Siga este enlace para ver otros tipos de publicaciones sobre el tema: H₂ activation.
Tesis sobre el tema "H₂ activation"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores tesis para su investigación sobre el tema "H₂ activation".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore tesis sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Weeks, Amanda. "C-H activation in organic synthesis". Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535205.
Texto completo
2
Doyle, Claire Marie. "C-H activation reactions of tetrahydropyridines". Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9469.
Texto completoResumen
This thesis is presented as five chapters: Chapter 1.0 is divided into two sections: the first is a review of palladium-catalysed C–C bond forming reactions. It covers palladium-catalysed cross-coupling reactions; C–H bond functionalisation; the Heck reaction and functionalisation of heteroaromatic C–H bonds. Secondly the use of tetrahydropyridines in organic synthesis is discussed, with a particular focus on methodology developed by the Craig group. Chapter 2.0 discusses the research carried out during this studentship. It is divided into six sections and discusses the results obtained from research efforts into: our initial strategy for tetrahydropyridine synthesis; an SN1 approach; an α,β-unsaturated lactam approach; synthesis of 3-methoxy aryl-substituted tetrahydropyridines; synthesis of heteroaromatic analogues and further elaboration of tricyclic tetrahydropyridines. Chapter 3.0 details future work proposed within the areas described above. Chapter 4.0 details the experimental procedures employed and spectroscopic data for the compounds discussed in chapter 2.0. Finally, chapter 5.0 lists the references sourced in this thesis.
3
Di, Matteo Marco. "Selective C-H Activation of Terpenes". Electronic Thesis or Diss., Sorbonne université, 2024. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2024SORUS001.pdf.
Texto completoResumen
Ce travail de thèse porte sur la découverte de nouvelles stratégies pour l'activation/fonctionnalisation C-H des terpènes, avec un accent particulier sur le (+)-limonène et la catalyse au palladium. Tout d'abord, nous avons décrit le couplage C(sp2)-H/C(sp2)-H déshydrogénant catalysé par le Pd(II) entre le limonène et des alcènes pauvres en électrons, avec une extension à divers terpènes et terpénoïdes. Ensuite, nous avons étudié la post-fonctionnalisation d'un produit issu du couplage déshydrogénant développé et de l'éthynylbenzène en conditions micellaires. Par la suite, nous avons développé avec succès le couplage redox neutre C(sp2)-H/C(sp2)-X entre le (+)-limonène et des bromoalcènes. Cette stratégie, qui est complémentaire par rapport au couplage déshydrogénant, nécessite une charge plus faible du catalyseur au palladium et du sel d'argent par rapport au couplage étudié précédemment. Enfin, nous avons étudié de nouvelles approches pour la synthèse du cannabidiol (CBD). Des travaux futurs seront nécessaires pour évaluer les stratégies et atteindre la cible synthétiqueThis thesis work is dealing with the discovery of new strategies for the C-H activation/functionalization of terpenes, with particular emphasis on (+)-limonene and palladium catalysis. Firstly, we described the dehydrogenative Pd(II)-catalyzed C(sp2)-H/C(sp2)-H coupling between limonene and electron-poor alkenes, with extension to various terpenes and terpenoids. Therefore, we studied the post-functionalization of one product stemming from the dehydrogenative coupling and ethynylbenzene under micellar regime. Secondly, we successfully developed the Pd(II)-catalyzed redox neutral C(sp2)-H/C(sp2)-X coupling between (+)-limonene and bromoalkenes. This strategy, which is complementary with respect to the dehydrogenative coupling, needs a lower loading of the palladium catalyst and of the silver salt with respect to the previously studied coupling. Finally, we investigated the study of new approaches to cannabidiol (CBD). Of course, future work will be necessary to evaluate the strategies and reach the target
4
Vastine, Benjamin Alan. "Understanding mechanisms for C-H bond activation". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2679.
Texto completo
5
Khamker, Qudsia. "Ambiphilic C-H activation routes to heterocycles". Thesis, University of Leicester, 2014. http://hdl.handle.net/2381/28919.
Texto completoResumen
This thesis describes investigations of Cp*Rh- and (p-Cy)Ru-catalysed C-H functionalisation reactions of various substrates with alkynes and alkenes for the formation of several heterocycles and carbocycles. Mechanistic studies and DFT calculations are also presented. Chapter One includes a discussion of different mechanisms of C-H activation namely oxidative addition, σ-bond metathesis, 1,2-addition, electrophilic activation and AMLA/CMD. The applications of these different mechanisms of C-H activation in catalysis are also discussed with a particular emphasis on the use of AMLA/CMD in direct arylation reactions. Chapter Two gives an overview of stoichiometric and catalytic studies of AMLA C-H activation and subsequent reactivity with alkynes at Ir, Rh, and Ru. The results of Cp*Rh- and some (p-Cy)Ru-catalysed reactions of C-phenylpyrazoles with alkynes are presented. N-H and C-H activation occurs, leading to heterocycles. Mechanistic studies and DFT calculations show that C-H activation is reversible and rate limiting in the cases examined. Chapter Three is similar to Chapter Two but focusses on reactions with alkenes. The Cp*Rh-catalysed reactions of C-phenylpyrazoles with alkenes lead to mono or divinyl products which may undergo further aza-Michael cyclisations if the alkene is a good Michael acceptor. Mechanistic studies and DFT calculations are also discussed. Chapter Four deals with Cp*Rh-catalysed coupling reactions of other directing groups, including imidazole, imidazoline, pyrazolidinone, hydrazine, carboxylic acid and oxime with alkynes. Again, there is discussion on the different factors affecting product selectivity. Chapter Five gives a summary of all the conclusions on the work presented in this thesis. Throughout the thesis, all new compounds are characterised spectroscopically and several compounds have been characterised by X-ray crystallography.
6
Rossignol, Anne-Claude. "Activation métabolique par la prostaglandine H synthétase". Paris 5, 1993. http://www.theses.fr/1993PA05P111.
Texto completo
7
Wiley, Jack Scott. "C-H bond activation in iridium complexes /". Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8510.
Texto completo
8
Bu, Qingqing. "Ruthenium- and Cobalt-Catalyzed C-H Activation". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E4FC-F.
Texto completo
9
Hebert, Alexandra. "Mise au point de nouvelles techniques de radio-iodation et application au radiomarquage de molécules d'intérêt". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC413/document.
Texto completoResumen
Le radiomarquage de molécules d’intérêt avec des isotopes radioactifs est d'un grand intérêt pour la communauté scientifique, car il influe fortement sur le processus de découverte dans les sciences de la vie et en médecine nucléaire. Les molécules radiomarquées ont été largement utilisées pour évaluer les réactions biochimiques, pour mesurer la distribution in vivo d'une substance ou pour réaliser des tests RIA (RadioImmunoAssay). En médecine nucléaire, des radiopharmaceutiques pour la thérapie par ra-dio-isotopes (RIT) et des radiotraceurs pour des expériences d'imagerie telles que la TEP (tomographie par émission de positons), la tomographie par émission monophotonique (TEMP) ou la scintigraphie ont été décrites. Plusieurs isotopes de l'iode peuvent être utilisés à la fois pour le diagnostic et le traite-ment : 123I pour l'imagerie TEMP, 124I pour la TEP, 125I pour l'analyse biologique et 131I pour la radio-thérapie et la scintigraphie.Les méthodes classiques de radio-iodation reposent sur l'utilisation d'un précurseur pré-fonctionna-lisé, qui doit être synthétisé, isolé et purifié avant d'être introduit à l'étape de radio-iodation. La méthode par radioiododéstannylation est la méthode la plus populaire, bien que les précurseurs stannylés soient connus pour leur synthèse difficile et leur toxicité. Le développement de nouvelles méthodes de radio-iodation représente donc un grand intérêt dans le domaine de la radiochimie.Sur la base de travaux antérieurs, notre groupe a mis au point une méthode de radio-iodation de N-acylsulfonamides au moyen d’une radio-iodation C-H médiée par le palladium à température ambiante. Cette stratégie originale permet le radiomarquage de molécules d’intérêt dans des conditions très douces sans utiliser de précurseurs chimiques.Sur la base de la littérature, notre groupe développe actuellement une nouvelle méthode de radio-iodation de dérivés d’arylsilanes par radioiododésilylation dans des conditions douces. Cette méthodo-logie générale permet pour le moment le radiomarquage de dérivés d'arylsilanes activés en conditions doucesLabeling of (bio)molecules with radioactive isotopes is of high interest to for the scientific commu-nity, as it strongly impacts the discovery process in life science and nuclear medicine. Radiolabeled molecules have been extensively used to assess biochemical reactions, to measure in vivo distribution of a substance or to preform RIA (RadioImmunoAssay). In nuclear medicine, radio-therapeutics for RIT (RadioIsotope Therapy) and radio-tracers for molecular imaging experiments such as PET (Positron Emission Tomography), SPECT (Single Photon Emission Computed Tomography) or scintigraphy have been described. Several useful isotopes of iodine can be used for both diagnosis and therapy: 123I for SPECT imaging, 124I for PET imaging, 125I for biological assays and 131I for radio-therapy and scintig-raphy.Classical methods of radioiodination methods use a prefunctionalized precursor, which must be syn-thesized, isolated and purified before being introduced to the radio-iodination step. The radioiodode-stannylation method is the most popular method, although stannylated precursors are known for their difficult synthesis and their toxicity. The development of new methods of radioiodination is therefore of great interest in the field of radiochemistry.Based on a previous work, our group has developed a method to radio-iodinate N-acylsulfonamides through a room temperature palladium mediated C-H radio-iodination. This original strategy allows radiolabeling of biomolecules in very mild conditions without the use of chemical precursors.Based on literature, our group is now developping a new method to radio-iodinate arylsilyl derivates through radioiododesilylation in mild conditions. This general methodology allows for the moment the radiolabeling of activated arylsilyl derivates in mild conditions
10
Chow, Catherine. "C-H activation by a tungsten trimethylsilylallyl complex". Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42646.
Texto completoResumen
Thermolysis of Cp*W(NO)(Np)(η³-CH₂CHCHSiMe₃) generates a 16-electron allene
intermediate complex that selectively activates hydrocarbons at their methyl groups. In the
case of linear alkanes, only terminal activation is observed. This selectivity persists in the
presence of an ether functionality, but not of other oxygen-containing substrates such as
aldehydes and alcohols. With these latter substrates, oxidation of the complex to
Cp*W(O)₂Np has been noted. The existence of the allene intermediate has been verified by
two thermolytic experiments, and kinetic studies show that Cp*W(NO)(Np)(η³-
CH₂CHCHSiMe₃) is consumed according to pseudo-first-order kinetics during C–H bond
activation. The neopentyl ligand can be functionalized by reaction with CO, and the resulting
acyl complexes undergo chemical exchange on a slow timescale. The congeneric Mo
complex has also been synthesized, and although this complex is equally capable of
generating the η²-allene intermediate, its preferred mode of reactivity is coupling of the allyl
and alkyl ligands. As a result, the Mo complex is inferior to the W system for C–H
activation.
The thermolysis of Cp*W(NO)(Np)(η³-CH₂CHCHSiMe₃) in benzene has been
studied since the major products of this reaction each contain a 1,3-disubstituted allyl ligand
which might reduce reactivity at the allyl ligand in subsequent chemistry. In thermolytic
conditions, the resulting disubstituted allyl hydride complex undergoes no apparent reaction
with alkanes, but with deuterobenzene, deuterium incorporation into the allyl ligand is
observed. In addition to H/D exchange, the hydride ligands in these complexes can also migrate onto the allyl ligand, forming an η²-olefin complex that can be trapped as the
pyridine adduct.
The activation of fluorobenzenes by Cp*W(NO)(Np)(η³-CH₂CHCHSiMe₃) was also
studied, and in these substrates, exclusive activation of the C–H bond is observed. Migration
of the newly formed aryl ligands onto the allyl ligand does not occur when there is a fluorine
atom in the ortho position, which is probably due to the reduced nucleophilicity of the ligand
relative to the unfluorinated phenyl ligand. Selectivity in the activation of C–H bonds in
fluorobenzenes appears to be determined by sterics.
11
Luo, Junfei. "Controlling regioselectivity and enantioselectivity in C-H activation". Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9550.
Texto completoResumen
The direct functionalisation of C-H bonds has emerged in recent years as an efficient and atom-economic alternative to the traditional cross coupling reaction. One of the challenges towards this goal is the selective transformation of a particular C-H bond amongst many other C-H bonds. This thesis describes studies on the use of CO2 as a traceless promoter for controlling meta-regioselective arylation of phenols and a separate investigation into an enantioselective arylation of pre-chiral η6-arene tricarbonyl chromium complexes. The introduction provides a general review of recent advances in the use of coordinating moieties as directing groups for selective activation of aromatic C-H bonds. The challenge of meta-selective C-H activation and the direct functionalisation of phenols is assessed and discussed. To overcome the scarce methods for accessing meta-arylated phenols, our objective was to develop an efficient methodology for the meta-arylation of phenols. Our strategy includes an ortho-carboxylation of the phenol followed by ortho-arylation of the salicylic acids and the subsequent protodecarboxylation to afford meta-arylphenols is proposed. A step-wise approach towards our aim is applied. First, a convenient and efficient method for the carboxylation of phenols is presented in Chapter 2. Then, a tandem arylation/decarboxylation reaction of salicylic acids is described in Chapter 3. Last, an efficient methodology for the meta-arylation of phenols via carboxylation/arylation/ decarboxylation processes in one-pot is presented in the following section in Chapter 3. To demonstrate the utility of this powerful methodology, an efficient synthesis of γ-secretase inhibitor and the further transformation of the meta-arylphenols are shown. Furthermore, an alternative method is described for the synthesis of meta-arylphenols via a tandem oxidation/arylation/decarboxylation reaction of salicylaldehydes. In Chapter 4, an approach towards the development of enantioselective C-H arylation leading to planar chirality is stated. Preliminary results are presented for this ongoing project.
12
Müller, Thomas. "C-H Activation by Nickel and Iron Catalysis". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0003-C189-8.
Texto completo
13
Gao, Longhui. "C-H bond activation catalyzed by Ruthenium nanoparticles". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS348/document.
Texto completoResumen
Les molécules marquées par des isotopes de l’hydrogène possèdent de nombreuses applications dans divers domaines tels que la chimie, la biologie ou en science des matériaux. Dans le domaine de la recherche de nouveaux médicaments, les études liées à la pharmacocinétique nécessitent un accès rapide à des molécules marquées afin de ne pas impacter les coûts et les délais de développement. Le développement de la métabolomique a aussi entrainé une augmentation du besoin en molécules marquées isotopiquement. En effet, les molécules deuterées peuvent être utilisées en tant qu’étalons internes pour la quantification rapide des métabolites présents dans des tissus ou des fluides biologiques. La première partie de cette thèse concerne le développement d’une méthode générale de marquage de motifs de type thioéther dans des molécules complexes à l’aide d’une nouvelle réaction d’échange isotopique (catalysée par des nanoparticules de Ruthénium). D’un point de vue fondamental cette transformation représente le premier exemple de (Csp³)-H activation dirigée par un atome de soufre. En termes d’application, cette nouvelle réaction permet la synthèse rapide d’étalons internes pour la quantification LC-MS/MS et le marquage tritium de molécules complexes. La seconde partie de cette thèse relate le développement d’une nouvelle méthode d’homocouplage de phénylpyridines catalysée par Ru/C. Différents substrats comportant des substituants riches et pauvres en électron ont été couplés avec de bons rendements. Ces dimères ont ensuite été utilisés pour synthétiser de nouveaux complexes de bore dont les propriétés photophysiques ont été étudiées. Dans une troisième partie, la mise au point d’une réaction palladocatalysée permettant d’obtenir des molécules polycycliques contenant un motif de type pyridine est développéeDeuterated and tritiated compounds are widely used in numerous applications in chemistry, biology and material science. In the drug discovery and development process, ADME studies require quick access to labelled molecules, otherwise the drug development costs and timeline are significantly impacted. The rapid development of metabolomics has also increased the need for isotopically labelled compounds. In particular, deuterated molecules are used as internal standards for quantitative LC-MS/MS analysis of metabolites in biological fluids and tissues. In this context, a general method allowing the deuterium and tritium labelling of bioactive thioethers using a HIE reaction is described in the first chapter. From a fundamental point of view, this transformation is the first example of (Csp³)-H activation directed by a sulfur atom. In terms of application, this new reaction has been proved to be useful for the preparation of deuterated LC-MS/MS reference materials and tritiated pharmaceuticals owning high specific activity.In the second chapter of this manuscript, the development of a method allowing the cross-dehydrogenative homocoupling of 2-arylpyridines catalyzed by Ru/C is developed. Various substrates with different substituents were efficiently coupled to give the desired dimers in good yield. In terms of application, a series of pyridine-boron complexes derived from the phenyl pyridine dimers were also synthesized and their photophysical properties were studied.In the third chapter, a regioselective palladium catalyzed intramolecular arylation reaction allowing the synthesis of pyridine containing polycyclic compounds is described
14
Biswas, Achintesh Narayan. "C-H bond activation by transition metal complexes". Thesis, University of North Bengal, 2010. http://hdl.handle.net/123456789/1362.
Texto completo
15
Zhang, Shoukun. "Selective C–H Activation by Ruthenium(II) Carboxylate and Nickelaelectro-Catalysis". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://hdl.handle.net/21.11130/00-1735-0000-0005-155B-E.
Texto completo
16
Sykes, Alison Cartwright Brookhart Maurice S. "Investigations of C-H and N-H activation with electron deficient iridium pincer complexes". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,361.
Texto completoResumen
Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2006.Title from electronic title page (viewed Oct. 10, 2007). " ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry.
17
Macdonald, Margaret G. Templeton J. L. "Hydrocarbon C-H activation with Tp[prime]Pt complexes". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,788.
Texto completoResumen
Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Dec. 18, 2007). " ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry. On t.p., [prime] is the mathematical symbol.
18
Boutadla, Youcef. "Acetate-assisted C-H activation : mechanism, scope and applications". Thesis, University of Leicester, 2010. http://hdl.handle.net/2381/8592.
Texto completoResumen
This thesis describes mechanistic investigations of acetate assisted C-H activation, the synthesis of cyclometallated complexes containing nitrogen donor ligands via this method and the applications of cyclometallated complexes in terms of insertion reactions. Chapter one introduces the synthesis, by C-H activation, of cyclometallated complexes containing C,N bidentate ligands of palladium, ruthenium, rhodium and iridium. The introduction also gives an overview on the mechanisms of C-H activation and the applications of C-H activation in catalysis, particularly in direct arylation. Chapter two provides an introduction to the synthesis of arene ruthenium and Cp*M (M = Ir, Rh) half sandwich cyclometallated complexes). The scope of cyclometallation via acetate- assisted C-H activation with different directing groups (pyrazole, pyridine, imines, imidazole, oxazoline and triazole) is discussed. The methodology is extended to six membered rings, non aromatic sp2 and sp3 C-H bonds. Mechanistic investigations using bidentate ligands showed that chelating ligands can prevent the C-H activation process. Chapter three describes a joint computational and experimental study of the cyclometallation reactions of dimethylbenzylamine (DMBA) with [IrC12Cp*]2 using a range of chelating bases. DFT calculations show that facile C-H bond cleavage occurs via 'ambiphilic metal ligand activation' (AMLA) and the ease of C-H activation is governed by the accessibility of the K2-xl base displacement step; thus, more weakly coordinating bases promote C-H activation. Chapter four reports the reactivity of cyclometallated half-sandwich complexes (synthesised in chapter two). Alkynes are shown to insert into the M-C bond. In some cases C-N bond formation occurs to form a heterocycle. The product formed depends on the ease of the reductive elimination step. The relevance of these results to the catalytic synthesis of hetero-and carbocycles is discussed. Throughout the thesis all new compounds are fully characterised spectroscopically and by elemental analysis and several compounds have been structurally characterised by X-ray crystallography.
19
Ravetz, Megan Sarah. "Effect metal electron density on C-H activation reactions". Thesis, University of Salford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360458.
Texto completo
20
Fowles, E. H. "Transition metal multihydrides and aspects of C-H activation". Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233726.
Texto completo
21
Fan, Cheng. "Dichloroboryls, diboration and C-H activation with platinum complexes". Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443267.
Texto completo
22
Ren, Xinkun. "A P450 BM3 toolkit for C-H activation synthesis". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:1a41b822-3ba6-4116-af79-ad268e382a95.
Texto completoResumen
Cytochrome P450s are a superfamily of haem-dependent enzymes that catalyse the oxidation of natural organic compounds, most commonly via insertion of an oxygen atom from atmospheric dioxygen into a carbon-hydrogen bond. Since there is widespread interest in the selective functionalisation of C-H bonds, P450s have been extensively studied and evolved, particularly P450BM3 from Bacillus megaterium, which is catalytically self-sufficient. In this thesis, a P450BM3 variant library has been developed based on four 'generic accelerators', which have showed enhanced activity towards a broad range of non-natural substrates such as polyaromatic hydrocarbons and terpenes. The library was refined to 48 variants based on the screening results in order to maintain diversity of substrate pocket topology for oxidising a broad coverage of organic molecules. Successful applications include drug metabolism, drug fragment diversification, synthesis of flavour and fragrance compounds, steroid oxidation, late-stage functionalisation in total synthesis, and C-H amination. Total conversion was observed in most cases with a sufficient turnover number that enabled all the products to be fully characterised by NMR and MS. Two novel P450 activities were discovered as oxidative decarboxylation of an a-hydroxy carboxylic acid and C-H amination. The substrate range and varied product profiles suggest that this enzyme library is a good basis for developing selective C-H activation catalysts while expanding the P450 catalytic repertoire to include reactions important in synthetic chemistry, potentially opening new opportunities for biocatalysis.
23
Palazzolo, Alberto. "Development of new methods for the hydrogen isotope exchange catalyzed by metallic nanoparticles". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS276.
Texto completoResumen
Les composés marqués aux isotopes de l’hydrogène possèdent des nombreuses applications lors des phases précliniques de développement des médicaments. Par exemple, les composés deutérés sont utilisés comme étalons internes dans la quantification par LC-MS de métabolites alors que les molécules tritiées sont souvent des radiotraceurs de choix dans les études d’absorption, distribution, métabolisme et excrétion (ADME) moléculaire des candidats médicaments. Après une brève introduction, un premier chapitre discutera du développement d’une méthode douce et sélective, catalysée par des nanoparticules de ruthénium, qui permet d’effectuer le marquage en une étape de bases azotées et de médicaments dérivés. En changeant le ligand qui stabilise le nanocatalyseur, on a réalisé des échanges isotopiques compliqués tels que des tritiations en utilisant une pression sous-atmosphérique de tritium gaz et des deutérations d’oligonucleotides sensibles. Le chapitre suivant décrira la modification des catalyseurs commerciaux à base de ruthénium grâce à la coordination de carbènes N-hétérocycliques (NHCs). La modification assure une régio- et une chimiosélectivité améliorées lors de la deutération d’alcools aliphatiques. Certains des catalyseurs modifiés ont permis l’échange hydrogène/deutérium sur des molécules, particulièrement sensibles à la réduction, qui n’ont pas pu être isolées en utilisant le catalyseur commercial. Dans le dernier chapitre, la synthèse et l’évaluation de l’activité catalytique des nanoparticules à base d’iridium seront discutées. Ces nanocatalyseurs ont démontré une réactivité intéressante dans le marquage des composés complexes. Dans certains cas, les nanoparticules d’iridium ont permis l’incorporation de deutérium sur des positions inhabituelles en comparaison avec d’autres réactions d’échange isotopique déjà décritesHydrogen isotopes labelled compounds possess a broad range of application in the early pre-clinical phases of drug development process. For instance, deuterated compounds are applied as internal standard in quantitative LC-MS techniques while tritiated molecules are often the preferred radioactive tracers for the study of molecular absorption, distribution, metabolism and excretion (ADME). After a brief introduction, a first chapter will discuss the development of a mild and selective method to perform late stage labelling of variously functionalized nucleobases and drug analogues catalyzed by ruthenium nanoparticles. By changing the ligand which stabilizes the nanocatalyst, we achieved challenging isotopic exchanges such as tritiations of pharmaceuticals using subatmospheric pressure of tritium gas and deuteration of sensible oligonucleotides. The next chapter will describe the modification of commercially available ruthenium nanocatalysts via the coordination of N-Heterocyclic carbenes (NHCs). The modification granted enhanced regio and chemoselectivity for the deuteration of aliphatic alcohols. Some of the modified ruthenium catalysts allowed the hydrogen/deuterium exchange on easily reducible compounds which were not obtainable using the unmodified commercial catalyst. The final chapter will discuss the synthesis and the evaluation of the catalytic activity of iridium nanoparticles. The latter, showed an interesting reactivity for the labelling of challenging substrates. In some of the investigated compounds, IrNps were able to introduce deuterium with unusual regioselectivities compared to already described hydrogen isotope exchange reactions
24
Pierre, Cathleen. "Synthèses de molécules polycycliques par arylation C(sp³)-H intramoléculaire catalysée par le palladium". Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00975446.
Texto completoResumen
La synthèse de produits complexes se doit de prendre en compte de nouvelles méthodes desynthèse plus efficaces, dont la fonctionnalisation de liaisons carbone-hydrogène. Dans cecontexte, la catalyse homogène par les métaux de transition s'est avérée performante, tout encontrôlant la régio- et la chimiosélectivité de la réaction. Les travaux de thèse présentés dansce manuscrit témoignent de l'efficacité de cette stratégie pour la construction rapide decomplexité moléculaire.Dans un premier temps, nous nous sommes intéressés à l'utilisation de précurseurs chlorés, cequi a permis d'étendre significativement le champ d'application de l'arylation C(sp3)-Hintramoléculaire pallado-catalysée. Ces travaux ont conduit à la synthèse de nombreuxhétérocycles, difficilement accessibles par d'autres voies de synthèse plus traditionnelles.Dans un deuxième temps, le développement d'une méthodologie de double arylation C-Hnous a permis de synthétiser des molécules polycycliques aux squelettes originaux. Une seuleet même espèce catalytique permet dans ce cas de réaliser les deux opérations d'activation CHavec succès.Par la suite, nous avons montré qu'il était possible de synthétiser des composés énantioenrichispar arylation C(sp3)-H intramoléculaire asymétrique. Pour cela, les ligands chiraux detype phosphépine se sont avérés particulièrement performants, et induisent desénantiosélectivités prometteuses.Enfin, notre attention s'est portée vers la synthèse de polycycles par arylation C(sp3)-Hintramoléculaire deshydrogénante. Les résultats encourageants obtenus apparaissent commeune preuve de concept dans ce domaine, où très peu de travaux de recherche ont été rapportés.
25
Pahls, Dale R. "Pathways for C—H Activation and Functionalization by Group 9 Metals". Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801909/.
Texto completoResumen
As fossil fuel resources become more and more scarce, attention has been turned to alternative sources of fuels and energy. One promising prospect is the conversion of methane (natural gas) to methanol, which requires an initial activation of a C-H bond and subsequent formation of a C-O bond. The most well studied methodologies for both C-H activation and C-O bond formation involve oxidation of the metal center. Metal complexes with facile access to oxidation states separated by four charge units, required for two subsequent oxidations, are rare. Non-oxidative methods to perform C-H bond activation or C-O bond formation must be pursued in order for methane to methanol to become a viable strategy. In this dissertation studies on redox and non-redox methods for both C-H activation and C-O bond formation are discussed. In the early chapters C-O bond formation in the form of reductive functionalization is modeled. Polypyridine ligated rhodium complexes were studied computationally to determine the properties that would promote reductive functionalization. These principles were then tested by designing an experimental complex that could form C-O bonds. This complex was then shown to also work in acidic media, a critical aspect for product stabilization. In the later chapters, non-oxidative C-H activation is discussed with Ir complexes. Both sigma bond metathesis and concerted metalation deprotonation were investigated. For the former, the mechanism for an experimentally known complex was elucidated and for the latter the controlling factors for a proposed catalyst were explored.
26
Thongpaen, Jompol. "Ligands NHCs bifonctionnels en fonctionnalisation C-H métallo-catalysée". Thesis, Rennes, Ecole nationale supérieure de chimie, 2019. https://www.ensc-rennes.fr/formations/doctorats.
Texto completoResumen
La fonctionnalisation directe des liaisons Carbone-hydrogène (C-H) a pris, au cours des deux dernières décennies, une place de plus en plus importante en synthèse organique. En particulier, la fonctionnalisation CH catalysée par un métal de transition (TM) a connu une amélioration croissante de ses performances, permettant ainsi d'élargir la palette d'outils disponibles pour la synthèse de matériaux organiques, de produits naturels et de principes actifs. Néanmoins, le développement de nouvelles transformations de liaisons C-H fonctionnant efficacement en conditions douces avec une large tolérance aux groupements fonctionnels et une sélectivité élevée reste un enjeu majeur. Parallèlement, les carbènes N-hétérocycliques (NHCs) sont devenus des ligands de choix en chimie de coordination et en catalyse. Leurs propriétés uniques sont a l’origine de catalyseurs robustes de métaux de transition permettant des stratégies de synthèse plus efficaces. Cependant, l'utilisation des ligands NHCs dans des procédés métallo-catalysés de fonctionnalisation C-H reste a ce jour limitée. Par ailleurs, les composes organoborés sont des intermédiaires polyvalents en chimie de synthèse. Les stratégies mettant en jeu la fonctionnalisation C-H représentent sans nul doute l’approche la plus simple pour accéder a ces blocs de synthèse. Cette Thèse décrit une stratégie efficace et simple pour la préparation de complexes de métaux de transition portant des ligands chélates de type NHC-carboxylate sans précédent dans la littérature. Ces complexes, présentent une efficacité et une sélectivité élevée en tant que catalyseurs dans des réactions de borylation regiosélective de liaisons C-H dites ≪ inertes ≫ en conditions douces, et notamment photochimiquesThe direct functionalization of inert CH bonds has emerged over the past two decades as an increasingly important synthetic tool. In particular, transition metal (TM)-catalyzed C-H functionalization has witnessed continuing improvements in performance, allowing expansion of the toolbox available for organic material synthesis, natural products synthesis, and drug-discovery programs. In spite of this success, there is still a need for the development of methodologies to efficiently enable C-H bond transformation under mild conditions. During the past two decades, N-heterocyclic carbenes (NHCs) have become ubiquitous ligands in coordination chemistry and catalysis. Their unique properties, including strong σ- donation, are responsible for forming robust TM catalysts that allow for the development of more efficient synthetic procedures. Nevertheless, the use of NHC ligands in transition metal-catalyzed C-H functionalization has remained limited. Because organoboron compounds are versatile intermediates in synthetic chemistry, the development of new catalytic systems for selective borylation of unactivated C-H bonds would afford new perspectives in organometallic and catalysis. Herein, this Thesis discloses an efficient and straightforward strategy to access various types of transition metal complexes bearing bidentate NHC-carboxylate ligands which were fully characterized including solid-state structures. These unprecedented complexes possessing chelating-NHC ligands exhibited high efficiency and selectivity in site selective borylation of inert C-H bonds under mild conditions including a photosensitizer-free photocatalytic conditions
27
Li, Xing. "Histamine H¦3 activation depresses cardiac function in experimental sepsis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ41733.pdf.
Texto completo
28
Duin, Marcel Adrianus. "Nucleophilic and electrophilic platinum compounds for C-H bond activation". [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/75218.
Texto completo
29
Lopez, Suarez Laura. "Tetra-substituted olefin synthesis using palladium-catalysed C-H activation". Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/5869.
Texto completoResumen
In an effort to obtain more efficient and greener chemical transformations, a substantial amount of research interest has been directed towards the use of arene C-H bonds as functional groups. Hydroarylation of alkynes through direct functionalisation of C-H bonds has been studied in recent years leading to the development of high-yielding metal-mediated processes. The main aim of the current work is the addition of a third component in the hydroarylation of alkynes trough C-H activation, in order to achieve a second C-C bond formation. Attempts at palladium-catalysed three-component reaction of unactivated indoles with alkynes and aryliodides are described. The three-component reaction was studied in the intermolecular mode with both aryliodides and the more reactive diaryliodonium salts. These latter regents are reactive arylating and oxidising agents and have been used in the direct arylation of indoles under mild conditions through a PdII-PdIV catalytic cycle. In both cases the three-component product was not obtained. The intramolecular version of the reaction using alkyne-tethered indoles and diaryliodonium salts is also described. In this case the tandem process was successful, especially when using ethynylbenzyl indole derivatives, the Z-tetrasubstituted olefins could be selectively obtained under mild conditions. Finally, a low-yielding synthesis of chromenes from propargylaryl ethers and diaryliodonium salts is also discussed.
30
Liu, Xin-Zhu. "Development of late transition metal catalysed direct C-H activation". Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530451.
Texto completo
31
Black, Stephen Ian. "Synthetic and mechanistic studies related to C-H bond activation". Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/46966.
Texto completo
32
Crosby, Sarah H. "Cyclometallated complexes of platinum : C-H activation, oxidation and reduction". Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/55449/.
Texto completoResumen
Within this thesis, research related to the synthesis of Pt(II) and Pt(IV) cyclometallated complexes involving both aryl and alkyl C-H activation is discussed. The introduction reviews literature relevant to C-H activation, cyclometallation and reductive elimination, both historic and current. Four pyridine based pro-ligands, all with a 4-fluorophenyl substituent and a varying alkyl substituent, were synthesised in order to study both aryl and alkyl C-H activation. Initial reactions with K2PtCl4 led to the cyclometallation of the phenyl ring via a reversible aryl C-H activation, which then resulted in a variety of Pt(II) complexes by the addition of different co-ligands. Oxidation of these Pt(II) species gave Pt(IV) complexes, which subsequently underwent isomerisation to give the thermodynamic product. For the DMSO derivatives this was shown to occur via five coordinate complexes stabilised by agostic interactions with the alkyl chain and resulted in the first crystallographically characterised oxygen bound DMSO Pt(IV) complexes. Pt(II) and Pt(IV) sp2 cyclometallated complexes, each with an sp3 agostic interaction, were isolated and characterised when using the more sterically demanding tbutyl derivative of the pro-ligand. Subsequent alkyl C-H activation of the tbutyl group was observed via an intra-molecular transcyclometallation reaction to give complexes with an sp3 cyclometallation. From these species a series of complexes with a C(sp2)^N^C(sp3) tridentate ligand were also synthesised. It was also noted that a reversible rollover reaction of the Pt(II) agostic complex occurred in DMSO solvent by exchanging the C(sp2)^N cyclometallation for a C(sp2)^C(sp2) cyclometallation via decyclometallation, rotation about the central C-C bond and subsequent C-H activation. Reductive elimination of a chloride ligand with both sp2 and sp3 cyclometallated carbons occurred to give functionalised phenyl rings and tbutyl groups, respectively. Steric interactions were shown to play a major role in these reactions.
33
Lackner, Sebastian. "Nickel-Catalyzed Secondary Alkylations and Fluoroalkylations via C–H Activation". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-87C8-1.
Texto completo
34
Nako, Adi Edmund. "E-H bond activation by d⁰ and d¹⁰ metal centres". Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/44041.
Texto completoResumen
In recent years there has been a drive to study the catalytic dehydrocoupling of various protic and hydridic partners that contain E-H bonds (E = C, N, P, B, Si, Sn). This is in part due to the high atom-efficiency of these reactions as well as their ability to release dihydrogen in a controlled and potentially reversible manner. Transition metal complexes have historically been employed as catalysts for these reactions. Nevertheless, in recent years there has been growing interest in using complexes of the rare earth and main group metals to the same end. For these redox reluctant metals, the lack of multiple stable oxidation states makes σ-bond metathesis the predominant mechanistic step. This contrasts with the common two-electron and one-electron pathways often observed for transition metals. A diverse selection of mechanistic pathways have emerged with complementary activities and selectivities often reported for transition metal and non-transition metal systems. This thesis describes the activation of various E-H (E = C, Si, N, Al, Zn) bonds by do and d10 metal centres in both catalytic and stoichiometric regimes. The [Y{N(SiMe3)2}3] catalysed C-H silylation of triphenylphosphonium methylide with phenylsilane to give Ph3PCHSiH2Ph is reported. This is the first known example of C-H silylation of an ylide, and was found to be highly dependent on the nature of the pre-catalyst. Whilst exploring the reaction chemistry of the same yttrium complex, the first known example of the catalytic dehydrocoupling of Al-H/N-H bonds was discovered. This latter reaction offers a new synthetic route to form Al-N σ-bonds from sterically hindered alane and amine partners. The yttrium mediated dehydrocoupling of Si-H/N-H bonds is also documented with an emphasis on the potential for ligand acceleration of catalysis by a cyclometalated phosphonium ylide complex. As part of these studies, the synthesis of a series of structurally diverse aluminium hydride complexes is discussed. These complexes were not only investigated in the aforementioned dehydrocoupling reaction, but also as ligands for transition metals in their own right. The coordination of both Al-H and related Zn-H σ-bonds to copper(I) was observed in both solution and the solid state and this interaction was characterised by a number of spectroscopic techniques.
35
Dupont, Jairton. "Activation-fonctionnalisation intramoleculaire de liaisons c-h par le palladium". Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13197.
Texto completo
36
Cooper, Stephen P. "The formation of polyheterocycles via palladium-catalysed C-H activation". Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682181.
Texto completoResumen
A new PdII-catalysed interrupted oxidative-Mizoroki-Heck reaction has been developed. This reaction enables the synthesis of a wide range of polyheterocycles in a single step starting with simple substrates and involves the addition of a tethered diene unit across two joined heterocycles. The reaction has proven to be general for dienes tethered to indoles and pyrroles (in blue) and for 1t-allylcapturing heterocycles such as furan, thiophene and pyrrole (in red). In some cases the non-oxidized variant can be obtained through careful choice of oxidant and reaction conditions The scope and mechanism of this reaction have been explored leading to the proposed mechanism shown below. C-H activation of the first, tethered, heterocycle (in this case pyrrole), leads to migratory insertion of the pendant alkene and rapid capture of the π-allyl system by the second heterocycle (in this case furan). Initial products show complete diastereoselectivity and in some cases can be isolated, or oxidized in situ to fully aromatic systems
37
Dupont, Jairton. "Activation-fonctionnalisation intramoléculaire de liaisons C-H par le palladium". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376133600.
Texto completo
38
Paine, Belinda Marie. "Ruthenium N-heterocyclic carbene complexes : C-H activation and catalysis". Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425799.
Texto completo
39
Zakrzewski, Jacek. "Design of flow processes for C-H activation-type reactions". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/277176.
Texto completoResumen
The last 15 years have seen tremendous advances in using different metal catalysts to functionalize traditionally unreactive C–H bonds. Given the high potential of these seemingly ideal strategic bond forming reactions, the uptake of C–H activation in fine chemical manufacture is slow. Part of the reason for this deficiency is limited mechanistic understanding of these complex reactions. This can preclude industrial applications of either batch or continuous C–H activation processes. Owing to the synthetic utility of C–H activation reactions, it is highly desirable to design intensified processes for this family of transformations, what can possibly facilitate industrialisation of C–H activation reactions. Firstly, an ab initio process design of a novel C(sp3)–H activation reaction giving access to aziridines yielded a predictive mechanistic model that has been used in an in silico optimisation. The identified set of conditions was suitable for a scalable continuous process. A separation technique was developed, and the utility of the process was extended by a subsequent reaction, a nucleophilic ring opening. Secondly, a black-box optimisation of the investigated reaction was performed. The applied algorithm was able to identify a set of conditions fulfilling the set targets within few experimental trails. The second project has set out to design a process for a C–H oxidative carbonylation. A kinetic study has shown that the reaction is CO-starved even at elevated pressures and that there is an optimal CO concentration. The turn-over number was increased from 8 to nearly 500. Two scalable processes were then developed. The first was a batch process, characterised by a very low catalyst loading. The second was, to the best of author’s knowledge, the first continuous process for an oxidative carbonylation reaction. The continuous process was tested on several oxidative carbonylations yielding excellent results with virtually no optimisation performed. Finally, an environmental sustainability assessment was performed using both, simplified metrics and an LCI analysis. The developed mechanistic understanding allowed identification of sources of inherent inefficiencies of C–H activation reactions. Appropriate solutions to these obstacles were suggested. Thus, it is believed that a step towards generic principles of design of intensified, scalable processes for C–H activation-type reactions has been made.
40
Loup, Joachim. "Selectivity Control in 3d Transition Metal-Catalyzed C–H Activation". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0003-C19E-1.
Texto completo
41
Jerhaoui, Soufyan. "Sulfoxydes : novel strategy for the asymmetric C(sp3)-H activation". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF025/document.
Texto completoResumen
Pendant de nombreuses années, les liaisons C-H aliphatiques ont été considérées comme dormantes, difficilement exploitables dans le contexte de la chimie organique. Le défi le plus important est de sélectionner une liaison C-H parmi toutes celles que contient une molécule. L’approche la plus utilisée à ce jour est l’utilisation d’un groupement directeur qui permet, en se liant à un métal, de diriger l’activation d’une liaison C-H en particulier. Suite au développement des groupements bicoordinants, nous avons développé notre propre groupement bicoordinant chiral. Cet auxiliaire nous a permis de réaliser de nombreuses transformations diastéréosélectives sur des carbones aliphatiques telles que l'arylation et l'oléfination. Nous l’avons également utilisé pour développer une méthodologie innovante pour la synthèse de produits naturels. Suite à ces travaux, nous avons développé un nouveau ligand chiral qui a été utilisé dans l’arylation et l’alkynylation énantiosélectives de cycloalcanesOver the decades, non-activated C-H bonds have been considered as dormant functionalities, hardly exploitable in the context of multistep synthesis of complex scaffolds. The main challenge is to select one C-H bond among all contained in one molecule. To answer to this problem bicoordinating directing groups allowing directed C(sp3)-H activation have been developed. Following the work of Daugulis and Babu, we developed our own chiral bicoordinating directing group, (S)-2-(p-tolylsulfinyl)aniline. This chiral auxiliary allowed us to realise various diastereoselective transformations on aliphatic chains such as arylation, olefination oracetoxylation. We also used it to develop a brand-new methodology for the total synthesis ofcyclopropane-bearing natural products. Moreover we developed a new chiral sulfinyl ligand, N-((S)-1-(4-(tert-butyl)phenyl)-2-((R)-p-tolylsulfinyl)ethyl)acetamide, that has been used for the enantioselective arylation and alkynylation of cycloalkanes
42
Roudesly, Fares. "Fonctionnalisation C-H dirigée d'hétérocycles azotés". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS354.
Texto completoResumen
Ce travail de thèse a apporté sa contribution et de nouvelles connaissances dans le domaine de l’activation / fonctionnalisation C-H de noyaux azotés de type pyridine et pyrrole. D’abord, nous avons développé une méthode permettant l’allylation et l’oléfination régiosélective d’azines N-oxyde en utilisant un complexe de Pd(0) formé in situ. Le champ d’application de cette réactivité a ensuite été étudié. Des études expérimentales et des calculs DFT nous ont permis de proposer un mécanisme pour les étapes d’allylation et d’isomérisation. Nous proposons que l’étape d’activation C-H est l’étape cinétiquement déterminante du cycle catalytique et se fait selon un mécanisme de déprotonation/palladation par sphère externe. Ensuite, nous nous sommes intéressés à l’application de la réaction de Murai aux dérivés du 2- pyrrole carboxaldéhyde en utilisant un complexe de Ru(0). L’utilisation du monoxyde de carbone sous pression atmosphérique nous a permis d’obtenir les produits d’acylation en présence de différents vinylsilanes et styrènes. L’application de cette réactivité à d’autres dérivés du 2-pyrrole carboxaldéhyde est en cours d’étude au laboratoireThis thesis work has brought its contribution the field of C-H activation / functionalization of nitrogenous containing rings as pyridine and pyrrole. First, we developed a strategy for a Pd- catalyzed regioselective allylation and alkenylation of azine N-oxides. The scope of this reactivity has been studied. Experimental studies and DFT calculations allowed us to propose a mechanism for the allylation and isomerization steps. We propose that the C-H activation step is the rate determining step of the catalytic cycle, and that it takes place through an outer sphere deprotonation / palladation mechanism. Next, we applied the Murai reaction to 2-pyrrole- carboxaldehyde derivatives using a Ru(0) complex. Under an atmospheric pressure of carbon monoxide, we could obtain the acylated products in the presence of various vinylsilanes and styrenes. The application of this reactivity to other 2-pyrrole carboxaldehyde derivatives is under study in the laboratory
43
Fallon, Brendan. "Cobalt-catalyzed bond activation : C-H functionalization, hydrosilylation and coupling reactions". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066411/document.
Texto completoResumen
Dans cette thèse, nous nous concentrerons principalement sur l’utilisation de complexes basse-valence de cobalt bien définis de la famille des RCo(PMe3)4 pour l’activation de divers types de liaisons (C–H, Si–H, C–X). Notre but était de développer un système compétitif par rapport au système bimétallique de Yoshikai, mais aussi par rapport aux systèmes onéreux à base de rhodium. Nous avons démontré avec succès que les complexes isolés Co(PMe3)4 et HCo(PMe3)4 étaient des catalyseurs efficaces pour l’hydroarylation de différents alcynes et alcènes via une activation de liaisons C–H. De plus, nous avons fait une étude mécanistique en couplant des marquages au deutérium et des études de chimie théorique. Nous avons déterminé que la fonctionnalisation de liaisons C–H se faisait selon un mécanisme concerté appelé ‘’Ligand-to-Ligand Hydrogen Transfer’’ (LLHT). A partir de ces études, nous avons pu aussi développer une hydrosilylation hautement régio- et stéréosélective d’alcynes permettant d’utiliser un grand nombre de silanes différents. Nous avons pu au cours de cette étude isoler un nouveau complexe de cobalt(III) bis-hydrure jouant un rôle important dans le mécanisme. Enfin, nous décrivons aussi que ces mêmes complexes de cobalt RCo(PMe3)4 sont capables de catalyser l’homocouplage de bromure et chlorure de benzyle en présence de dimethylzinc. Une étude mécanistique préliminaire suggère que la réaction procède par deux transferts mono-électroniques et que le diméthylzinc permet de régénérer le catalyseurThis thesis has focused on the use of well-defined low-valent cobalt complexes of the family RCo(PMe3)4 for a variety of bond activation (C–H, Si–H, C–X). We aimed to develop a catalytic system that could compete with the previously reported bimetallic systems of Yoshikai and expensive rhodium catalysis. To this end, we successful demonstrated that Co(PMe3)4 and HCo(PMe3)4 are efficient catalysts for the hydroarylation of a broad variety of alkynes and alkenes. In addition, we carried out extensive mechanistic investigations using deuterium labelling experiments and theoretical studies namely DFT. The main finding of these studies was that the C–H bond activation proceeded via a ligand-to-ligand hydrogen transfer mechanism. Following on from this study we then showed that it was possible to carry out the regio- and stereoselective hydrosilylation of internal alkynes with a broad variety of hydrosilanes. During this study we successfully isolated an interesting cobalt(III) intermediate which we believe plays a crucial role in the reaction mechanism. Finally, we report on the ability of these catalysts to efficiently catalyze the homocoupling of benzyl halides in the presence of dimethylzinc. Initial mechanistic investigations suggest that the reaction takes via two single electron transfers and that dimethylzinc act to regenerate the catalyst
44
Zhang, Zhuan. "Late Stage Modifications of Phosphines using Transition-Metal-Catalyzed C–H Bond Functionalization". Thesis, Rennes, Ecole nationale supérieure de chimie, 2020. http://www.theses.fr/2020ENCR0067.
Texto completoResumen
L'objectif principal de cette thèse de doctorat porte sur la préparation de phosphines polyfonctionnelles par diversification tardive de ligands commerciaux. Nous avons développé l'alkylation la liaison C–H en position ortho' des biarylphosphines catalysée par le rhodium(I). Cette nouvelle méthodologie permet d'accéder facilement à une vaste bibliothèque de phosphines multifonctionnelles. Certains de ces ligands modifiés ont surpassé les phosphines disponibles dans le commerce dans la carboxylation des bromures d'aryle catalysée par le palladium avec du dioxyde de carbone en présence d'un catalyseur photoredox. Pour améliorer la diversité des biarylphosphines, nous avons également perfectionné l'alcénylation des liaisons C–H dirigées par l’atome de posphore(III) des (dialkyl)- et (diaryl)biarylphosphines à partir d'alcynes internes. Le [Rh(OAc)(COD)]2 sans chlorure est un meilleur catalyseur que le [RhCl(COD)]2. Les conditions ont été développées pour contrôler la mono- et la difonctionnalisation. Une de ces nouvelles (dialkyl)biarylphosphines bisalcénylées a été utilisée pour la préparation d'un complexe de palladium(II), et certains de ces ligands fonctionnalisés ont surpassé leurs phosphines non fonctionnalisées correspondantes dans l'amidation palladocatalysée de chlorures d'aryle encombrés. Enfin, nous avons également exploré un nouveau protocole pour l'alkylation des liaison C-H de phsophines via la formation des intermédiaires phosphine-ruthénium cyclométallé à 5 ou à 7 chaînons. Ces phosphines fonctionnalisées ont le potentiel d'améliorer les réactions de couplage croisé des (pseudo)halogénures d'aryle encombrésThe main objective of this PhD thesis deals with the preparation of polyfunctional phosphines by late-stage diversification of commercially available ligands. We have developed rhodium(I)-catalyzed ortho’- C–H bond alkylation of biarylphosphines. This new methodology provides a straightforward access to a large library of multifunctionalized phosphines. Some of these modified ligands outperformed commercially available phosphines in the Pd-catalyzed carboxylation of aryl bromides with carbon dioxide in the presence of a photoredox catalyst. To improve the diversity of biarylphosphines, we have also perfected the P(III)-directed C−H bond alkenylation of (dialkyl)- and (diaryl)biarylphosphines using internal alkynes. Chloride-free [Rh(OAc)(COD)]2 acts as a better catalyst than [RhCl(COD)]2. Conditions were developed to control the mono- and difunctionalization. One of these novel bisalkenylated (dialkyl)biarylphosphines was employed for the preparation of a palladium(II) complex, and some of these functionalized ligands outperformed their corresponding unfunctionalized phosphines in Pd-catalyzed amidation of sterically hindered aryl chlorides. Finally, we have also explored a novel protocol C–H bond alkylation of phosphines via 5- or 7- membered ring cyclometallated phosphineruthenium intermediates. These functionalized phosphines have potential to improve crosscoupling reactions of sterically hindered aryl (pseudo)halides
45
Li, Bin. "Ruthenium(II) catalyzed C-H bond functionalization and hydrosilylation reactions". Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S114.
Texto completoResumen
Dans ce travail de recherche, la synthèse de complexes de ruthénium cyclometallés a été effectuée à partir d'imines, 2-phénylpyridine, 2-phényloxazoline, phénylpyrazole, et benzo[h]quinoline par réaction avec [RuCl2(p-cymène)]2 et KOAc via une activation de liaison sp2 C-H. Le système [RuCl2(p-cymène)]2/KOAc/PPh3 est un catalyseur efficace pour réaliser la diarylation d'imines et de 2-phénylpyridine dans l'eau, solvant qui donne de meilleures activités que les solvants organiques. Des amines encombrées ont été préparées par une séquence catalytique activation C-H/arylation/ hydrosilylation d'imines catalysée par [RuCl2(p-cymène)]2. La monoarylation sélective de 2-pyridyl arylcétones, via la formation d'un intermédiaire ruthénacycle à 6 chainons plus difficile à former, est catalysée par l'espèce Ru(O2CC6H4CF3)2(p-cymène) formée in situ. L'alcénylation déhydrogénative oxydante directe d'aryloxazoline par du styrène et des acrylates est catalysée par le système [RuCl2(p-cymène)]2/BNPAH (1,1′-binaphthyl-2,2′- diylhydrogénophosphate) en présence de Cu(OAc)2.H2O utilisé comme oxydant sous air. La réaction tandem oxydation des 2-pyridylméthanols / mono- ou di-α-alkylation sélective de liaisons sp3 C-H de 2-pyridylcétones avec des alcènes fonctionnalisés a été catalysée par le complexe de [RuCl2(p-cymène)]2 en présence de Cu(OAc)2.H2O dans le DCE ou le toluène. Dans la deuxième partie de ce travail, le complexe [RuCl2(p-cymène)]2 a été utilisé efficacement en hydrosilylation catalytique d'imines et d'amides primaires. Nombreuses aldimines et cétimines ont été réduites chémosélectivement en amines correspondantes en utilisant le PMHS comme silane « vert » dans l'éthanol à température ambiante. De plus les amides primaires ont été sélectivement transformés en amines secondaires dans une réaction sans solvantIn this research doctoral thesis, we have shown that imines, 2-phenylpyridine, 2-phenyloxazoline, phenylpyrazole, benzo[h]quinoline led to cyclometallated ruthenium(II) complexes from [RuCl2(p-cymene)]2 and KOAc via sp2 C-H bond activation. [RuCl2(p-cymene)]2 /KOAc/PPh3 is an efficient catalytic system for diarylation of imines and 2-phenyloxazolines in water, which gave higher activity than in organic solvents. Bulky amines were then synthesized through sequential catalytic C-H arylation and hydrosilylation of imines using [RuCl2(p-cymene)]2 catalyst. Challenging selective mono arylation of 2-pyridyl arylketones, leading to six-membered ruthenacycle intermediate, difficult to perform, was achieved with in situ generated Ru(O2CC6H4CF3)2(p-cymene) catalyst. The direct dehydrogenative oxidative alkenylation of aryloxazolines with styrenes and acrylates was catalyzed by [RuCl2(p-cymene)]2/BNPAH (1,1′-binaphthyl-2,2′- diylhydrogenophosphate) catalytic system in the presence of Cu(OAc)2.H2O as an oxidant in air. Tandem catalytic oxidation of 2-pyridylmethanols and selective sp3 C-H (mono or di) α-alkylation of 2-pyridyl ketones with functional alkenes was performed by using [RuCl2(p-cymene)]2 complex in the presence of Cu(OAc)2.H2O in DCE or toluene. In the second part, it is shown that, [RuCl2(p-cymene)]2 is a very efficient catalyst for the hydrosilylation of imines and primary amides. A wide range of aldimines and ketimines were successfully reduced to corresponding amines in high chemoselectivity by using PMHS as greener silane in ethanol at RT. Moreover, challengingly, primary amides could be selectively converted by hydrosilylation to the secondary amines under solvent free conditions
46
Schinkel, Marvin. "Rutheniumkatalysierte Addition von nicht aktivierten C(sp²)–H- und C(sp³)–H-Bindungen an Alkene". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://hdl.handle.net/11858/00-1735-0000-0015-A380-B.
Texto completo
47
Tsang, Jenkins Yin Ki. "Intermolecular C-H activation effected by CP*W(NO)-containing complexes". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/926.
Texto completoResumen
Thermolysis of Cp*W(NO)(CH₂CMe₃)₂ (2.1) in halo, methoxy, or phenylethynyl-substituted benzenes leads to the formation of the alkylidene intermediateCp*W(NO)(=CHCMe₃) which selectively activates ortho C-H bonds of the organicsubstrates. The ortho-regioselectivity diminishes as the size of the substituent increasesfrom F (97 %) to C-=CPh (51 %). In the solid-state structure of all complexes the ortho-substituent is not coordinated to the metal centre; rather, the metal centre is engaged inagostic interactions with a neopentyl methylene C-H bond. Mechanistic studies on the chlorobenzene reaction reveal that the ortho-C-H-activation product is preferentially formed via thermal isomerization from the meta / para-C-H-activation isomers.
Reactions between Cp*W(NO)(CH₂EMe₃)Cl (E = C or Si) and a variety of bis(allyl)magnesium reagents lead to the expected formation of Cp*W(NO)(alkyl)(allyl)complexes. Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCH₂) (3.5), Cp*W(N0)(CH₂CMe₃)(η³-CH₂CMeCH₂) (3.6), Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHMe) (3.7),Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHPh) (3.8) and Cp*W(N0)(CH₂SiMe₃)(η³-CH₂CHCHMe) (3.9) have thus been synthesized in moderate yields. The solid-state molecular structures of 3.5 and 3.7-3.9 feature a σ-π distorted ally! ligand in the endoconformation. Complex 3.5 reacts with pyrrolidine at RT to form Cp*W(NO)(NC₄H8)(CHMeCH₂NC₄H8) (3.10), a nucleophilic-attack product. Complexes 3.6-3.9 effect the concurrent N-H and α-C-H activation of pyrrolidine at RT and form
alkyl-amido complexes analogous to the previously known Cp*W(N0)(CH₂EMe)(NC₄H₇-2-CMe₂CH=CH₂) (3.12).
Thermolysis of Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHMe) (3.7) at RT leads to the loss of neopentane and the formation of the η²-diene intermediate Cp*W(N0)(η²-CH₂=CHCH=CH₂) (A) which has been isolated as a PMe₃ adduct. In the presence of saturated organic substrates, C-H activation occurs exclusively at the methyl positions of the molecule. Reactions between intermediate A and unsaturated substrates lead to coupling between the coordinated η²-diene and the unsaturation on the organic molecule.Treatment of Cp*W(N0)(n-C₅H₁₁)(η³-CH₂CHCHMe) (4.1) with I₂ at -60 °C produces n-C₅H₁₁ I in moderate yields.
Thermolysis of Cp*W(N0)(CH₂CMe₃)(η³-CH₂CHCHPh) (3.8) in benzene at 75 °C for one day leads to the exclusive formation of Cp*W(N0)(H)(η³-PhCHCHCHPh) (5.1).Trapping, labelling, and monitoring experiments suggest that 5.1 is formed via 1) the loss of neopentane and the generation of the allene intermediate Cp*W(N0)(η²-CH₂=C=CHPh), 2) the C-H activation of benzene resulting in a phenyl phenylallyl complex, and 3) the thermal isomerization of this latter species to 5.1.
48
Bechtoldt, Alexander. "Aerobic Ruthenium-Catalyzed C–H Activations". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E492-A.
Texto completo
49
Holstein, Philipp. "Enantioselective C(sp3)-H Arylation and Development of a Modular C(sp3)-H Alkenylation". Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10286.
Texto completoResumen
Récemment, l'activation C-H catalysée par des métaux de transition est devenue un outil performant pour construire des liaisons carbone-carbone et carbone hétéroatome à partir de liaisons C-H omniprésentes dans les molécules organiques. Bien que l'activation des liaisons C-H aromatiques ait été largement étudiée ces dernières années, celle des liaisons C-H aliphatiques représente encore un domaine faiblement exploré. Notre équipe s'est depuis plusieurs années intéressée au développement méthodologique de l'activation C(sp3)-H et à son application en synthèse de produits naturels et molécules bioactives. Dans la continuité des récents travaux sur la version asymétrique de cette réaction, cette thèse décrit le développement et la synthèse de nouveaux ligands du type Binepine. Ces ligands chiraux et monodentates nous ont permis de réaliser la synthèse d'indanes chiraux possédant un centre asymétrique quaternaire, de manière hautement énantio- et diastéréosélective. Cette réaction présente comme avantages l'utilisation d'une faible charge catalytique et d'une température de réaction inférieure à 100 °C, sans aucun additif. Le champ d'application de la réaction inclut notamment l'activation des liaisons C-H d'un groupement méthylène, donnant ainsi accès à des systèmes fusionnés, tricycliques. La construction de molécules non-aromatiques via une alcénylation C-H intramoléculaire a été récemment décrite et s'avère très prometteuse pour la synthèse de produits naturels saturés. Dans la continuité de ces travaux innovants, nous avons développé la synthèse de γ-lactames à partir de bromoalcènes acycliques. Cette nouvelle réaction permet de construire de manière simple et efficace des hétérocycles a cinq chainons de façon modulaire, donnant ainsi la possibilité d'envisager des nouvelles déconnections rétrosynthétiques, complémentaires des méthodes déjà établies. Cette nouvelle méthode a pu être appliquée à la synthèse totale de l'alcaloïde marin Plakoridine A, dont la structure centrale cyclique a été synthétisée en quatre étapes avec un rendement global de 37%Recently, transition-metal-catalyzed C-H activation has emerged as a powerful tool to transform stable C-H bonds into carbon-carbon or carbon-heteroatom bonds. While the activation of aromatic C-H bonds has seen a tremendous development, less effort has been devoted to the more challenging activation of aliphatic C-H bonds. Our group has a long-standing interest in the development of C(sp3)-H activation reactions and their application in the synthesis of natural products and bioactive compounds. In line with previous efforts to develop an asymmetric C(sp3)-H activation, the herein presented work details the synthesis of new Binepine ligands. These monodentate, chiral ligands enabled us to realize a highly dia- and enantioselective C(sp3)-H activation reaction allowing the construction of chiral quaternary carbon centers. Strong points of this robust method are the low catalyst loading, the low reaction temperature and the absence of additives. The substrate scope includes the rare activation of methylene C-H bonds leading to fused tricyclic carbocycles and heterocycles. The construction of non-aromatic molecules through intramolecular C-H alkenylation was recently disclosed and has great potential for the construction of saturated natural products. Based on seminal work, we have developed the synthesis of valuable γ- lactams from acyclic bromoalkenes. This new methodology offers a powerful way to build simple, five-membered N heterocycles in a modular fashion. Notably, it enables a new retrosynthetic disconnection which is complementary to conventional approaches. Finally, we set out to showcase its utility as key step in the total synthesis of the pyrrolidine alkaloid Plakoridine A. The cyclic core structure was accessed in four steps and 37% overall yield
50
Coxon, Thomas. "Investigating rhodium-catalysed hydroacylation and carbon-carbon bond activation". Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:26111304-1563-4c18-956e-67636b87983a.
Texto completoResumen
The work described in this thesis documents the development of new rhodium(I)-catalysed methodologies within two areas of research. The first examines the use of carbonyls as chelating groups in hydroacylation to produce synthetically valuable ketones and enones. The second area explores new carbon-carbon bond activation methodologies. Chapter 1 presents a literature review of the historical development of rhodium-catalysed hydroacylation, with a focus on chelating groups that can currently be used to suppress decarbonylation. A brief review of methodologies that avoid the requirement for a tether is also included. Chapter 2 describes the development of a novel hydroacylation methodology employing carbonyl-based functional groups as tethers on aldehyde substrates. The chapter begins with the optimisation studies for the hydroacylation of β-formyl amides with terminal and internal alkynes, allenes and terminal alkenes, and subsequently explores the substrate scope for each case. The chapter then outlines the investigations undertaken with 1,4-dicarbonyl and 1,5-dicarbonyl systems, N-formyl amides, β-formyl esters and finally β-formyl ketones. A detailed description of the routes undertaken to synthesise each starting material is also presented. Chapter 3 presents a short review surveying the key milestones in the development of carbon-carbon activation methodologies. The chapter begins with a theoretical comparison to carbon-hydrogen activation and a discussion of the unique challenges that are faced. An overview of the major strategies employed to enact these processes is subsequently presented for both strained and unstrained substrates. Chapter 4 outlines the attempts undertaken to develop a novel carbon-carbon bond activation methodology. The work evaluates sulfur-, nitrogen- and alkene-based chelating groups, known to be successful in hydroacylation, in analogous ketone substrates. Chapter 5 discusses the conclusions from this work and the potential for further work. Chapter 6 presents the experimental procedures and data.