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Cai, Yingxiao. "Cobalt-catalyzed carbon-carbon bond formation by activation of carbon-halogen or carbon-hydrogen bonds." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX039/document.
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Ce travail de thèse présente le développement de nouvelles réactions de formation de liaisons carbone-carbone. Le premier chapitre décrit la cyanation d’arylzinciques par catalyse au cobalt à partir d’une source non toxique et bénigne, le N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS), et conduit à de bons rendements en benzonitriles correspondants. Dans cette réaction, le cobalt sert de catalyseur non seulement pour la formation des arylzinciques mais aussi pour la formation de liaisons C-CN. Les groupements fonctionnels, cétone et nitrile, sont permis lorsque le complexe de cobalt associé au ligand bipyridine est utilisé. Le deuxième chapitre porte sur l’homocouplage Csp3-Csp3. Un simple halogénure de cobalt permet de catalyser la dimérisation des halogénures d’alkyles et des acétates d’allyles avec de bons à d’excellents rendements. L’ajout d’iodure de sodium permet d’étendre cette réaction aux chlorures et tosylates d’alkyles. Le couplage croisé entre 2 halogénures d’alkyle différents a également été testé mais les conditions doivent être optimisées. Dans le troisième chapitre, le couplage croisé catalysé au cobalt entre des bromures vinyliques et des chlorures benzyliques est présenté. Des halogénures de vinyles et de benzyles porteurs de groupements electrodonneurs ou electroattrateurs peuvent ainsi être couplés efficacement avec rétention de la configuration de la double liaison. Un mécanisme radicalaire semble être impliqué. Enfin, le dernier chapitre décrit l’arylation d’une 2-phenylpyridine avec un arylzincique par catalyse au cobalt par activation d’une liaison C-H et conduit à de premiers résultats encourageantsThis thesis presents the development of cobalt-catalyzed carbon-carbon bonds formation. The first chapter describes a novel cobalt-catalyzed electrophilic cyanation of arylzinc species, employing benign and non-toxic N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS) as the cyano source. In this reaction, cobalt catalyzes both the formation of arylzinc species and the cyanation reaction. Various benzonitriles are synthesized affording good to excellent yields. Using cobalt-bipyridine complexes instead of CoBr2, ketone and nitrile groups can be tolerated. The second chapter reports cobalt-catalyzed Csp3-Csp3 homocoupling reaction. A simple catalytic system could deliver dimers of a number of alkyl halides/pseudohalides and allylic acetates. Sodium iodide is crucial for the homocoupling of unactivated alkyl chlorides and tosylates. This method is extended to alkyl-alkyl cross-coupling; however, the conditions still need to be optimized. The third chapter describes a cobalt-catalyzed vinyl-benzyl cross-coupling. A variety of functionalized vinyl bromides and benzyl chlorides are efficiently coupled under mild conditions in good to excellent yields, with retention of Z/E configuration. A few mechanistic experiments indicate a single electron transfer involved. The last chapter discusses the progress on the cobalt-catalyzed arylation of 2-phenylpyridine with an arylzinc species by C-H activation and promising results are obtained
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Shirakura, Masamichi. "Nickel-Catalyzed Additions of Acetylenic Carbon-Element Bonds to Carbon-Carbon Multiple Bonds." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120895.
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Rene, Olivier. "Advances in Palladium-Catalyzed Carbon-Carbon Bond Formation Via Functionalization of Carbon-Hydrogen Bonds." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28864.
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In the past decade, significant advances have been made in the formation of Csp2-Csp 2 bonds by direct arylation. However, this process generally requires the use of forcing conditions at temperatures typically above 100 °C, which limits the substrate compatibility as well as large-scale applications. Inspired by the recent advances in the development of milder reaction conditions for the arylation of electon-rich arenes in an aqueous medium, we describe that such reactivity is also possible with electron-deficient polyfluorinated arenes at room temperature under biphasic conditions. Several examples are included, highlighting the application of this method to the preparation of a variety of biaryls using iodides bearing electron-poor, electron-rich and sterically encumbering substituents. Several polyfluoroarenes with different substitution patterns are also tolerated. In addition, the method can be extended to the arylation of halogenated thiophenes in a regioselective fashion.
However, direct arylation conditions that are general for a broad variety of heterocyclic coupling partners are only sparsely reported and the use of a different set of conditions for each type of substrate remains the norm. As part of a program dedicated to the study of the direct arylation mechanism and the development of broadly applicable reaction conditions, we became interested in investigating the effect of electron-deficient biaryl-type phosphine ligands on the C-H bond cleavage step of this process under Pd(0) catalysis. Inspired by previous reports validating the efficiency of these types of ligands in intramomecular direct arylation, we have developed a new electron-deficient fluoroarylphosphine ligand that promotes C-H bond functionalization of a broad variety of heterocycles. The demonstrated ability of these types of ligands to facilitate the C-H bond cleavage step of this process has been assessed and experimental evidence suggests a concerted metalation-deprotonation mechanism in the presence of an electrophilic metal center.
Only recently, nonetheless, has attention been paid to the formation of Csp3-Csp2 bonds by the direct arylation strategy. As an alternative to the use of aliphatic halides as an entry point to a1kylpalladium(II) intermediates, we describe the use of a Heck-like cyclization of an aryl halide as a means of intercepting the key palladium(II) species, along with the first examples of domino Heck-arylation involving intermolecular capture with heterocyclic arenes via C-H bond cleavage. Several examples are presented, demonstrating the application of this method to the preparation of diverse dihydrobenzofurans, indolines and oxindoles substituted with sulfur-containing heterocycles such as thiazoles, thiophenes and benzothiophene.
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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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Dong, Boliang. "Formation of Carbon-Carbon and Carbon-Hetero Bonds through Gold Catalysis." Scholar Commons, 2017. https://scholarcommons.usf.edu/etd/7396.
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This dissertation mainly contains two parts: one is C-X (C, O, S) bond formation through gold(I) catalysis, one is new applications via gold(I/III) redox catalysis.
In first part, gold(I) catalysts would be introduced and their general applications, then the TA-Au species will be emphasized including the design, synthesis, characters and their application in catalysis. The applications are well developed during the past decade in our group, but here only involves three examples regarding C-C, C-O and C-S bond formations. From these effective applications, the unique stability and reactivity of TA-Au will be studied and explained, which is the reason and value of TA-Au discovery.
In second part, gold(I/III) redox catalysis will be presented through two application examples: cross-coupling of terminal alkynes, multiple bond di-functionalization. The most challenging part for coupling reactions is the competition between homo-coupling and cross-coupling products, while in our project, we have successfully developed a new method to selectively obtain cross-coupling as major product to homo-coupling product (ratio 12:1). Later on, we found a new method to achieve gold (I/III) redox cycle by using mild oxidant diazonium salt instead of PIDA or Selectfluor strong oxidant. The new mild and efficient method have largely extended the application of gold(I/III) redox catalysis into organic synthesis.
In sum, the new gold catalysts and catalysis methods reported here are important to the development of gold catalysis field, which are critical and useful to help people understand the reason of applying noble gold species as catalysts, and the advantages that other metals do not have.
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Zhang, Min. "Study on selective carbon-carbon, carbon-nitrogen, and carbon-oxygen bonds formation starting from alkynes." Rennes 1, 2009. http://www.theses.fr/2009REN1S036.
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The thesis is composed of two parts. Part I presents catalytic C-C, C-N, C-O bond formation: a series of dienylethers, 2,5-disubstituted furans, allylketones, γ-functionalized ketones, multisubstituted quinolines were made starting from terminal alkynes with the initial help of a ruthenium catalyst. Part II presents C-C, C-N, C-O bond formation reactions: a variety of tetrahydropyrimidines, and 1,3-oxazines were synthesized starting from electron-deficient alkynes via multiple component reactionsLa thèse est composée de deux parties. La partie I présente la formation catalytique de liaisons C-C, C-N et C-O : une série d’ethers, de diényle, furanes 2,5-disubstitués, cétones allyliques et γ-fonctionalisées et quinolines polysubstituées ont été préparées à partir d’alcynes avec l’aide initiale d’un catalyseur de ruthenium. La partie II présente la formation de liaisons C-C, C-N, C-O: une variété de tetrahydropyridines, et de 1,3-oxazines ont été synthétisées à partir d’alcynes electrophiles via des réactions à composants multiples
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Allpress, Caleb J. "Oxidative Aliphatic Carbon-Carbon Bond Cleavage Reactions." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/2003.
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The work presented in this dissertation has focused on synthesizing complexes of relevance to dioxygenase enzymes that oxidatively cleave aliphatic carbon-carbon bonds. The goal of this research was to elucidate mechanistic aspects of the activation of aliphatic carbon-carbon bonds towards cleavage by reaction with oxygen, and also investigate the regioselectivity of these reactions. The oxidative cleavage of a variety of enolizable substrates has been explored by utilizing several transition metal complexes supported by an aryl-appended tris(pyridylmethyl)amine ligand.
In order to probe the widely-accepted “chelate hypothesis” for how changes in regiospecificity are achieved as a function of metal ion, we synthesized the compound [(6Ph2TPA)Fe(PhC(O)COHC(O)Ph)]OTf. Based on UV-vis and IR spectroscopy, the acireductone enolate was found to bind via a six-membered chelate ring. By comparison with the reactivity of [(6Ph2TPA)Ni(PhC(O)COHC(O)Ph)]ClO4, we determined that the chelate hypothesis was an insufficient explanation of the observed regioselectivity. Rather, ferrous ion-mediated hydration of a vicinal triketone intermediate was the key factor in determining the regioselectivity of the C-C cleavage reaction.
We have developed a high-yielding synthetic route to protected precursors of C(1)H acireductones. Preparation of the complexes [(6Ph2TPA)M(PhC(O)COCHOC(O)CH3)]ClO4 (M = Fe, Ni) followed by judicious choice of deprotecting conditions allowed us to investigate the oxygen reactivity of a mono-nuclear complex with a dianionic acireductone substrate for the first time. This provides a promising strategy to continue investigations of complexes of relevance to the enzyme- substrate adduct of the acireductone dioxygenases.
Divalent late first-row transition metal complexes have been used to investigate some new strategies for the activation of dioxygen and subsequent cleavage of C-C bonds. We have utilized photoreduction of a Ni(II) center to generate a highly O2-reactive Ni(I) fragment that leads to cleavage of a chloro-diketonate substrate. Additionally, we have found a Cu(II)-mediated thermal cleavage of chloro-diketonate substrates at room temperature. This reaction is interestingly accelerated by the addition of a catalytic amount of chloride ion.
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Dombrowski, James Michael. "Catalytic Cleavage of Carbon-Carbon Sigma Bonds Using Transition Metals." Thesis, Boston College, 2005. http://hdl.handle.net/2345/407.
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Thesis advisor: Lawrence T. ScottThe focus of this project was to probe the ability of various transition metal complexes to cleave carbon-carbon bonds in a C30H12 hemifullerene. The hemifullerene was synthesized in our lab from commercial 1-tetralone and bromonaphthalene in six steps. Palladium and nickel complexes were used to open the five membered rings along the periphery of the C30H12 bowl. Diphosphine complexes of nickel were capable of opening either all three five membered rings or one of the periphery five membered rings and the central six membered ring
Thesis (BS) — Boston College, 2005
Submitted to: Boston College. College of Arts and Sciences
Discipline: Chemistry
Discipline: College Honors Program
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Liu, Yang <1988>. "Ni(II) and Photocatalyzed Functionalization of Carbon-Carbon Double Bonds." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9360/1/PhD%20Thesis_MB_%20Yang_Liu%20.pdf.
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Homogenous nickel catalysis is gaining more and more attention of chemist due to a variety of oxidative states resulting from distribution of its external electron in 3d orbital and abundance in the earth crust. Due to difference in diameter and distribution of external electron, nickel complexes possess some unique activities that 4d, 5d noble metals can’t achieve.
In this thesis, we described our work on nickel(II) catalyzed Suzuki coupling of electron perturbed allenes to synthesize stereochemically defined enamine and ester. The methodology showed excellent tolerance to variously substituted phenylboronic acids. Additionally, with allenamide, it can also proceed in cascade tricomponent versions with aldehyde wherein dimethylzinc was also compatible. Theoretical computation was conducted to reveal the nature of mechanism. This work realized an umpolung of nucleophilicity of allenamde, extending the reactivity of it.
As an expansion of previous work on nickel chemistry, we stretched our sight to photoredox reaction with initial idea of using organonickel as co-catalyst. So, we devoted to develop photocatalyzed synthesis of 1,3,4-trisubstituted pyrrole in a mild, oxidant-free way which was also documented in this thesis. Further work to disclose the mechanism were also done suggesting the azide were reduced through a new pathway.
Wacker oxidation is a quite useful transformation from alkene to ketone or aldehyde which always needs palladium catalyst system and theoretically at least one equivalent oxidant. Herein, we disclose a new way to realize Wacker Oxidation through a gentle photoredox process where noble metal, harsh condition, oxidant or other additives are not indispensable any more.
At last, the assistant work has been done to realize the Cp*Rh(III) catalyzed enantioselective C-H activation of acrylamide which is not further mentioned in this thesis. In this work, the activated acrylamide coupled with terminal allene affording an annulated 5-member lactam with excellent enantioselectivity. (DOI: 10.1002/anie.201909971)
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O'Connor, Ryan. "Rhodium-catalysed allylic substitution with unstabilised carbon nucleophiles : asymmetric construction of carbon-carbon bonds." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/17253/.
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The controlled formation of carbon-carbon bonds is the bedrock of organic chemistry, with the asymmetric construction of stereogenic carbon-carbon bonds remaining a key motivation for the development of novel synthetic methodologies. Transition metal catalysis provides an important strategy in the arsenal of the modern synthetic chemist. While there is a plethora of transition metal-catalysed cross-couplings for the formation of sp2-sp2 and achiral sp2-sp3 carbon bonds, there are relatively few methodologies for the selective formation of stereogenic sp-sp3, sp2-sp3 and sp3-sp3 carbon-carbon bonds, the number of which that involve highly reactive organometallic reagents are fewer still. Two methodologies that can enable this asymmetric coupling are copper-catalysed SN2’ allylic alkylation and transition metal-catalysed allylic substitution. The overall utility of both these methods is described in the introductory review, which seeks to compare and contrast the relative advantages and disadvantage of both approaches. The asymmetric formation of carbon-carbon bonds utilising unstabilised carbon nucleophiles is generally dominated by the copper-catalysed SN2’ allylic alkylation. However, the copper-catalysed reaction suffers from poor substrate scope, in which electronically biased or symmetrical substrates are required in order to ensure favourable regioselectivities. Another restriction is that, for the formation of a stereocenter, the reaction is mechanistically limited to disubstituted allylic substrates. These linear substrates often require a multistep synthesis which involves a selective olefination, as an isomeric mixture of alkenes would result in the erosion of asymmetric induction. In contrast, there has been very little development of the analogous transition metal-catalysed allylic substitution utilising unstabilised carbon nucleophiles, especially in comparison to the analogous methodologies utilising stabilised carbon and heteroatom nucleophiles. Despite the numerous potential advantages that are afforded by this approach, a general method for the regio- and stereoselective transition-metal catalysed allylic substitution utilising unstabilised carbon nucleophiles has yet to be reported. Chapter 2 describes the development of a novel regio- and stereoselective rhodium-catalysed allylic substitution reaction, which utilises benzyl magnesium bromide as an unstabilised carbon nucleophile. Following a brief introduction to the rhodium-catalysed allylic substitution reaction, this chapter is organised into four distinct sections. The first of these outlines the identification of a suitable nucleophile, and the subsequent development of reaction conditions for the regioselective alkylation of secondary allylic carbonates with a range of benzyl magnesium bromides transmetallated with zinc iodide. Then the next section will deal with studies toward the development of the stereospecific variant, these studies will highlight the main challenges of deploying a sp3-hybridised carbon nucleophile. This section will also determine the absolute stereochemical outcome of the reaction, thus confirming the inner sphere mechanism of the reaction. The third section will demonstrate that how the limitation of the stereospecific reaction, namely the fluxionality of the rhodium-enyl, can be utilised to develop a regio- and diastereoselective alkylation for the formation of 1,2-stereoarrays containing tertiary and quaternary carbon stereocenters. Finally, preliminary studies towards the expansion of this methodology to include an sp2-hybridised vinylic nucleophiles for the preparation of 1,4-skipped dienes will be detailed. Overall, we have developed a novel, highly regioselective rhodium-catalysed allylic substitution of secondary allylic carbonates utilising highly unstabilised carbon nucleophiles. We also have developed a highly diastereoselective allylic substitution for the construction of both tertiary and quaternary carbon stereocenters, which to best of our knowledge, has yet to be described in the context of rhodium-catalysed allylic substitution utilising an unstabilised carbon nucleophile. We have successfully carried out preliminary studies towards the development of a rhodium-catalysed allylic substitution utilising a vinyl organometallic reagent as nucleophile, as well.
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Fernandez, Gimenez Marta. "Iridium-catalysed cleavage and formation of unstrained aliphatic carbon-carbon bonds." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3018330/.
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McGuinn, John Stephen. "Rhodotorula rubra CBS 6469 mediated reduction of carbon-carbon double bonds." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/11126.
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A range of compounds designed around a template based upon (Z)-5-benzylidene thiazolidine-2,4-dione were synthesised by Knoevenagel condensation. These were screened against Rhodotorula rubra CBS 6469, a red yeast, using a modification of a process developed by SmithKline Beecham. This has allowed the construction of a 'map' defining the structural features of the template which are required to afford reduction of the carbon-carbon double bond. It has been shown that X1 and X2 must be S and O respectively whilst R3 can be methyl or benzyl. Alkyl substitution at R2 is not tolerated but a variety of substituents can be present at R1. Para groups can be accommodated at R1, but only methyl in the alkyl series, as well as the meta methoxy group. It has also been shown that replacement of the phenyl ring with a cyclohexyl moiety still allows reduction to take place. (Fig. 10893A). Relative reaction rates are also discussed along with the development of a process to afford reduction using Rhodotorula rubra CBS 6469 immobilised in calcium alginate beads. By carrying out reductions on deuterated compounds, and in deuterated media, steps have been taken towards the elucidation of the mechanism of reduction. The following scheme is proposed as a possible mechanistic pathway.
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Tani, Yosuke. "Catalytic Addition of Functionalities across Carbon-Carbon Multiple Bonds with Carbon Dioxide and Related Electrophiles." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199321.
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Hare, P. M. "Studies concerning carbon-hydrogen-metal bonds." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370264.
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Kelly, Eugene John. "Catalytic activation of carbon-hydrogen bonds." Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333819.
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Kunchithapatham, Kamala. "Development of Calcium and Palladium Catalysts for the Formation of Carbon-Carbon and Carbon-Heteroatom Bonds." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337955731.
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ZAGHI, ANNA. "Batch and continuous-flow synthetic processes for the formation of carbon-carbon and carbon-heteroatom bonds." Doctoral thesis, Università degli studi di Ferrara, 2017. http://hdl.handle.net/11392/2488074.
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L’organocatalisi è un ramo della catalisi che utilizza piccole molecole organiche per promuovere trasformazioni chimiche in cui si ha la formazione di nuovi legami carbonio-carbonio e/o carbonio-eteroatomo. L’impiego di questa metodologia può offrire numerosi vantaggi: gli organocatalizzatori, infatti, sono in grado di operare in condizioni blande, anche in mezzi acquosi, senza richiedere l’utilizzo di metalli di transizione. Quest’ultima caratteristica risulta particolarmente favorevole nel caso della sintesi di composti che non tollerano contaminazione da parte di metalli come i prodotti di interesse farmaceutico e, più in generale, i composti ad attività biologica. Inoltre, gli organocatalizzatori hanno generalmente basso costo e sono facilmente reperibili.
La chimica in flusso continuo rappresenta una valida alternativa a quella in condizioni batch grazie ai numerosi vantaggi che derivano sia dalla natura del processo in continuo che dalla piccola dimensione dei canali nei quali avviene la reazione chimica. Tra i possibili benefici si possono ricordare la riduzione dei rischi, la sostenibilità, la facilità di scale-up e la semplicità di automazione/monitoraggio dei normali parametri di reazione (velocità di flusso, temperatura, pressione e stechiometria di reazione).
Alcuni svantaggi tipici dell’organocatalisi, come il riciclo dell’organocatalizzatore e l’alto loading spesso necessario per certe trasformazioni, possono essere superati grazie all’eterogeneizzazione degli stessi organocatalizzatori. Questa permette di applicare una procedura in flusso continuo in maniera efficace arrivando a raggiungere alti livelli di stereoselettività e di produttività.
La maggior parte degli studi riportati in letteratura riguardanti la sintesi asimmetrica in flusso continuo utilizza catalizzatori supportati su materiale polimerico o su particelle inorganiche, che costituiscono il letto fisso all’interno di macro- o microreattori.
In questa tesi sono riportate metodologie batch ed in flusso continuo per la formazione di legami carbonio-carbonio e carbonio-eteroatomo, promosse da organocatalizzatori che agiscono attraverso una catalisi via enammina o ione imminio, oppure sfruttando la reattività di umpolung.Organocatalyzed reactions in which organic molecules catalyze single or multiple chemical transformations were found to be an efficient synthetic tool for creating various carbon-carbon and carbon-heteroatom bonds throughout the synthesis of a wide range of achiral and chiral acyclic as well as cyclic derivatives. The benefits of organocatalytic reactions include the use of inexpensive and readily available organic compounds as catalysts, as well as increased synthetic efficiency as no metal traces have to be removed at the end of the processes. This last feature is particularly suited to the preparation of biologically relevant compounds that do not tolerate contamination. The continuous-flow approach has recently emerged in the organic chemistry community as an interesting and alternative method to batch processing for performing chemical transformations. This technology has a number of attractive advantages that are related both to the nature of the continuous process and to the small size of the channels in which the reactions occur. These include (i) large surface to volume ratios and enhanced mixing quality; (ii) superior mass and heat transfer and, hence, improved operational safety; (iii) good real-time reaction monitoring by incorporating in-line analytical devices, allowing fast reaction screening and optimization; (iv) improved scalability. Typical drawbacks of organocatalysis such as organocatalyst recycling and the high catalyst loading often required for several transformations may be overcome by the heterogeneization of organocatalysts that allows the set-up of effective continuous-flow procedures endowed with high levels of stereoselectivity and productivity. The majority of the reported studies on asymmetric flow organocatalysis utilize the active catalyst immobilized on either polymeric or inorganic particles as packing material of macro- and micro-reactors. In this thesis are reported batch and continuous-flow synthetic approaches for the formation of carbon-carbon and carbon-heteroatom bonds, mediated by organocatalysts acting via enamine and iminium catalysis, and umpolung reactivity.
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Wen, Ting Bin. "Alkyne activation and carbon-carbon bond formation mediated by osmium complexes /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202003%20WEN.
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Bronk, Brian Scott 1967. "New methods for the formation of carbon-carbon bonds via organometallic compounds." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/35441.
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Maggiotti, Virginie. "Direct biocatalytic asymmetric aldol reactions." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275468.
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Yam, Man Sheung Mandy. "Addition polymerization of phosphorus-carbon double bonds." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/5751.
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The distillation of phosphaalkene MesP=CPh 2(I, Mes = 2,4,6-trimethyiphenyl) has
afforded poly(methylenephosphine) (II) in the residue with a molecular weight of ca. 30,000
gmo1−¹. Polymer II can also be obtained using radical and anionic initiators. The backbone of
polymer II consists of phosphine moieties which can be chemically functionalized using
hydrogen peroxide and elemental sulfur to afford air-stable polymers [-MesP(=O)CPh₂₋] and
[-MesP(=S)CPh₂₋],respectively. The thermogravimetric analyses (TGA) of these polymers
showed a high thermal stability to weight loss (Tonset = ca. 300 °C).
Using the base-catalyzed phospha-Peterson reaction, we have synthesized several P-Mes
phosphaalkenes including MesP=C(4-FC ₆H₄)₂(III), Me5PCPh(4-FC₆H₄)(IV), MesPC(4-
MeOC₆H₄)₂(V), MesP=CPh(4MeOC₆H₄)(VI), and MesPCPh(2-pyridyl) (VII). X-ray quality
crystals were obtained for phosphaalkenes III, VI, and VII. Attempts to prepare P-adamantyl (P
Ad) phosphaalkenes with this method were unsuccessful. In an attempt to prepare AdPCPh ₂,
the product isolated was found to be a 1 ,2-diphosphetane (AdPCPh₂)₂ by X-ray crystallography.
The effects of reaction temperature, residence time, and initiator loading on the radical
polymerization of I were studied. The polymerization conditions of 1% VAZO 88 initiator [1,1’-
azobis(cyclohexanecarbonitrile)] at 100 °C for 24 hours are shown to give a higher molecular
weight (M = ca. 16,000 gmo1−¹) and yield for II for radical polymerizations. Employing these
conditions, phosphaalkenes Ill—WI were polymerized to give C-functionalized
poly(methylenephosphine)s with molecular weight in the range of 6,000 to 20,000 gmo1−¹.
The radical copolymerization of phosphaalkenes with styrene offers a convenient route to
incorporate phosphine moieties into organic polymers. Preliminary estimation of the monomer
reactivity ratios for phosphaalkene I and styrene was conducted using Fineman—Ross and
Kelen-Tudos methods (rpA ≈ 2 and rsT ≈ 1). This study suggests that this copolymer may consist of
poly(methylenephosphine) sequences, randomly, distributed between styrene moieties.
To expand the addition polymerization to other PC systems, several new P-fluoroaryl
phosphaalkenes were prepared using base-induced 1,3-hydrogen rearrangement. Employing 2,6-
bis- or 2,4,6-tris-(trifluoromethyl)phenyl (ArF’ and ArF) substituents, the rearrangement reaction
becomes a viable route to isolable phosphaalkenes with a C-methyl substituent (i.e.,
ArF’P=CMe₂, ArF’P=CMePh, and ArP=CMe₂).
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Dinsdale, Nicola. "New approaches to phosphorus-carbon multiple bonds." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443692.
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佐藤, 章徳. "Studies on Free Radical Reactions to Form Carbon-Phosphorus and Carbon-Sulfur Bonds." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/78026.
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Kyoto University (京都大学)0048
新制・課程博士
博士(工学)
甲第14582号
工博第3050号
新制||工||1454(附属図書館)
26934
UT51-2009-D294
京都大学大学院工学研究科材料化学専攻
(主査)教授 大嶌 幸一郎, 教授 檜山 爲次郎, 教授 松原 誠二郎
学位規則第4条第1項該当
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Yoo, Woo-Jin. "Copper-catalyzed coupling reactions using carbon-hydrogen bonds." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95566.
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The development of efficient strategies towards the formation of carboncarbon (C-C) bonds is of great interest. A common route into C-C bond formation occurs through the coupling between nucleophiles and electrophiles. However, in most cases, these activated coupling partners are often derived from less reactive starting materials. The direct use of carbon-hydrogen (C-H) bonds to form C-C bonds1.2 would be highly desirable since it would eliminate preactivation of the substrate and improve the overall efficiencies in synthetic routes by removing needless synthetic steps (Figure 1).Cette thèse est une investigation sur l'utilisation des liaisons carbonehydrogene (C-H) en tant que substrats dans les procèdes de formation de liaisons carbone-carbone et carbone-heteroatome. Dans la première partie de cette thèse, une réaction de couplage oxydant est décrite entre la liaison C-H adjacent à l'atome d’oxygène d'éthers cycliques benzyliques et la liaison C-H de malonates. Ce procède, utilisant I' oxygène comme oxydant terminal, est catalyse par un mélange de trois catalyseurs: le triflate de cuivre (Il), le chlorure d'indium (Ill), et le N-hydroxyphthalimide. Dans la deuxième partie de cette thèse, une série de réactions de couplages oxydants est décrit entre des liaisons C-H acyles et une variété d'hétéroatomes nucléophiles tel qu'enoles, alcools, et amines pour la synthèse d'esters et d'amides. Cette méthode emploie l'hydropéroxide de tert-butyle comme oxydant, ce dernier étant active par une quantité catalytique de sel de cuivre. Dans la troisième et dernière partie de cette thèse, une réaction de couplage multicomposants entre alcynes, aldéhydes, amines et dioxyde de carbone à pression atmosphérique, est présentée. Cette catalyse au cuivre procède via une réaction tandem A3-coupling/cyclisation-carboxylation pour la synthèse simple et efficace d'oxazolidines.
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O'Hare, D. M. "Activation of carbon hydrogen bonds by metal atoms." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355789.
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Duffy, Lorna A. "From spirocyclisations to ring-size selective reductions : the effect of co-solvent on the chemistry of SMI₂." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496693.
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Stichbury, Joanne Clare. "The oxidation of dimolybdenum complexes containing metal carbon bonds." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627595.
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Nelson, Amanda Kay. "Metal-Catalyzed Formation and Transformations of Carbon-Boron Bonds." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/83400.
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Our research seeks new methods for functionalizing organic small molecules using organoboronic derivatives as a versatile handle for late-stage manipulations. Metal-catalyzed formation of new carbon-boron bonds and their subsequent transformations are highlighted.
Among the myriad of unsaturated substrates for conducting borylation reactions, allenes have received minimal attention. These substrates are uniquely advantageous given that diboration results in the formation of both allylic and vinylic boronates. Orthogonal reactivity of the sp2 and the sp3 C-B bonds can allow for chemoselective transformations. However, oxidation of the carbon-boron bond is one example in which the conditions are unselective. To address this shortcoming, a platinum catalyst was developed for the diboration of 1,1-diaryl allenes with a differentially protected diboron reagent, pinB-Bdan. The reaction proceeds regioselectively in high yields to furnish olefins bearing a vinylic Bpin and an allylic Bdan moiety. The subsequent chemoselective transformation of each boron center was demonstrated.
Methods for preparing 1,8-diaminonaphthalene protected vinylboronates conjugated to carbonyl groups are severely limited. A simple and efficient protocol was developed for carrying out an environmentally friendly copper(II)-catalyzed beta-borylation of alkynoates and alkynamides in water and open-to-air. Following the discriminative activation of the more Lewis acidic pinacol protected boron center in pinB-Bdan, a regio-, stereo- and chemoselective beta-borylation of acetylenic substrates delivers (Z)-beta-boryl enoates and primary, secondary, and tertiary enamides under very mild conditions.
As an inexpensive and earth abundant metal, catalysts based on copper are highly desirable. An international collaborative project to develop a copper-catalyzed cross-coupling reaction of beta-boryl carbonyl compounds was explored. Preliminary results found these substrates to be either unstable towards or unreactive under the reactions conditions screened.Ph. D.
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Kirkham, Matthew Samuel. "Activation of carbon-fluorine bonds using ruthenium dihydride complexes." Thesis, University of Bath, 2001. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340990.
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Stafford, Carolyne. "The sequential insertion of carbon monoxide and imines into nickel-carbon sigma-bonds and kinetic analysis of imine insertion into palladium-acyl sigma-bonds." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18447.
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ABSTRACT The Sequential Insertion of Carbon Monoxide and Imines into Nickel-Carbon Sigma-Bonds and Kinetic Analysis of Imine Insertion into Palladium-Acyl Sigma-Bonds The coupling of imines and carbon monoxide mediated by late transition metals has been previously reported in the Arndtsen laboratory. The fundamental properties of 2,1-migratory insertion of imines into nickel- and palladium-acyl bonds are presented in this text. This study investigates the use of neutral eta2-N,O-salicylaldiminato nickel (II) systems (Chapter 2) as potential complexes to mediate the sequential insertion of carbon monoxide and imines. These complexes undergo rapid carbon monoxide insertion. Subsequent imine insertion is permitted when the imine substrate is sterically unencumbered. The coupling product disproportionates leading to the formation of 1,2-diamides. In our laboratory, kinetic and thermodynamic studies on the coordination and 2,1-migratory insertion of imines into palladium-carbon sigma-bonds were the focus of former student Rania Dghaym, Ph.D. Chapter 3 completes these studies, and offers a mechanistic picture of the pathway by which 2,1-migratory insertion into palladium-acyl bonds proceeds. Our mechanistic data suggest that imine insertion is distinct from olefin insertion and involves the concerted migratory attack of the sigma-coordinated imine to the electrophilic acyl ligand.RÉSUMÉ L'insertion séquentielle de monoxyde de carbone et d'imines dans des liens sigma nickel-carbone ainsi que l'analyse cinétique de l'insertion d'imines dans le lien palladium-acétyle Le couplage d'imines et de monoxyde de carbone médié par des métaux de transition a été récemment publié par le laboratoire du Professeur Arndtsen. Les propriétés fondamentales de l'insertion migratoire-2,1 d'imines dans les liens nickel- et palladium-acétyle sont présentées dans le texte ci-présent. Les complexes neutres eta2-N,O-salicylaldiminato de nickel (II) sont le sujet de recherche dans le chapitre 2 pour leur potentiel de médier l'insertion séquentielle de monoxyde de carbone et d'imine. L'insertion de monoxyde de carbone dans le lien nickel-méthyle est rapide. Par contre, l'insertion d'imine subséquente est seulement observée dans les cas où l'encombrement stérique de celle-ci est minime. Le produit du couplage mène à la formation de 1,2-diamides. Dans notre laboratoire, la cinétique et thermodynamique de l'insertion migratoire-2,1 dans les liens sigma palladium-carbone était le sujet d'étude de Rania Dghaym, Ph.D., une étudiante précédente du laboratoire. Au chapitre 3 nous présentons la suite de ses études et offrons un portrait global du mécanisme par lequel l'insertion migratoire-2,1 dans les liens palladium-acétyle se produit. Nos résultats suggèrent que le mécanisme d'insertion d'imines est distinct de celui d'insertion d'oléfines et implique une attaque migratoire concertée de l'imine sigma-coordonnée au ligand acétyle électrophilique.
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Jayatissa, Kuruppu Lilanthi. "A Metal-Free Approach to Biaryl Compounds: Carbon-Carbon Bond Formation from Diaryliodonium Salts and Aryl Triolborates." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2229.
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Biaryl moieties are important structural motifs in many industries, including pharmaceutical, agrochemical, energy and technology. The development of novel and efficient methods to synthesize these carbon-carbon bonds is at the forefront of synthetic methodology. Since Ullmann’s first report of stoichiometric Cu-mediated homo-coupling of aryl halides, there has been a dramatic evolution in transition metal catalyzed biaryl cross-coupling reactions.
Our work focuses on the discovery and development of an unprecedented reagent combination for metal-free cross-coupling. It is hypothesized that direct carbon-carbon bond formation occurs via a triaryl-λ3-iodane and that electrophile/nucleophile pairing is critical for success in the reaction. Proof-of-concept for this approach focused on the reaction between bromo 4-trifluoromethylphenyl (trimethoxybenzene)-λ3-iodane and potassium 3-fluorophenyltriolborate. The spectator ligand and counter ions are important parameters for both reactivity and selectivity of the aryl group transfer in this reaction. Moderate to good yields of biaryl products are obtained by this method. Experimental evidence supports the assertion of a metal-free cross-coupling reaction.
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Taylor, Jason Guy. "Development of catalysts for the addition of N-H and O-H to carbon-carbon double bonds." Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/1350.
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The addition of O-H and N-H bonds across carbon-carbon double bonds offers a direct way of synthesising a variety of organic molecules. These reactions have attracted considerable interest in academic research and the chemical/pharmaceutical industry in recent years due to its atom economy. Nevertheless, there remains a considerably challenge to control the regioselectivity and the stereoselectivity of this reaction. This PhD thesis describes the investigation into the discovery and development of a general method for catalytic hydroamination (HA), hydroalkoxylation and hydrooxyacylation of olefins. Air- and moisture-stable transition metal catalysts were the main focus of this study. The introductory Chapter provides an overview of recent advances in N-H addition reactions involving late transition metal catalysts. In Chapter 2, rhodium and ruthenium complexes were examined as catalysts for the addition of N-H bonds to alkenes. The combination of (RuCl2)n/dppb/AgOTf generated a catalyst effective for the addition of methyl carbamate to norbornene in a modest yield. Copper (II) trifluoromethanesulfonate was discovered to be an efficient catalyst for the addition of carboxylic acids, phenols and alcohols to norbornene. A selection of norbornyl esters and ethers were formed in good to excellent yields. In the following Chapter, the combination of copper (II) trifluoromethanesulfonate and diphosphine ligands was successfully applied to the addition of sulfonamides and carbamates to vinylarenes, 1,3-dienes and norbornene in good to excellent yields. In Chapter 4, the intramolecular hydroamination reaction was developed. The synthesis of several acyclic precursors were described, along with attempts to cyclise them. The chapter ends with the attempted synthesis of tricyclic molecules using a palladium-catalysed methodology. The last Chapter contains experimental procedures and characterisation data of all the compounds synthesised during the course of this project.
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Lacy, Adam. "Investigation of methods for the formation of nitrogen-carbon bonds." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543021.
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Dghaym, Rania. "The novel sequential insertion of carbon monoxide and imines into palladium-carbon [sigma]-bonds : synthesis, mechanism and reactivity." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36803.
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The development of non-amino acid routes for the construction of peptides remains a challenge. The main goal of this study is to develop a new transition metal-mediated route to synthesize alpha-amino acid and peptide derivatives from imines and carbon monoxide. The proposed approach requires the sequential insertion of CO and imine into late transition metal sigma-bonds.In Chapters 2 and 3, the ability of the palladium complex L2Pd(CH 3)N(R)=C(H)R'+ X- [L2 = chelating nitrogen ligands, X- = non-coordinating counteranion] to mediate the insertion of imines is examined. While L 2Pd(CH3)N(R)=C(H)R'+ X- is inert towards imine insertion into a palladium-methyl bond, the addition of CO to L2Pd(CH3)N(R)=C(H)R '+ X- yields the palladium-acyl complex L2Pd(COCH3)N(R)=C(H)R' +X-, which subsequently reacts to form the novel product of imine insertion: (L2)Pd[eta2-CH(R ')NRCOCH3]+X-. This demonstrates that these palladium complexes can undergo the novel sequential insertion of carbon monoxide and imine into the palladium-carbon bond in a manner directly analogous to that observed in olefin/CO alternating co-polymerizations. Examination of the mechanism of imine insertion (Chapter 3) demonstrates that, unlike olefins, imines undergo a concerted migration from the sigma-imine complex to form the product of imine insertion. The X-ray structure of the insertion complex 2.6b suggests the unique combination of amide bond formation, carbonyl oxygen chelation, and resonance stabilization of the chelate ring provides the stabilization required for this reaction to occur.
The product of CO/imine insertion is found to be inert towards reaction with carbon monoxide (Chapter 4). However, the addition of CO to its chloride analogue, generated via the oxidative addition of N-acyl iminium salts Tol(H)C=N(CH 2Ph)COPh+Cl- to Pd2(dba) 3•CHCl3 in the presence of 2,2'-bipyridine, results in the formation of 2-imidazolinecarboxylate derivatives (Chapter 5). Mechanistic studies reveal that imidazoline formation occurs via CO insertion into Pd--C bond of (bipy)Pd[eta2-CH(R' )NRCOR″]+Cl-, generating a palladium-bound alpha-amino acid derivative, which is followed by coupling with imine. This reaction is extended into a novel one pot palladium-catalyzed coupling of imine, carbon monoxide and acid chloride into 2-imidazolinecarboxylate derivatives. The described methodology provides a facile route to access the biologically relevant imidazoline derivatives through the sequential insertion of CO and imine into palladium-alkyl bonds.
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Markopoulos, Georgios [Verfasser], and Henning [Akademischer Betreuer] Hopf. "A New Synthesis of Tribenzotriquinacene and the Rigidity of Carbon-Carbon Single Bonds / Georgios Markopoulos ; Betreuer: Henning Hopf." Braunschweig : Technische Universität Braunschweig, 2013. http://d-nb.info/1175822949/34.
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Uang, Shinian. "Preparation and Stereochemistry of Reactive Intermediates Containing a Silicon-Carbon Double Bond." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc277928/.
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1,1-Dimethyl-2-neopentylsilene reacted with the N-methylimine of benzophenone to give 1,2,2-trimethyl-3- neopentyl-4,4-diphenyl-l-aza-2-silacyclobutane, I, and 2,3,4,4a-tetrahydro-2,3,3-trimethyl-1-phenyl-4-neopentyl-2- aza-3-silanephthalene, II, in 35% and 20% yields, respectively. Compounds I and II did not serve as thermal silene precursors. Heating I and II to over 280°C did not yield 1,3-disilacyclobutanes. In the presence of 2,3- dimethyl-1,3-butadiene typical silene products were not obtained. However, I and II reacted rapidly with methanol at room temperature to give the ring-opened products (E)-2- methoxy-2,5,5-trimethyl-2-silahex-3-ene, III, 1,1- diphenyldimethylamine, IV, and 2-methoxy-2,5,5-trimethyl-3- (N-methylaminodiphenyl) methyl-2-silahexane, V.
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Washington, Marlena Patrice. "Investigations of Opto-Electronically Interesting Materials Featuring Phosphorus-Carbon Double Bonds." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1278691072.
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Buquoi, John Q. III. "Multicomponent Radical Reactions Incorporating Heteroatom-Carbon Bonds Via Polarity-Reversal Cascades." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574348050305556.
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Davis, Jason L. "The sequential insertion of carbon monoxide and imines into nickel-carbon [sigma]-bonds : synthesis, reactivity and multi-component couplings." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85901.
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The development of new methods of generating alpha-amino acid derivatives via multi-component reactions remains an important challenge. The primary goal of this study is to develop new transition metal-mediated routes to synthesize these alpha-amino acid derivatives using combinations of simple reagents, such as imines, carbon monoxide, acid chlorides and organotin reagents. The proposed approach requires the sequential insertion of imine and carbon monoxide into late transition-metal sigma-bonds, as well as the further reactivity of the products.In chapter 2, the ability of the nickel complex L2Ni(CH 3)N(R)=C(H)R'+X- (L2 = chelating nitrogen ligands, X- = non-coordinating counteranion) to mediate the insertion of imines is examined. Although L2Ni(CH3)N(R)=C(H)R' +X- does not undergo direct imine insertion into the Ni-CH3 bond, the addition of CO leads to the generation of the novel nickel complex (L2)Ni[n2-CH(R')NRCOCH 3]+X- via the insertion of imine into the nickel-acyl bond of L2Ni(COCH3)N(R)=C(H)R' +X-. This demonstrates as proof of concept, that these nickel complexes can mediate the sequential insertion of CO and imine into nickel-methyl bonds, in direct analogy to well known CO/olefin insertions. Further reactivity studies have demonstrated that the amide bound nickel chelates generated via the sequential insertion of CO and imines are generally inert towards subsequent migratory insertion with CO, imine and olefins (Chapter 3). These complexes are also inert towards auxiliary ligand exchange or amide de-chelation, with both mono- and bidenate nitrogen and phosphine ligands.
Studies involving the use of imines and alkenes as interchangeable insertion substrates, (Chapter 4) resulted in the first example of a metal mediated cyclocarbonylation incorporating imine as a formal insertion substrate. Based on these studies, one-pot sequential insertion cascade of CO, olefin, a second unit of CO, and imine was developed for the synthesis of 5 and 6 membered lactams. In addition, the competitive insertion propensity of imines and alpha-olefins was examined, and clear steric and electronic effects were identified.
The isoelectronic palladium-bound amide complexes, generated via the oxidative addition of N-acyl iminium salts (R(H)C=N(R')COR") to Pd2(dba) 3·CHCl3 can undergo a Stille-tye coupling with organotin reagents to generate alpha-substituted amide derivatives (Chapter 5). This reactivity was extended into a convenient and general one-pot synthesis of alpha-substituted amides and N-protected amines by a palladium-catalyzed three-component coupling of imines, acid chlorides or chloroformates, and organotin reagents. Mechanistically, this process provides an oxidative addition/reductive elimination-based alternative to nucleophilic approaches to C-C bond formation with imines, in which the imines are activated towards addition to palladium by RCOCl.
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Mohan, J. K. "Synthetic studies towards taxoids and reaction of diazoester with carbon-carbon /heteroatom bonds catalyzed by transition metal exchanged clay." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1998. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3408.
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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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Inami, Tasuku. "Studies on Nickel-Catalyzed Reactions via Alkyne Insertion into Carbon-Sulfur Bonds." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199274.
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Ke, Mingzhe. "Synthesis, characterization and reactivity of ruthenium porphyrin complexes containing metal-carbon bonds." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29126.
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The thesis describes developments in the organometallic chemistry of ruthenium porphyrin complexes, particularly their preparation, characterization and reactivity.
Treatment of paramagnetic Ru(rV)(porp)Br₂ species, prepared via the interaction of [Ru(porp)]₂ with HBr in CH₂CI₂, with organolithiums or Grignard reagents yields the corresponding diamagnetic Ru(IV) complexes Ru(porp)R₂, where porp = the 2,3,7,8,12,13,17,18-octaethylporphyrinato dianion(OEP): R = Ph, m-MeC₆H₄, p-MeC₆H₄, p-MeOC₆H₄, p-FC₆H₄, Me, Et; and porp = the 5,10,15,20-tetraphenylporphyrinato dianion(TPP): R = Ph. The spectral analyses (¹H NMR, UV/vis, and mass spectroscopies) of these complexes are fully consistent with the assigned structures, which are further verified by the X-ray crystallographical analyses of Ru(TPP)Br₂ and Ru(OEP)Ph₂. The dimethyl complex Ru(OEP)Me₂ is also formed along with Ru(OEP)(P[sup n]Bu₃)₂ by the reaction of Ru(III)(OEP)(P[sup n]Bu₃)Br and methyllithium, the process involving disproportionation of Ru(OEP)Me(P[sup n]Bu₃).
The diamagnetic nature of the Ru(porp)R₂ complexes, as evidenced by their sharp and temperature-independent ¹H NMR chemical shifts, requires that the d⁴-electrons of the Ru(IV) are spin-paired in the lowest, doubly degenerate d[sub xz] and d[sub]yz orbitals; the porphyrin ring current results in upfield shifts for the axial ligand protons with respect to their 'normal' positions. An unusual feature in the Ru(OEP)Ph₂ structure is the considerable distortion of the (Ph)C-Ru-C(Ph) fragment from linearity. The Ru(porp)R₂ complexes are stable as solids and in solution under atmospheric conditions, but the metal-carbon bonds are readily cleaved either by reagents such as protonic acids, carbon monoxide and phosphines, or via thermolysis. A CO insertion product Ru(OEP)Ph(COPh)
is observed in solution by ¹H NMR spectroscopy upon the reaction of Ru(OEP)Ph₂ with 1 atm CO in deuterated benzene at room temperature.
The anaerobic thermolysis of the Ru(porp)R₂ complexes at 80 - 100°C yields the five-coordinate, low-spin, paramagnetic Ru(porp)R derivatives, and organic products that depend on the nature of the aryl or alkyl moiety R and the solvent The remarkable transformations shown below have been demonstrated, and niechanisms are proposed.[See Thesis for Diagram] The Ru(OEP)Ph complex has been characterized crystallographically and, together with Ru(OEP)Ph₂, these represent the first reported structures involving organoruthenium porphyrins. The temperature-dependent *H NMR shifts for the Ru(OEP)R species establish a single spin state (S = 1/2) over the temperature range studied (-60° to 70°C).
Under appropriate conditions in benzene or toluene, the rate-(leternnning step for the thermal decomposition of the Ru(OEP)R₂ species (R = aryl) is the homolytic cleavage of the metal-carbon bond, and the temperature variation data for the rate constant of this step allow for an estimation of the Ru-C bond strength in solution. Such bond energies are critical for a better understanding of homogeneously catalyzed hydrocarbon reactions. Substitution effects on the Ru-aryl bond strengths were studied using four para- and meta-substituted phenyl complexes (p-Me, p-MeO, p-F, and m-Me); the bond energies are in the 29 - 33 kcal/mol range, and a Hammett ρ value of +1.7 describes the rate constant trend for the p-MeO, p-Me and unsubstituted phenyl systems.
Because of their ccordinatively unsaturated nature, the Ru(porp)R complexes are very reactive toward reagents. The Ru(OEP)Ph species readily binds a second axial ligand L, such as pyridine or tri-n-butylphosphine, to form a six-coordinate derivative, and temperature variation data for the equilibrium constant for pyridine binding give a solution bond energy of 11.2 kcal/mol for the Ru-N(py) bond. The Ru(OEP)Me species on reaction with L (py or P[sup n]Bu₃) undergoes disproportionation to Ru(OEP)Me₂ and Ru(OEP)L₂. The Ru(OEP)Ph species reacts with carbon monoxide to generate Ru(OEP)(CO)[sub n] (n = 1 or 2). Bromination of Ru(OEP)Ph forms a paramagnetic Ru(IV)(OEP)Ph(Br) intermediate, characterized by ¹H NMR, en route to Ru(OEP)Br₂, while treatment of Ru(OEP)Ph with HX (X = Br, CI) yields the Ru(OEP)X₂ species. Reaction of the Ru(OEP)(X-C₆H₄) complexes (X = H, p-MeO) with in situ-generated phenyl radicals is close to diffusion-controlled (k ≈ (1.4 - 2.0) X 10⁹ M⁻¹h⁻¹ at 60° - 100°C), and leads to the formation of the mixed aryl species Ru(OEP)Ph(p-MeOC₆H₄). Of interest, the photosensitized O₂-oxidation of Ru(porp)R species (R = aryl) yields the μ-oxo dinuclear species [Ru(porp)R]₂O, the metal-carbon bond remaining intact, which is unusual for the interaction of organometallic metalloporphyrins with dioxygen under light.Science, Faculty of
Chemistry, Department of
Graduate
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Zuideveld, Martin Alexander. "Solvolysis of palladium-carbon bonds in palladium(II) complexes containing diphosphine ligands." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2001. http://dare.uva.nl/document/60731.
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Lindsay, Maria. "Studies directed Towards the Iridium Catalyzed Synthesis of New Carbon-Nitrogen Bonds." ScholarWorks@UNO, 2017. http://scholarworks.uno.edu/td/2336.
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Amines are ubiquitous in nature and serve a variety of functions in living organisms. Because of this fact amines are of great biological and pharmaceutical interest. The iridium catalyst (pentamethylcyclopentadienyl) iridium dichloride dimer ([Cp*IrCl2]2) has been used in a number of ways to synthesize new carbon-nitrogen bonds. These studies were directed toward the development of a method for the iridium catalyzed N-alkylation of alpha-amino acid esters as well as the development of a strategy for synthesis of the natural product 275A.
We have optimized a method for the N-alkylation for alpha-amino acid esters. Using this method, we have N-alkylated a series of alpha-amino acid esters with a variety of alcohols. We have shown that the N-alkylation of the alpha-amino acid esters works consistently and gives the desired products in moderate to high yields. We have examined the effect of this method on the chiral center of the obtained products by analyzing their optical rotation. Evaluation of these specific rotations indicated racemization was occurring but it is believed that any loss of the chiral center is due to the reaction conditions.
Amphibian alkaloids are of great interest to the pharmaceutical and academic communities due to their biological activities. Unfortunately, they are not naturally available in large quantities which makes total synthesis the most common method of generating these compounds for evaluation. One amphibian alkaloid class of interest to us are the Lehmizidines. These are bicyclic ring structures consisting of a 7-member and 5-member ring with a nitrogen bridgehead. The alkaloid, 275A, was selected as a target for a general synthetic approach. This synthetic approach required the synthesis of novel diols. The construction of these diols along with a method for the synthesis of the azepane ring is presented here.
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Radomkit, Suttipol. "New Concepts, Catalysts, and Methods for Enantioselective Synthesis of C-B and C-C Bonds." Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:107272.
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Thesis advisor: Amir H. HoveydaChapter 1. Part A: N-Heterocyclic Carbenes Catalyzed Enantioselective Boryl Conjugate Additions to α,β-Unsaturated Ketones, Esters, Weinreb Amides and Aldehydes. The first broadly applicable enantioselective boryl conjugate addition reactions to a variety of α,β-unsaturated carbonyls are reported. Transformations are promoted by 5.0 mol % of a chiral Lewis basic N-heterocyclic carbene. The distinctive feature of the reactions in chemoselectivity of the method compared to the Cu-catalyzed variants has been illustrated. Part B: Enantioselective Synthesis of Boron-Substituted Quaternary Carbon Stereogenic Centers through N-Heterocyclic Carbenes Catalyzed Boryl Conjugate Additions to Cyclic and Acyclic Enones The first examples of Lewis base catalyzed enantioselective boryl conjugate additions that afford products containing boron-substituted quaternary carbon stereogenic centers are presented. The carbon–boron bond forming reactions are promoted by 1.0–5.0 mol % of a chiral N–hererocyclic carbene. Cyclic or linear α,β–unsaturated ketones can be used as suitable substrates and the desired products are obtained in 63–95% yield and 91:9 to >99:1 enantiomeric ratio. The utility of the Lewis base-catalyzed approach is demonstrated in the context of an enantioselective formal synthesis of antifungal natural product crassinervic acid. Chapter 2. Enantioselectivity Fluctuations in Phosphine–Cu-Catalyzed Enantioselective Boron-Allyl Addition to Aryl-Substituted Olefins. Catalytic enantioselective multicomponent processes involving B2(pin)2, aryl or heteroaryl monosubstituted olefins, and allylic phosphates or carbonates are disclosed. Transformations promoted by a chiral Cu–phosphine complex afford products that contain a primary C–B(pin) bond and an allyl-substituted tertiary carbon stereogenic center in up to 84% yield and 98:2 enantiomeric ratio. The utility of the approach is showcased in the enantioselective formal synthesis of biologically active heliespirones A and C. Based on mechanistic and computational studies, we show that enantioselectivities variations can depend on electronic and/or steric factors of the alkene substrate and the allyl electrophile as well as their concentration. In most cases, selectivity loss can be minimized and that the resulting insights are also applicable to reactions involving Cu–H species. Chapter 3. Synthesis of Vicinal Diboronate Compounds through Practical Phosphine–Copper Catalyzed Three-Component Processes. The phosphine–Cu-catalyzed multicomponent processes have been developed for a practical and direct synthesis of vicinal diboronate compounds. Reactions of alkenyl–boronates, allylic phosphates, and diboron reagents are promoted by 2.5–10 mol % of a Cy3P–Cu complex affording a wide range of desirable vicinal diboronate products. The ability for easy access to either regioisomers of the products with a C–B(pin) and an adjacent C–B(dan) bond that can be site-selectively functionalized is a noteworthy feature of the method
Thesis (PhD) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Claros, Casielles Miguel. "Development of Visible Light Photoredox Methodologies towards the Activation of Carbon-Halogen Bonds." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/669435.
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Metodologies fotocatalítiques sota irradiació de llum visible han estat desenvolupades amb diversos substrats disponibles al mercat com ara els àcids carboxílics, trifluoroboratos alquílics de potassi, silicats alquílics d'amoni o èsters activats entre d'altres. Sota irradiació de llum, aquests precursors s'activen mitjançant processos de transferència d'un sol electró amb catalitzadors fotoexcitables (PC). Entre ells, els halurs orgànics són socis d'acoblament convenients en la fotocatàlisi, ja que experimenten una escissió de l'enllaç C-halogen catalitzada per diversos PC en presència d'un donador d'electrons. Els clorurs de llogo no activats, que són fàcilment disponibles i matèries primeres estables, exhibeixen una inèrcia química inherent, en part, per les seves negatius potencials de reducció. Això va impedir el seu ús generalitzat com a precursors radicals en la fotocatàlisi de llum visible. En aquesta dissertació doctoral explorem l'ús d'un sistema catalític dual basat en metalls de la primera sèrie de transició (Cu, Co, Ni) per a l'activació d'aquests enllaços inerts C-Halogen. El disseny de l'catalitzador ha estat clau per desenvolupar una metodologia suau i general per a la reacció de desalogenación i la ciclació reductora intramolecular d'halurs d'alquil no activats amb alquens o alquins units. L'escissió de fortes enllaços Csp3-X està intervinguda per un intermedi de cobalt o níquel en baix estat d'oxidació altament nucleòfil generat per reducció fotocatalítica de llum visible que empra un fotosensibilitzador de coure.Metodologías fotocatalíticas bajo irradiación de luz visible han sido desarrolladas con varios sustratos disponibles en el mercado como por ejemplo los ácidos carboxílicos, trifluoroboratos alquílicos de potasio, silicatos alquílicos de amonio o ésteres activados entre otros. Bajo irradiación de luz, estos precursores se activan mediante procesos de transferencia de un solo electrón con catalizadores fotoexcitables (PC). Entre ellos, los haluros orgánicos son socios de acoplamiento convenientes en la fotocatálisis, ya que experimentan una escisión del enlace C-halógeno catalizada por varios PC en presencia de un dador de electrones. Los cloruros de alquilo no activados, que son fácilmente disponibles y materias primas estables, exhiben una inercia química inherente, en parte, debido a sus negativos potenciales de reducción. Esto impidió su uso generalizado como precursores radicales en la fotocatálisis de luz visible. En esta disertación doctoral exploramos el uso de un sistema catalítico dual basado en metales de la primera serie de transición (Cu, Co, Ni) para la activación de estos enlaces inertes C-Halógeno. El diseño del catalizador ha sido clave para desarrollar una metodología suave y general para la reacción de deshalogenación y la ciclación reductora intramolecular de haluros de alquilo no activados con alquenos o alquinos unidos. La escisión de fuertes enlaces Csp3-X está mediada por un intermedio de cobalto o níquel en bajo estado de oxidación altamente nucleófilo generado por reducción fotocatalítica de luz visible que emplea un fotosensibilizador de cobre.
Visible light photoredox Catalysis have been accomplished with several readily available bench-stable chemicals such as carboxylic acids, potassium alkyltrifluoroborates, ammonium alkyl silicates or redox-active esters among others. Under light irradiation, these precursors get activated by single-electron transfer processes with photoexcitable catalysts (PCs). Among them, organic halides are convenient coupling partners in photocatalysis since they undergo reductive C-halogen bond cleavage catalysed by several PCs in the presence of a sacrificial electron-donor. Non-activated alkyl chlorides, which are readily available and bench-stable feedstocks, exhibit an inherent chemical inertness, in part, due to their large negative reduction potentials. This precluded their widespread use as radical precursors in visible-light photocatalysis. In this doctoral dissertation we explored the use of a dual catalyst system based on first-row transition metals (Cu, Co, Ni) for the activation of these inert Carbon-Halogen bonds. Catalyst design has been key for developing a mild and general photoredox methodology for the dehydrodehalogenation reaction and the intramolecular reductive cyclization of non-activated alkyl halides with tethered alkenes or alkynes. The cleavage of strong Csp3-X bonds is mediated by a highly nucleophilic low-valent cobalt or nickel intermediate generated by visible-light photoredox reduction employing a copper photosensitizer
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Hung, Wai Yiu. "Syntheses and reactivities of osmium and ruthenium complexes with metal-carbon triple bonds /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202006%20HUNG.
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Bedford, Robin Bruce. "Group 9 metal catalysts for the homogeneous hydrogenation of carbon-nitrogen double bonds." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240524.
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Oliver, Andrew 1975. "The sequential insertion of carbon monoxide and non-linear optical chromophores into palladium-carbon bonds : a novel route to non-linear optical polyketones." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31283.
Full textAbstract:
This thesis presents a new approach to generating nonlinear optical side-chain polymers. By functionalizing olefins with nonlinear optical (NLO) chromophores and using late transition metal insertion catalysts of the form (bipy)Pd(CH 3)+ X- (X = OTf or BArF- ), a series of NLO materials were synthesized. These novel NLO polyketones were produced in modest yields with excellent polydispersities and good thermal stabilities via the alternating insertion of CO and NLO-tethered olefin into the palladium-carbon bond of the catalyst. A variety of NLO insertion monomers were examined during this study, beginning with a series of allylic-based monomers and progressing to a number of styrene derivatives. A detailed investigation of the copolymerizations and attempted copolymerizations is presented.