Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 39 for “"Carbon-Carbon Bonds"”.
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Carbon-Carbon Bonds Formed by Lewis Acid Catalysis or Photoactivation
Methods to generate C¬–C bonds are of great interest to synthetic organic chemists. Ideally, these reactions will be simple, robust, and catalytic. Herein is described the synthesis of tertiary and all-carbon quaternary centers from propargylic alcohols, organoboronates, and Lewis acids. Lewis …
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Breaking carbon-carbon bonds with cytochrome P450s from plants, animals, and bacteria
This Dissertation was approved for publication on 2022-04-19 at 13:48.
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New methods for the formation of carbon-carbon bonds via organometallic compounds
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1995.
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Trichloroacetimidates As Outstanding Electrophiles for the Carbon-nitrogen, Carbon-oxygen and Carbon-carbon Bonds Formation and Synthetic Studies of Protein Phosphatase-5 (pp5) Small Molecule Inhibitors
<p>Trichloroacetimidates have been previously used for glycosidic bond formation in carbohydrate chemistry and in Friedel-Craft reactions. Traditionally, trichloroacetimidates had be synthesized using an alcohol and strongly basic conditions, but in recent years milder preparation methods have been …
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Brønsted acid-catalyzed reaction of alkynyltrifluoroborates with acetals and ketals
… compounds. Specifically, the formation of new carbon-carbon bonds is of great importance in synthetic organic chemistry. Brønsted acid catalysis is a powerful synthetic tool to make many different compounds, however, the current carbon-based nucleophiles are the major limitation of …
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Transition Metal-Catalyzed Preparation and Functionalization of Nitrogen-Containing Heterocycles
The formation of carbon-carbon bonds is the single most fundamentally important operation in synthetic organic chemistry. Arguably, the aldol and Diels-Alder reactions stand as the most significant advances in forging linkages between carbons of an sp3-hybridized nature. Beginning in the early …
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Part I. Approaches Toward the Total Synthesis of Tyloindicine F; Part II. Palladium-Catalyzed C−H Functionalization of β-enaminones
… is a highly efficient method of constructing new carbon-carbon bonds. β-enaminones are highly polarized and their β; position is suitable for C-H functionalization by means of electropalladation. A novel methodology for the oxidative Hiyama coupling of β-enaminones has been developed and two new …
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Asymmetrische Organokatalyse zu Alpha-Fluorierung von Aldehyden und Ketonen und zur Synthese von Cyclohexencarbaldehyden via Dominoreaktionen
… Due to their two activation modes of several carbonyl compounds, namely enamine catalysis (HOMO-raising) and iminiumion catalysis (LUMO-lowering), they are capable to catalyze a broad variety of different reactions, which explains increasing application of these catalysts in organic synthesis. …
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STEREOSPECIFIC SUZUKI-MIYAURA CROSS-COUPLING OF CHIRAL BENZYLIC BORONIC ESTERS AND VINYL BROMIDES
… is a powerful method for the construction of carbon-carbon bonds in academia and industry. Despite extensive research in this area and the significance of the reaction, it is most often employed to prepare flat, Csp2-Csp2 bonds between two aryl groups. Since most bioactive compounds contain …
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The Stetter reaction : synthesis of complex spiro Bis-indanes and studies on quaternary centre formation
… moderate to high diastereomeric ratios. Three carbon-carbon bonds, including the hindered quaternary center at the spiro ring junction, form at a remarkable rate under mild reaction conditions. Spiro bis-indanes 39 are also produced in moderate to good yields through the Stetter-aldol-aldol …
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Biomimetic synthesis of meroterpenoid natural products using dearomatization strategies
… cyclization cascade reaction, where four new carbon-carbon bonds, four new carbocyclic rings and five new stereocentres were formed in the one step. The first total synthesis of merochlorin A was achieved in five linear steps from methyl-3,5- dimethoxyphenylacetate (6% overall yield). The key …
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New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
… have been widely used for the formation of carbon-carbon bonds. This type of reaction has the potential to circumvent protection and deprotection steps, shortening an overall synthetic process.</p><p>The Morita-Baylis-Hillman (MBH) reaction is a particularly notable example of an anionic …
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How do metalloenzymes propagate and control chemical reactions?
… radical reactions and reactions cleaving carbon-carbon bonds. Metalloenzymes, which contain a metal cofactor, are particularly adept at propagating these reactions. This thesis focuses on several metalloenzymes; each an example of a different unique reaction control strategy. Both …
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Characterization of Cyclopropyl Synthases Involved in the Maturation of Ribosomally Synthesized and Posttranslationally Modified Peptides
… have been shown to install ether, thioether, and carbon-carbon bonds on the precursor peptide. These modifications usually define the backbone structure of the mature RiPP. This thesis describes the characterization of a novel RiPP modification catalyzed by the radical S-adenosylmethionine enzyme …
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Ligand design principles for perfecting stereoretention in Suzuki-Miyaura cross-coupling of unactivated CSP3 boronic acids
… block assembly is finding reactions to forge carbon-carbon bonds between a range of structurally diverse building blocks. Iteration of metal-mediated cross-coupling reactions represents a promising direction, and such an approach has already been automated and used to make many different small …
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Total synthesis of cyclotryptamine and diketopiperazine alkaloids and biosynthetic pathway investigation of unsymmetrical diketopiperazine dimers
… formation of all C3a-C3a' and C3a-C7' carbon-carbon bonds and all the associated quaternary stereogenic centers. The synthesis of these complex diazenes was made possible through a new methodology for synthesis of aryl-alkyl diazenes using electronically attenuated …
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Stereoselective synthesis : studies involving dipole-stabilized carbanions alpha to nitrogen
… endeavour. The ability of organolithiums to form carbon-carbon bonds in a stereoselective and predictable way is vital to their success in organic synthesis. The first chapter in this thesis summarizes the current mechanistic understanding of asymmetric carbon-carbon bond formation adjacent to …
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Broadening the scope of reactivity for neutral organic electron donors
… of the reductive bond cleavage of various σ-bonds. Photoactivation of donor A (to A*) has been discovered to increase the reducing power of the species therefore allowing the reduction of less activated bonds and this body of work explores examples such as: carbon-nitrogen bonds of benzyl …
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Mathematical Analysis of Compressive/Tensile Molecular and Nuclear Structures
… geometry of single, double, or triple carbon-carbon bonds gives an unsatisfying demonstration of bond lengths, compared to experimental trends. To correct this, Platonic solids and Archimedean solids were evaluated as atoms in covalent carbon or nitrogen bond systems in order to find …
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Synthesis and hydrogenation of iridium complexes with bidentate and water-soluble phosphine ligands: developing novel water-soluble catalysts for hydrogenation of unsaturates
The hydrogenation of unsaturated carbon-carbon bonds catalyzed by transition metal hydrido complexes has received considerable attention in the literature. Environmental interests have placed considerable emphasis on switching these processes into aqueous media. The dimeric complex [Ir(COD)Cl]₂ …
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