughput screen consisted of the following steps: (1) transformation of a plasmid library into E. coli XLIO-Gold competent cells (2) culture of individual colonies in 384-well plates (3) lysis of the cultures (4) incubation of the lysates with cofactors and the target substrates and finally (5) high-throughput HPLC analysis measuring donor substrate (pyruvate) depletion. The first four steps were optimised to ensure the highest possible concentration of holotransketolase in each screening reaction. The HPLC method utilised a 50mm guard column as the separation matrix and was capable of processing one sample every 1.2 minutes. Several libraries of transketolase variants were generated using a novel mutagenesis technique: "focused" error-prone PCR (fepPCR). FepPCR uses knowledge of an enzyme as a map for targeting mutation to the most beneficial regions of the gene - in this case, three stretches of residues in the active site of E. coli transketolase (Ser24-His26, Gly99-Prol01, and Asp469- His473). Primers were designed to flank these small target sites (9-15bp) and they were PCR-amplified from the tkt gene under conditions that drastically lowered the fidelity of Taq DNA polymerase (0.14 misincorporations per nucleotide). The three mutated fepPCR products (50-54bp) were then cloned into the tkt vector pQR711 singly and in combination to create four distinct libraries. The PCR-based cloning techniques QuikChange Site-Directed Mutagenesis (Stratagene Ltd.) and QuikChange Multi Site-Directed Mutagenesis (Stratagene Ltd.) were both found to be effective for this step. The four libraries were screened for the target activity and the following levels of coverage were achieved: 100% of all possible single point mutations in the three targets sites and 22% of all possible combinations of double point mutations in the target sites. Careful analysis of the HPLC chromatograms failed to identify any variants with the desired activity. It is proposed that larger libraries may yield positive results.
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Tamuang, Suparb. "Mesoporous silica supported catalysts for carbon-carbon bond forming reactions." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3738/.
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The synthesis and characterisation of well-ordered mesoporous silicas, MCM-41, MCM-48, SBA-1, and SBA-2 has been carried out successfully. All of the synthesised materials possess the expected characteristic ordering as confirmed by powder X-ray diffraction. Moreover, surface modification of these mesoporous silicas had also been achieved through the incorporation of alkylamine groups and attachment of an asymmetric organometallic nickel-salen complex. The catalytic activity of the amino and nickel complex-modified mesoporous silica materials was examined for carbon-carbon bond forming reactions; Knoevenagel condensation of benzaldehyde and ethylcyanoacetate, and Kumada-Corriu coupling reaction between an organobromide and Grignard reagent, respectively. All the NH2-mesoporous silica catalysts result in high conversion (>95%) and can easily be reused by washing with water. Furthermore, the catalytic performances of the asymmetric nickel-salen complex bound to mesoporous silicas were found to be greater than 60% which is comparable to the homogenous nickel complex catalyst (62% conversion) but are more easily recycled. The further modification of catalysts to capture the remaining surface silanol groups in the modified-mesoporous silicas has been carried out by using chlorotrimethylsilane to obtain the surface functionalised with trimethyl groups instead of silanols. The methylated catalysts with MCM-41 and MCM-48 as support demonstrate better recyclability, while this was not observed in the cage-like SBA-1 and SBA-2 supports catalyst as the presence of additional trimethylsilyl groups could cause more pore blocking.
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Perry, Ian B. (Ian Brooks). "Transition metal-facilitated C-C and C-F bond forming." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112449.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Chemistry, 2017.Cataloged from PDF version of thesis. "June 2017."
Includes bibliographical references.
Chapter 1. Copper-Catalyzed Asymmetric Addition of Olefin-Derived Nucleophiles to Ketones A copper (I) catalyzed coupling olefins and ketones has been developed for the diastereo- and enantioselective generation of homopropargyl alcohols bearing vicinal stereocenters. This method allows for the generation of enantioenriched tertiary alcohols with a high degree of functional group compatibility. The utility of the process is further illustrated by a large scale synthesis with extremely low catalyst loading as well as the late stage modification of several pharmaceuticals. Chapter 2. Copper-Catalyzed Enantioselective Addition of Styrene-Derived Nucleophiles to Imines We describe the catalytic generation of amines bearing vicinal stereocenters with a moderate degree of diastereoselectivity. The stereoselective hydrocupration of an unactivated olefinic component is followed by nucleophilic addition of the organocuprate to an N-phosphinoyl protected imine. The mild and general process tolerates a broad-range of functionality, and the process was shown to be successful at a gram-scale synthesis. Chapter 3. Palladium-facilitated Regioselective Nucleophilic Fluorination of Aryl and Heteroaryl Halides. The preliminary findings regarding an aryl and heteroaryl halide fluorination process facilitated by palladium as a reagent is described. Stoichiometric studies illustrate the utility of the method in producing aryl fluorides with unprecedented regioselectivity, and preliminary studies into the fluorination of five- and six-membered heteroaryl bromides are described. Halogen atom substitution as a route to irreversible oxidative addition of aryl and heteroaryl halides is discussed. This strategy may serve to facilitate the fluorination of particularly problematic heteroaryl bromide and chloride substrates.
by Ian B. Perry.
S.B.
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Strieter, Eric R. "Mechanistic studies on metal-catalyzed carbon-nitrogen bond forming reactions." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32427.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005.Vita.
Includes bibliographical references.
Mechanistic studies on copper and palladium-catalyzed C-N bond forming reactions are described. To understand the mechanistic details of these processes, several principles of physical organic chemistry have been employed. Chapter 1. We have investigated the mechanism of the copper-catalyzed N-arylation of amides using aryl iodides, i.e., the Goldberg reaction. The focus of the work has been directed towards amides since this reaction remains the most versatile in the presence of Cu(I)/1,2- cliamine catalyst systems. The results provide insights into the role of 1,2-diamines in modulating the coordination environment around Cu(I). The catalyst is more efficient at high concentrations of 1,2-diamine and high concentrations of amide, as revealed by a nonlinear dependence of the rate on 1,2-diamine concentration. Extended premixing times between the Cu(I) precatalyst and the amide lead to an extensive induction period which can be attenuated by replacing the Cu(I) precatalyst with a Cu(II) precatalyst. Evidence for the reduction of the Cu(II) precatalyst through the oxidation of the amide is also presented. Furthermore, we demonstrate that a 1,2-diamine ligated Cu(I)-amidate may potentially serve as the reactive species that undergoes aryl halide activation. This was established through both its chemical and kinetic competency in the stoichiometric N-arylation process. This behavior has important consequences for new catalyst development since these results show the significance of both the diamine and amide in modulating the overall reactivity of the system. Chapter 2.
(cont.) A systematic mechanistic analysis of Pd(OAc)₂/ monophosphino- biaryl-catalyzed C-N bond forming reactions with aryl chlorides has been performed. The results provide insights into the relationship between the steady-state concentration of active Pd and the size and substitution pattern of the monophosphinobiaryl ligands. These insights into the nature of catalyst activation help highlight the importance of establishing a high concentration of active catalyst. The catalyst derived from the bulkiest ligand in the series, the tri-i-propyl ligand 13, exhibits both accelerated rate and the increased stability required for practical application of this reaction.
by Eric R. Strieter
Ph.D.
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Klingensmith, Liane M. (Liane May). "Mechanistic studies on palladium-catalyzed carbon-nitrogen bond forming reactions." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32489.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005.Vita.
Includes bibliographical references (leaves 68-69).
Precatalyst species present in a solution of Pd₂(dba)₃ and Xantphos were identified as Pd(Xantphos)(dba) and Pd(Xantphos)₂ by use of ³¹p NMR and independent syntheses. Pd(Xantphos)₂ was found to form at high ligand concentrations. To determine whether the formation of this species affected reaction rates, reaction calorimetry was used to explore the rate of the palladium-catalyzed coupling of 4-t-butylbromobenzene and morpholine using the ligand Xantphos at varying palladium to ligand ratios. It was found that catalyst activity is dramatically dependent on the concentration of ligand relative to palladium, due to formation of Pd(Xantphos)₂. Two plausible hypotheses for the low activity of Pd(Xantphos)₂ as a precatalyst are (1) a slow rate of dissociation of a ligand from the bis-ligated species, and (2) the high degree of insolubility of Pd(Xantphos)₂. Magnetization transfer experiments were used to probe the rate of dissociation of ligand for the bis-ligated species, and reaction calorimetry experiments were performed using the more soluble t-butylXantphos in comparison to Xantphos to determine whether the insolubility of' Pd(Xantphos)₂ causes it to have relatively low activity. It was found that solubility is not the main cause for the low activity of Pd(Xantphos)₂, and evidence was given to support the hypothesis that low activity results from the slow dissociation of a ligand from the bis-ligated species.
by Liane M. Klingensmith.
S.M.
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Miller, Karen M. (Karen Marie). "Selective, nickel-catalyzed carbon-carbon bond-forming reactions of alkynes." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32482.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005.Vita.
Includes bibliographical references.
Catalytic addition reactions to alkynes are among the most useful and efficient methods for preparing diverse types of substituted olefins. Controlling both regioselectivity and (EIZ)- selectivity in such transformations presents a significant challenge. In reactions that also involve the creation of a new stereocenter, the development of enantioselective processes is highly desirable. Several novel, nickel-catalyzed carbon-carbon bond-forming reactions of alkynes that display excellent regioselectivity and (E/Z)-selectivity are described. These reactions afford synthetically useful allylic and homoallylic alcohols, often with high enantioselectivity. A highly enantioselective method for the nickel-catalyzed reductive coupling of alkynes and aldehydes has been realized using the commercially available (+)- neomenthyldiphenylphosphine as a chiral ligand. Allylic alcohols are afforded with complete (E/Z)-selectivity, generally >95:5 regioselectivity, and in up to 96% ee. In conjuction with ozonolysis, this process is complementary to existing methods of enantioselective [alpha]-hydroxy ketone synthesis. In alkene-directed, nickel-catalyzed reductive couplings of 1,3-enynes with aldehydes and epoxides, the conjugated alkene dramatically enhances reactivity and uniformly directs regioselectivity, independent of the nature of the other alkyne substituent (aryl, alkyl (1°, 2°, 3°)) or the degree of alkene substitution (mono-, di-, tri-, and tetrasubstituted). The highly substituted 1,3-diene products are useful in organic synthesis and, in conjunction with a Rh-catalyzed, siteselective hydrogenation, afford allylic and homoallylic alcohols that previously could not be prepared in high regioselectivity (or at all) with related Ni-catalyzed alkyne coupling reactions. Enantiomerically enriched terminal epoxides can be employed to afford enantiomerically enriched homoallylic alcohols. P-chiral, monodentate ferrocenyl phosphine ligands are efficient promoters of catalytic, asymmetric reductive coupling reactions of 1,3-enynes with aromatic aldehydes and with ketones. The latter represents the first catalytic intermolecular reductive coupling of alkynes and ketones, asymmetric or otherwise, to be reported. Both of these methods afford chiral 1,3-dienes in excellent regioselectivity and modest enantioselectivity. Nickel-catalyzed reductive couplings of 1,6-enynes and aldehydes also display very high (>95 : 5) regioselectivity. Use of a monodentate phosphine as an additive leads to formation of the opposite regioisomer in equal and opposite selectivity (5: >95). These results provide strong evidence for an interaction between the remote alkene and the metal center during the regioselectivity-determining step.
by Karen M. Miller..
Ph.D.
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Eno, Meredith Suzanne. "Development of Metal-Catalyzed Asymmetric Carbon-Carbon Bond Forming Reactions." Thesis, Boston College, 2017. http://hdl.handle.net/2345/bc-ir:107422.
Full textAbstract:
Thesis advisor: James P. MorkenThis dissertation describes the development of four metal-catalyzed carbon-carbon bond forming methods. The first project presented is a palladium-catalyzed proparyl-allyl cross-coupling which proceeds via a kinetic resolution to give enantioenriched 1,5-enynes. Next the asymmetric rhodium-catalyzed hydroformylation of 1-alkenes is described. This reaction delivers synthetically useful a-chiral aldehydes in up to 98:2 er and up to 15:1 branched to linear ratio. The development of a unique nickelcatalyzed asymmetric Kumada coupling of cyclic sulfates is presented. Mechanistic studies reveal the reaction proceeds via an SN2 oxidative addition of a chiral nickelcomplex. Finally, a-Substituted allyl bis(boronic) esters, which are derived from 1,2-diboration of 1,3-dienes are shown to undergo allylation and subsequent Suzuki coupling with aldehydes tethered to sp2 electrophiles. The carbocycle products obtained bear three contiguous stereocenters and were used as intermediates in the synthesis of complex molecules
Thesis (PhD) — Boston College, 2017
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Aelvoet, Karel. "Research of bifunctional catalysts for C-C bond forming reactions." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2379/.
Full textAbstract:
Bifunctional catalysis is a well understood phenomenon in nature, with enzymes frequently using two (or more) functional groups to accomplish selective transformations on a suitable substrate. It is becoming clear however, that bifunctional catalysis is not merely of interest to explain or mimic biological efficiency and rate enhancement, but is a viable design principle for the development of new molecular catalysts. In this thesis we have prepared achiral amino-boronic acid compounds with different scaffold structures based on general structures 1 and 2.(^5). although these compounds did not show any reactivity towards the MBH and aza-MBH reaction, they were very successful as catalysts for the aldol reaction. For this reaction it was possible to select the wanted product (aldol or chalcone product) using the same bifunctional catalyst only by changing the solvent. Also with hydroxyacetone some excellent results were gained with yields between 49 to 97% for both aromatic and aliphatic aldehydes in very high regioselectivity.
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Wainwright, Matthew. "P-N bond forming reactions for the synthesis of phosphines." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/33822.
Full textAbstract:
The reactions of dialkylureas and thioureas with chlorodiphenylphosphine yielded ligands of the type {Ph2PN(R)}2C=E, where R = Me or Et and E = O or S. Reaction of the ligands {Ph2PN(Me)}2C=O and {Ph2PN(Et)}2C=O with Pt(II), Pd(II) and Mo(0) resulted in the formation of square planar and octahedral chelate complexes, while {Ph2PN(Et)}2C=O also acted as a bridging ligand when reacted with Au(I). The coordination chemistry of {Ph2PN(Me)}2C=S was less predictable and reaction of the ligand with Pd(II) resulted in P–N bond cleavage and the formation of a five-membered heterocycle.
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Das, Sajal. "Investigations on synthetic organic transformations : application to C-C and C-N bond forming processes." Thesis, University of North Bengal, 2007. http://hdl.handle.net/123456789/1146.
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Mudarra, Alonso Ángel Luis. "Coinage complexes in C-C and C-N bond-forming reactions." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/670357.
Full textAbstract:
Els complexos organometàl·lics de coure, plata i or juguen un paper fonamental com espècies reactives
en diverses transformacions químiques. Aquesta tesi aporta coneixement sobre el comportament
d’aquests complexos en la formació d’enllaços C-C i/o C-N. En concret, estudiem: i) el mecanisme de
reacció a través del qual els complexos de coure co-catalitzen un acoblament oxidant en el context de
sistemes bimetàl·lics de rodi i coure; ii) el potencial de nucleòfils de plata com a agents transmetal·lants
en reaccions de trifluorometilació catalitzades per pal·ladi; iii) el mecanisme de reacció de sistemes
bimetàl·lics de Pd/Ag emprant un sistema model; i iv) el comportament de complexos bis(trifluorometil)
cuprat, argentat i aurat com a nucleòfils. En aquesta tesi, on s´han combinat estudis experimentals i
computacionals, s’ha adquirit nou coneixement sobre els processos estudiats, i s’ha contribuït al camp de
la recerca química basada en el coneixement.Los complejos organometálicos de cobre, plata y oro juegan un papel fundamental como especies reactivas en diversas transformaciones químicas. Esta tesis aporta conocimiento sobre el comportamiento de estos complejos en la formación de enlaces C-C y/o C-N. En concreto, estudiamos: i) el mecanismo de reacción por el cual complejos de cobre co-catalizan un acoplamiento oxidante en el contexto de sistemas bimetálicos de rodio y cobre; ii) el potencial de nucleófilos de plata como agentes transmetalantes en reacciones de trifluorometilación catalizadas por paladio; iii) el mecanismo de reacción de sistemas bimetálicos de Pd/Ag usando un sistema modelo; y iv) el comportamiento de complejos bis(trifluorometil) cuprato, argentato y aurato como nucleófilos. En esta tesis, donde se han combinado estudios experimentales y computacionales, se ha adquirido nuevo conocimiento sobre los procesos estudiados, y se ha contribuido al campo de la investigación química basada en el conocimiento.
Organometallic coinage metal complexes are be key reactive species for promoting a wide variety of chemical transformations. This thesis improves the understanding the behavior of these complexes in relevant C-C and/or C-N bond-forming reactions. Specifically, we have explored: i) the mechanistic intricacies of copper species as co-catalyst in the context of rhodium/copper-catalyzed oxidative coupling reactions; ii) the capability of silver nucleophiles as transmetalating agents in palladium-catalyzed trifluoromethylation reactions; iii) the reaction mechanism of Pd/Ag bimetallic reactions using a model system as probe; and, iv) the study of bis(trifluoromethyl) coinage metallates as nucleophiles. The fundamental insights gathered in this Thesis, encompassing both experimental and computational approaches, improve our understanding of the processes under study and make a contribution to the general field of knowledge-driven research in Chemistry.
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Fossey, John Stephen. "Group 10 NCN pincer complexes for C-C bond forming catalysis." Thesis, Queen Mary, University of London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409665.
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Kanuru, Vijaykumar. "Understanding surface mediated C-C and C-N bond forming reactions." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608956.
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Wagaw, Seble-Hiwot Teshome 1971. "Development and application of palladium-catalyzed carbon-nitrogen bond forming reactions." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9522.
Full textAbstract:
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1999.Includes bibliographical references.
Chapter 1. Pd-Catalyzed Cross-Coupling of a-Substituted Optically Active Amines with Aryl Bromides. The palladium-catalyzed coupling reaction of enantiomerically enriched a-substituted amines with aryl bromides is described. The choice of ligand in the palladium-catalyzed coupling reaction is critical to the formation of chiral aniline products without erosion of optical purity. While Pd/P(otolyl) 3 successfully catalyzes the intramolecular aryl amination of optically active asubstituted amines, intermolecular coupling reactions with this catalyst system gives racemized products. In contrast, the corresponding intermolecular coupling reaction of optically active amines with aryl bromides employing Pd/bis(phosphine) catalysts gives products with no decrease in enantiomeric excess. The development of the Pd/Bl NAP-catalyst (BINAP = 2,2'-bis(diphenylphosphino)-1, 1 '-binaphthyl) for the coupling reaction of amines with aryl bromides is described. The use of this catalyst system provides coupled products in significantly improved yields when primary amine substrates are utilized, as well as preventing racemization of chiral substrates. A mechanism for the observed racemization with the Pd/P( o-tolyl)3 catalyst is proposed. A discussion on the difference in reactivity between Pd/P( o-tolyl)3 and Pd/bis(phosphine) catalysts is presented. The utility of this methodology is demonstrated in the synthesis of ( S)-2-methylcarboxylate-N-acetylindoline, which is a key intermediate in the synthesis of a potent ACE inhibitor. Chapter 2. Pd-Catalyzed Amination of Halog enated Heterocycles. Aminopyridines are efficiently synthesized under mild conditions by the cross coupling reaction of 2-, 3-, and 4-bromopyridines, and 2-chloropyridines with primary and secondary amines utilizing Pd/bis(phosphine)-catalysts A variety of aminopyridines were prepared including mono-, di-, tri-, and tetrapyridylamine products. Application of this reaction to the amination of various nitrogen containing halogenated heterocycles is discussed. Chapter 3. A Palladium-Catalyzed Method for the Preparation of lndoles via the Fischer lndole Synthesis. A Pd-catalyzed method for the preparation of N-aryl benzophenone hydrazones is described. The use of 1-2.5 mol % of a Pd/BINAP based catalyst provides N-aryl benzophenone hydrazones in good yields. Using a Pd/9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (Xantphos) catalyst the desired hydrazones are produced in excellent yields and at 0.1 mol % of catalyst. The N-aryl benzophenone hydrazones are converted to indole products via an in situ hydrolysis/Fischer cyclization protocol. A procedure that extends this methodology to the synthesis of N-alkyl indoles via the intermediacy of N-aryl-N-alkyl benzophenone hydrazones is described. Similarly, the Pd-catalyzed preparation of diaryl benzophenone hydrazones, followed by the hydrolysis/Fischer cyclization protocol affords N-aryl indole products in good yields.
by Seble-Hiwot Teshome Wagaw.
Ph.D.
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Rathod, J. B. "Synthetic explorations into carbon-carbon and carbon-nitrogen bond forming reactions." Thesis(Ph.D.), CSIR National Chemical Laboratory, 2019. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5187.
Full textAbstract:
The thesis mainly deals with the explorations of homogeneous palladium and heterogeneous Ruthenium catalyzed Carbon–Nitrogen bond forming reaction of aryl halide with amine and alkyne with sodium azide and benzyl bromide. Heterogeneous palladium, Gold and Brønsted acid catalysed C-C bond forming reaction is investigated by using cross coupling and Michael addition reaction of p-Quinone methide with nucleophile. The work demonstrated in this thesis has been divided into three chaptersCSIR HRDG for fellowship
AcSIR
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Mandal, S. K. "Selectivity in C-C bond forming reactions on arene-tricarbonylchromium template." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1999. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2947.
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Jha, Satadru. "Organic reactions methodology : studies on carbon-nitrogen hetero bond forming reactions." Thesis, University of North Bengal, 2004. http://hdl.handle.net/123456789/745.
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Arvanitis, Elena-Alexia. "Sulfone mediated synthesis of heterocycles on solid support." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321910.
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Alandini, Nurtalya. "1,4-Dihydropyridines as Versatile Reagents in Photochemical Carbon-Carbon Bond-Forming Processes." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/669606.
Full textAbstract:
Les transformacions fotoquímiques es basen en la capacitat de molècules o catalitzadors orgànics d’absorbir llum i arribar als estats electrònicament excitats. Atès que les propietats físiques i químiques de les molècules en estat excitat difereixen significativament de l'estat fonamental, la química intervinguda per la llum pot oferir nous patrons interessants de reactivitat que no estan disponibles amb l'activació tèrmica.
L’objectiu principal d’aquests estudis de doctorat va ser implementar estratègies fotoquímiques adequades per desenvolupar transformacions sintètiques útils no assolibles mitjançant processos tèrmics ja coneguts. En particular, he pogut investigar i explotar la capacitat única de les 4-substit-1,4-dihidropiridines (DHPs) per formar radicals de carboni centrats en condicions suaus. En el primer projecte (capítol III), es van utilitzar 4-alquil-1,4-dihidropiridines (alquil-DHPs) com a precursors del radical alquil en l'alquilació enantioselectiva d’enals desencadenada per l'excitació amb llum visible de sals d’iminium quirals generades in situ.
En la segona part d’aquests estudis de doctorat (analitzats al capítol IV), es van emprar 4-carbamoil-1,4-dihidropiridines (carbamoil-DHP) com a font de radicals de carbamoil i es van aplicar en reaccions d’acoblament creuat de radicals catalitzats amb níquel per a la síntesi d’una àmplia gamma de (hetero) aril amides.Las reacciones fotoquímicas se basan en la capacidad de moléculas orgánicas o catalizadores para absorber luz y alcanzar a un estado electrónicamente excitado. Dado que tanto las propiedades químicas como físicas de las moléculas en su estado excitado se diferencian de aquellas en su estado fundamental, la fotoquímica puede ofrecer acceso a interesante nueva reactividad no disponible por la vía térmica. El principal objetivo de esta tesis doctoral fue la implementación de estrategias fotoquímicas para el desarrollo de reacciones sintéticamente útiles no accesibles mediante el empleo de métodos térmicos ya establecidos. En particular, la investigación y explotación de la capacidad única de las 1,4-dihidropiridinas-4-substituidas (DHPs) para formar radicales de tipo carbono usando condiciones suaves. En el primer proyecto, 1,4-dihidropiridinas-4-alquilo (DHP-alquilo) se emplearon como precursores de radicales para la alquilación enantioselectiva de enales desencadenada por excitación mediante luz visible de una sal de iminio quiral formada in situ. En la segunda parte de la tesis doctoral (desarrollada en el capítulo 4), 1,4-dihidropiridinas-4-carbamoil (DHP-carbamoil) fueron empleadas como fuente de radicales de tipo carbamoil y aplicadas en reacciones de acoplamiento de radicales catalizadas por niquel para la síntesis de un amplio rango de (hetero)aril amidas.
Photochemical transformations rely on the ability of organic molecules or catalysts to absorb light and reach the electronically excited states. Since the chemical and physical properties of excited-state molecules significantly differ from the ground state, light-mediated chemistry can offer interesting new reactivity patterns that are unavailable under thermal activation. The main objective of this doctoral studies was to implement photochemical strategies suitable for developing useful synthetic transformations not achievable using established thermal approaches. In particular, I investigated and exploited the unique ability of 4-substituted-1,4-dihydropyridines (DHPs) to form carbon-centered radicals under mild conditions. In the first project (Chapter III), 4-alkyl-1,4-dihydropyridines (alkyl-DHPs) were employed as alkyl radical precursors in the enantioselective alkylation of enals triggered by the visible-light excitation of in situ generated chiral iminium salts. In the second part of the doctoral studies (discussed in Chapter IV), 4-carbamoyl-1,4-dihydropyridines (carbamoyl-DHP) were employed as carbamoyl radical sources and applied in nickel-catalyzed radical cross-coupling reactions for the synthesis of a wide range of (hetero)aryl amides.
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Frost, Robert Mark. "Carbon-carbon bond forming reactions towards the synthesis of liquid crystal molecules." Thesis, University of Exeter, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436309.
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Wilkinson, Matthew. "Bulky arylphosphines and arylarsines for catalysis of C-C bond-forming reactions." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274605.
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Nogi, Keisuke. "Nickel- and Cobalt-Catalyzed Carbon-Carbon Bond-Forming Reactions Employing Carbon Dioxide." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215559.
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Oe, Toshiyuki. "Studies on Atom Efficient C-C Bond Forming Reactions Using Organoheteroatom Compounds." 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/149810.
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Wolfe, John P. (John Perry) 1970. "Late transition metal catalyzed C-N and C-C bond forming reactions." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9521.
Full textAbstract:
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1999.Includes bibliographical references.
New methods for the palladium-catalyzed amination of aryl halides are described. Key to these is the development of new catalysts and reaction conditions for these transformations. Initially, P(o-tol)3 ligated palladium catalysts were investigated but gave way to systems that used chelating phosphine ligands which substantially expanded the scope of the catalytic amination methodology. Palladium catalyst systems based on BINAP ((2,2'-diphenylphosphino)-1, 1 '-binaphthyl) allowed for the transformation of a much wider range of amines and aryl halide substrates, as well as aryl triflates. Of practical significance was that the use of cesium carbonate as a base at 100 °C substantially increased the functional group tolerance of the method. Palladium catalysts supported by novel, bulky, electron-rich phosphine ligands are exceptionally effective in the C-N, C-0, and C-C coupling procedures. For some substrate combinations, these palladium catalysts are effective for the room-temperature catalytic amination of aryl chlorides. These palladium catalysts are also highly effective for Suzuki coupling reactions of aryl bromides and chlorides at room temperature. Suzuki coupling reactions of aryl bromides and aryl chlorides are effective at very low catalyst loadings (0.000001-0.005 mol % Pd for ArBr, 0.02-0.05 mol % for ArCI) at 100 °C, and reactions of hindered aryl halides or boronic acids are effected at moderate catalyst loadings (1 mol % Pd). The high reactivity of these catalysts towards aryl chlorides challenges the conventional dogma that chloride substrates cannot be transformed under mild conditions with palladium catalysts, and significantly expands the pool of substrates available for cross-coupling chemistry.
by John P. Wolfe.
Ph.D.
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Cibuzar, Michael. "Metal Catalyzed Group 14 And 15 Bond Forming Reactions: Heterodehydrocoupling And Hydrophosphination." ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1023.
Full textAbstract:
Investigation of catalytic main-group bond forming reactions is the basis of this dissertation. Coupling of group 14 and 15 elements by several different methods has been achieved. The influence of Si–N heterodehydrocoupling on the promotion of α-silylene elimination was realized. Efficient Si–N heterodehydrocoupling by a simple, earth abundant lanthanide catalyst was demonstrated. Significant advances in hydrophosphination by commercially available catalysts was achieved by photo-activation of a precious metal catalyst.
Exploration of (N3N)ZrNMe2 (N3N = N(CH2CH2NSiMe3)33–) as a catalyst for the cross-dehydrocoupling or heterodehydrocoupling of silanes and amines suggested silylene reactivity. Further studies of the catalysis and stoichiometric modeling reactions hint at α-silylene elimination as the pivotal mechanistic step, which expands the 3p elements known to engage in this catalysis and provides a new strategy for the catalytic generation of low-valent fragments. In addition, silane dehydrocoupling by group 1 and 2 metal bis(trimethylsilyl)amide complexes was investigated. Catalytic silane redistribution was observed, which was previously unknown for d0 metal catalysts.
La[N(SiMe3)2]3THF2 is an effective pre-catalyst for the heterodehydrocoupling of silanes and amines. Coupling of primary and secondary amines with aryl silanes was achieved with a loading of 0.8 mol % of La[N(SiMe3)2]3THF2. With primary amines, generation of tertiary and sometimes quaternary silamines was facile, often requiring only a few hours to reach completion, including new silamines Ph3Si(nPrNH) and Ph3Si(iPrNH). Secondary amines were also available for heterodehydrocoupling, though they generally required longer reaction times and, in some instances, higher reaction temperatures. By utilizing a diamine, dehydropolymerization was achieved. The resulting polymer was studied by MS and TGA. This work expands upon the utility of f-block complexes in heterodehydrocoupling catalysis.
Stoichiometric and catalytic P–E bond forming reactions were explored with ruthenium complexes. Hydrophosphination of primary phosphines and activated alkenes was achieved with 0.1 mol % bis(cyclopentadienylruthenium dicarbonyl) dimer, [CpRu(CO)2]2. Photo-activation of [CpRu(CO)2]2 was achieved with a commercially available UV-A 9W lamp. Preliminary results indicate that secondary phosphines as well as internal alkynes may be viable substrates with this catalyst. Attempts to synthesize ruthenium phosphinidene complexes for stoichiometric P–E formation have been met with synthetic challenges. Ongoing efforts to synthesize a ruthenium phosphinidene are discussed.
The work in this dissertation has expanded the utility of metal-catalyzed main-group bond forming reactions. A potential avenue for catalytic generation low-valent silicon fragments has been discovered. Rapid Si–N heterodehydrocoupling by an easily obtained catalyst has been demonstrated. Hydrophosphination with primary phosphines has been achieved with a commercially available photocatalyst catalyst, requiring only low intensity UV light.
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Bennur, T. H. "Selective oxidations and carbon-carbon bond forming reactions using transition metal catalysts." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2003. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2541.
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Coll, Serrahima Mª Mercè. "Sugar-based ligand libraries for asymmetric reductions and c-c bond forming reactions." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/65638.
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Un dels principals mètodes per a sintetitzar productes enantiomericament purs és la catàlisi asimètrica utilitzant compostos organometàl•lics quirals. En aquesta estrategia, el disseny i preparació de lligands quirals és molt important. En aquest context, nosaltres hem desenvolupat nous lligands quirals per diverses reaccions de catàlisi asimètrica.
Concretament ens hem centrat en:
(a) L’aplicació d’una llibreria de lligands fosfit-fosforoamidit i difosforoamidit derivats de carbohidrats en la hidrogenació de olefines proquirals. Aquests lligands han donat excel•lents enantioselectivitats (up to >99% ee).
(b) L’aplicació de les llibreries de lligands tioèter-fosfit, tioèter-fosfinit i tioèter-fosforoamidit derivats de carbohydrats en la hidrogenació catalitzada per iridi de olefins no funcionalitzades i en reaccions de substitució al•lílica catalitzada per paladi. Els resultats obtinguts en hidrogenació competeixen favorablement amb els millors resultats publicats prèviament.
(c) L’aplicació de llibreries de lligands pseudo-dipèptids i tioamides derivats de carbohidrats en transferència d’hidrogen de cetones. Els resultats obtinguts, novament competeixen favorablement amb els publicats anteriorment obtenint excel•lents enantioselectivitats (up to 99%) per un ampli rang de substrats.One of the main methods for producing enantiomerically pure compounds is metal asymmetric catalysis. An important step in this strategy is the design and preparation of chiral ligands. In this context, we have developed new chiral ligands for several important asymmetric catalytic reactions. Specifically we have focused on: (a) The application of a furanoside phosphite-phosphoroamidite and diphosphoroamidite ligand library in the hydrogenation of prochiral olefins. These ligands have provided excellent enantioselectivities (up to >99% ee). (b) The application of furanoside thioether-phosphite, thioether-phosphinite and thioether-phosphoroamidite ligand libraries in the challenging Ir-catalyzed hydrogenation of unfunctionalized olefins and in Pd-allylic substitution reactions. The results in hydrogenation compete favourable with the best ones previously reported. (c) The application of carbohydrate-based pseudo-dipeptide and thioamide ligand libraries in transfer hydrogenation of ketones. The results again compete favourable with the best one previously reported. Unprecedent enzyme-like behaviour has been obtained, providing ee’s up to 99% for a wide range of substrates.
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Casi, Giulio. "Peptide bond forming reactions : from methodology to the construction of a semisynthetic enzyme /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17598.
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Masuda, Yuusuke. "Development of New C-C Bond Forming Reactions Utilizing Light as Energy Source." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225634.
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Fava, Eleonora [Verfasser]. "Visible light mediated photoredox catalysis: reductive carbon-carbon bond forming reactions / Eleonora Fava." München : Verlag Dr. Hut, 2015. http://d-nb.info/1079768645/34.
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Graham, Alan. "New C-C and C-N bond forming reactions mediated by chromium complexation." Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760696.
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Maluenda, Borderas Irene. "(N-heterocyclic carbene) : metal catalysed carbon-carbon and carbon-heteroatom bond-forming reactions." Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/76274/.
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Senecal, Todd D. (Todd Dale). "Carbon-trifluoromethyl bond forming reactions and palladium-catalyzed cyanation of (hetero)aryl halides." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82321.
Full textAbstract:
Thesis (Ph. D. in Organic Chemistry)--Massachusetts Institute of Technology, Dept. of Chemistry, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references.
Chapter 1 Nucleophilic trifluoromethyl sources were systematically examined in stoichiometric palladium experiments to determine the most efficient class of reagents for transmetallation. In conjunction with reductive elimination studies, this led to the development of the first system for the trifluoromethylation of aryl chlorides. Chapter 2 A method for the oxidative trifluoromethylation of (hetero)aryl boronic acids is reported. Bench top setup and visual reaction monitoring makes this process particularly well suited to medicinal and academic chemists. Fast reaction times allow for the trifluoromethylation of heterocyclic boronic acids that are prone to facile protodeboronation. Chapter 3 A trifluoromethylation of potassium vinyl trifluoroborates via iron catalysis has been developed. Excellent E:Z ratios are observed for styryl trifluoroborates. Initial investigations suggest a mechanistic pathway that diverges from our previous (hetero)aryl trifluoromethylation systems. Chapter 4 A highly efficient system for the palladium-catalyzed cyanation of (hetero)aryl halides is disclosed. By employing palladacycle precatalysts, cyanide binding during catalyst formation is minimized, allowing for low catalyst loadings even with unactivated aryl chlorides. The method utilizes a non-toxic cyanide source and exhibits excellent functional group tolerance, particularly of free N-H groups and typically challenging five membered heterocycles.
by Todd D. Senecal.
Ph.D.in Organic Chemistry
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Billingsley, Kelvin L. "Recent advances in palladium-catalyzed carbon-carbon and carbon-boron bond forming processes." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43777.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2008.Vita.
Includes bibliographical references.
Chapter 1. Highly active and efficient catalyst systems derived from palladium precatalysts and monophosphine ligands for the Suzuki-Miyaura cross-coupling reaction of heteroaryl boronic acids and esters has been developed. This method allows for the preparation of a wide variety of heterobiaryls in good to excellent yields and displays a high level of activity for the coupling of heteroaryl chlorides as well as hindered aryl and heteroaryl halides. Specific factors that govern the efficacy of the transformation for certain heterocyclic motifs were also investigated. Chapter 2. A highly efficient method for the palladium-catalyzed Suzuki-Miyaura reaction of lithium triisopropyl 2-pyridylborates has been developed. Catalysts comprised of Pd2dba3 and either diaryl or dialkyl phosphine oxide supporting ligands were found to be ideal for the transformation. This report represents one of the most general systems for the cross-coupling of aryl and heteroaryl bromides and chlorides with 2-pyridyl-derived nucleophiles. Chapter 3. Catalysts comprised of Pd and dialkylmonophosphinobiaryl ligands provide highly active systems for the borylation of aryl and heteroaryl chlorides. The direct preparation of symmetrical and unsymmetrical biaryls from two aryl chlorides without the need to isolate the intermediate boronate esters is also described. Additionally, computational studies provide insight into the roles of the biaryl phosphine ligand as well as KOAc in the catalytic cycle. Chapter 4. A highly efficient method for the palladium-catalyzed borylation of aryl halides with an inexpensive and atom-economical boron source, pinacol borane, has been developed.
(cont.) This system allows for the conversion of aryl and heteroaryl iodides, bromides and several chlorides, containing a variety of functional groups, to the corresponding pinacol boronate esters. In addition to the increase in substrate scope, this is the first general method where relatively low quantities of catalyst and short reaction times can be employed.
by Kelvin L. Billingsley.
Ph.D.
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Ishida, Naoki. "Development of New Carbon-Carbon Bond Forming Reactions Catalyzed by palladium and Nickel." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/57281.
Full textAbstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(工学)
甲第13848号
工博第2952号
新制||工||1436(附属図書館)
26064
UT51-2008-C764
京都大学大学院工学研究科合成・生物化学専攻
(主査)教授 村上 正浩, 教授 大嶌 幸一郎, 教授 杉野目 道紀
学位規則第4条第1項該当
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Seely, Franklin Lee. "Bis(trimethylstannyl)benzopinacolate Promoted Radical Carbon-Carbon Bond Forming Reactions and Related Studies." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1290711413.
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