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Showing 1 to 13 of 13 for “"Nickel catalysis"”.
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Enantioselective nickel catalysis : exploiting activated C-H bonds
A method for the nickel-catalyzed cross-coupling between benzoxazole and secondary halides was explored. This method was to make use of the activated C-H bond found in benzoxazole at the 2-position to generate the nucleophilic species in situ. After an extensive survey of parameters no such method …
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Exploring Nickel Catalysis in Carbonyl and Alcohol Addition Reactions
The nucleophilic addition of organomagnesium/lithium reagents to aldehydes and ketones has long enabled the synthesis of valuable alcohol derivatives; however, these types of transformations are often plagued by poor functional group tolerance and require harsh reaction conditions. The direct …
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Synthesis and use of bench-stable precatalysts with heck-type activation and progress towards the continuous-flow synthesis of atorvastatin
… new class of bench-stable N-heterocyclic carbene nickel precatalysts for homogeneous nickel-catalysis. The nickel(II) complexes are readily activated to Ni⁰ in situ under mild conditions, via a proposed Heck-type mechanism. The precatalysts are able to facilitate carbonyl-ene, hydroalkenylation, …
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Electrophilic Cyanation of Alkenyl Tosylates, Ketones and Amines using Disubstituted Malononitriles
… electrophilic cyanating reagents under reductive nickel catalysis. Chapter 3 describes a novel method for the synthesis of β-ketonitriles from ketones and disubstituted malononitriles under basic conditions. Several β-ketoenamines were found to be produced using similar conditions, and their …
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The nickel-catalyzed Mizoroki-Heck reaction : high regioselectivity in Olefin migratory insertion and photoredox-enabled indoline formation
… has been a longstanding challenge. Using a nickel-catalyzed cationic Heck reaction, we were able to achieve excellent selectivity for branched products (>/=19:1 in all cases) over a wide range of aryl electrophiles and aliphatic olefins. A bidentate ligand with a suitable bite angle and …
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Mechanistic Studies and Rational Catalyst Design of Nickel/Photoredox Dual-Catalyzed C–C Cross-Coupling Reactions
The merging of photoredox and nickel catalysis has revolutionized the field of C–C cross-coupling. However, in comparison to the development of synthetic methods, detailed mechanistic investigations of these catalytic systems are lagging. In this vein, computational tools have been applied to …
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Exploration of the use of Palladium and Nickel to Catalyze Enolate Cross-coupling and the Enantioselective Mizoroki-Heck Reaction.
<p>Palladium catalysis is a common synthetic tool utilized by organic chemists to create carbon-carbon bonds. We utilized palladium to catalyze the γ-arylation of α, β-unsaturated ketones, and esters. This work expands on palladium-catalyzed α-arylation chemistry and extends it to the vinylogous …
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Total synthesis enabled by nickel-catalyzed transformations: Dearomative carboamination and methylenecyclopropane annulation
The use of base metal catalysis is becoming increasingly important, as the sources of transition metals commonly used for the preparation of complex molecules are diminishing. Furthermore, application of these base metal catalysts to the total synthesis of natural products would allow for novel …
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Synthese und Charakterisierung von Copolyarylenen : neue Polyelektrolyte für Brennstoffzellen
Ziel der Arbeit war die Synthese von neuen Polymerelektrolyten für Brennstoffzellen. Für diese Anwendung wurden neue Polyarylene ohne aliphatische Seitengruppen realisiert. Sämtliche synthetisierten Polymere waren löslich in N,N-Dimethylformamid (DMF) oder Chloroform, was eine homogene …
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Developments in Nickel-catalyzed Transfer Hydrocyanation Reactions and Novel Skeletal Editing Strategies through Nitrogen Atom Insertion
… of highly hazardous HCN. Herein, a focus on nickel- and Lewis acid-co-catalyzed transfer hydrocyanation using isovaleronitrile or butyronitrile as sacrificial HCN donor reagents is discussed (see Scheme I). Further developments allowed to circumvent the use of air- and temperature-sensitive …
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Group 10 Metal Catalytic Olefin Polymerization and Synthesis of Ethylene/Acrylate Block Copolymers
The functionalized polyolefin materials are considered economical and high performance materials used in a wide range of applications, such as upcycling polymers, elastomers, membranes, and compatibilizers. This dissertation focuses on developing group 10 metal catalysts for olefin polymerization …
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Improved Synthesis, Separation, Transition Metal Coordination and Reaction Chemistry of a New Binucleating Tetraphosphine Ligand
… 1 focuses on motivation for using bimetallic nickel phosphine complexes as possible catalytic precursors for alkene hydration. Chapter 2 describes studies into alkene hydration in the presence of catalytic amounts of dinickel phosphine complexes based on linear tetraphosphine ligand, …
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Studies of Carbon Dioxide Methanation and Related Phenomena in Porous Catalysts
… the kinetics of CO2 methanation over nickel and cobalt catalysts. Methanation was studied for both Ni/γ-Al2O3 and Co/ZrO2 catalysts, which were synthesised using an incipient wetness impregnation technique and subsequently characterised using analyses based on gas adsorption, XRD, TPR …