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Showing 1 to 13 of 13 for “"Lewis Acid Catalysis"”.
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Lewis acid catalysis in organic synthesis
"Gadolinium triflate (Gd(OTf)₃) was found to be a simple and efficient catalyst for the acetylation of alcohols and amines in both conventional organic solvents and as well as in room temperature ionic liquids (TRIL). Acetylation reactions using acetic anhydride as the reagent proceed in excellent …
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Carbon-Carbon Bonds Formed by Lewis Acid Catalysis or Photoactivation
… from propargylic alcohols, organoboronates, and Lewis acids. Lewis acids can also be used to facilitate a mild Friedel-Crafts reaction between electron-rich aromatics and allylic or benzylic alcohols. Moreover, these methods can be applied to the synthesis of natural products. Finally, …
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Probing the Impact of Solvent on Lewis Acid Catalysis via Fluorescent Lewis Adducts
… have been developed to measure the strength of a Lewis acid. However, a major challenge for these measurements lies in the complexity that arises from variables, such as solvent and other fundamental interactions, as well as perturbations of Lewis acids as their reaction environment changes. …
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Stress relief: Exercising Lewis acid catalysis for donor-acceptor cyclopropane ring-opening annulations, a basis for new reaction methodologies
… other relevant scaffolds. Unique, efficient, Lewis acid-catalyzed intramolecular cyclization strategies for the construction of functionalized polycycles using Friedel-Crafts-type alkylation sequences are presented to expand the reaction repertoire of the molecular architect. Generally, …
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Inter- and intramolecular (4+2) cycloaddition reactions and tandem inter- and intramolecular (4+2)/intramolecular (3+2)cycloaddition reactions of nitroalkenes
… cycloadditions of nitroalkenes with Lewis acid catalysis were investigated. The intramolecular cycloadditions of nitroalkenes were found to be completely stereoselective for trisubstituted nitroalkenes. Intermolecular cycloadditions of aromatic nitroalkenes were found to proceed with …
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Applications of 2,3-Diketoesters in Organic Synthesis and Stereoselective Transformations
… yield to form dihydrofuranols that undergo acid catalyzed dehydration under mild conditions to generate 3-methoxyfuran-2-carboxylates in good yield. Oxidation of ζ-keto-α-diazo-β-ketoesters that are formed by zinc triflate catalyzed Mukaiyama-Michael condensation of methyl diazoacetoacetate …
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Heterogenous catalysis of inorganic reactions
… aluminium species are necessary for successful catalysis of the reactions and the greater the number of these sites the faster the aquation. The aluminosilicates act simultaneously as bi-functional catalysts, i.e. as proton acceptors (base catalysis) and as electron pair acceptors (Lewis acid …
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The Development of Cyclobutenone, and Other Work
… again diverged in reactivity and selectivity. Lewis acid catalysis reduced this gap to give high levels of endo addition across the series. This stereochemical information was then translated to trans hydrindene junctions by controlled fragmentation of erstwhile dienophile moieties. …
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A Lewis Acidic Stroll Through the p-Block
Since the inception of frustrated Lewis pair (FLP) chemistry more than a decade ago, the development of an assortment of main group Lewis acids in the literature has contributed to the enrichment and diversification of FLP reactivity to achieve transition metal-like chemistry. While most of the …
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Applying Trichloroacetimidates to the Synthesis of Benzylic Trichloroacetamides & Functionalized Indoles
… two different sets of conditions: thermal and Lewis-acid catalyzed (TMSOTf). The corresponding secondary benzylic trichloroacetamides were produced in good to high yields with either protocol. The convenience of having two protocols was demonstrated in the study as it allows for extensibility …
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Thermochemical Interconnectivities of Active Sites on Metal Oxides and their Catalytic Consequences in C−O Formation and C−H Scission Chemistry
… protons on lattice O-atoms act as Brønsted acid sites (H+), the coordinatively unsaturated cationic metal centers function as Lewis acid sites (Mδ+−Oδ−), and the anionic lattice O-atoms serve as redox sites (O*). These active sites coexist and collectively catalyze both parallel and …
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Method Development Towards Catalytic Transformations of Reactive Intermediates
… We were able to accomplish such under broad Lewis acid catalyzed methods. Secondary goals, once a method was established, were to understand the mechanistic and physical parameters of the reaction process such that the limitations and scope could be detailed for future development and …
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Mechanism and application of Lewis and Brønsted acid effects in organotransition metal catalysis
… described here address concepts in homogeneous catalysis and organometallic chemistry, with a focus on method development for catalytic reaction applications in organic synthesis. The unifying theme throughout the research is the development of rational design principles for cooperative …