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Showing 1 to 20 of 63 for “"Friedel-Crafts"”.
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An Investigation of the Friedel-Crafts Condensation With Homoterpenyl Methyl Ketone.
In recent years many naturally occurring substances have acquired a great deal of attention, due primarily to their biological or synthetic values. -Pinene is the well known naturally occurring substance which is the main component in longleaf or slash pine tree oleoresin. a-Pinene and some of its …
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Friedel-crafts acylation reactions using heterogeneous catalysts stimulated by microwave radiation
Ion exchanged zeolites, ion exchanged clays, sulphated zirconia and silica supported phosphotungstic acid were prepared. Characterisation of the catalysts using pyridine adsorption revealed the catalysts contained both Brønsted and Lewis acid sites. When the catalytic activities for the acylation …
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The application of silica-alumina catalysts to a Friedel-Crafts type reaction
The development of the Friedel-Crafts reaction using anhydrous aluminum chloride in the condensation or aromatic hydrocarbons and alkyl or acyl halides has resulted in many new and diversified applications of this reaction, such as the preparation of hydrocarbons, keto acids, acids, ketones, and …
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A Mechanistic and Synthetic Study of Beta, Gamma-Unsaturated Ketone Formation by Friedel-Crafts Acylation of Mono-Olefins
Made available in DSpace on 2014-12-13T20:10:47Z (GMT). No. of bitstreams: 1 8008976.pdf: 6530518 bytes, checksum: dd7e2c05a022949443a269666a5ca567 (MD5) Previous issue date: 1979
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Acylation de composés aromatiques catalysée par des catalyseurs hétérogènes
La réaction de Friedel-Crafts est une réaction très importante non seulement en chimie organique, mais également dans l’industrie. Elle consiste en la formation d’une liaison sigma carbone - carbone et permet de ce fait de substituer une chaîne hydrocarbonée à un proton d’un noyau benzénique. Le …
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Enantioselective Conjugate Additions to a Hindered Cyclohexenone System
… carbon<sup>3</sup> nucleophiles, intramolecular Friedel-Crafts alkylations were explored. These conjugate additions have enantioselectively formed 6-6-6 and 6-5-6 tricarbocyclic ring systems. The framework of multiple tetracyclic diterpenes has also been achieved through chiral auxiliary removal …
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Progress Toward the Synthesis of 3-Methoxyflavones as Potential Antioxidants, Neuroprotective Agents, and Trifluoromethylated 19F NMR Probes
… was feasible. Other reactions like the Friedel-Crafts acylation and selective protection of phenols were also difficult.
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Synthetic approaches to a hypervalent trigonal bipyramidal carbon species and a versatile reagent for the oxidation of primary and secondary alcohols to aldehydes and ketones
… Part I. The key step involves an intramolecular Friedel-Crafts reaction of a triarylmethyl cation. Some reactions of this methanol derivative are presented as part of an attempted synthesis of a hypervalent (10-C-5) trigonal bipyramidal carbon species.
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Synthesis of Functionalised Cobalt Sandwich Complexes for Application in Asymmetric Catalysis
… sandwich complexes was realised using the Friedel-Crafts reaction. Complex (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt underwent reaction with acid chlorides/aluminum chloride to give exclusively para-acylation. Reaction of unsymmetrical bis-aryl alkynes …
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Stress relief: Exercising Lewis acid catalysis for donor-acceptor cyclopropane ring-opening annulations, a basis for new reaction methodologies
… construction of functionalized polycycles using Friedel-Crafts-type alkylation sequences are presented to expand the reaction repertoire of the molecular architect. Generally, products were formed from commercially-available starting materials in high yields with broad scope. The methodologies …
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Metal catalyzed generation of reactive benzomethane intermediates for the synthesis of benzopyrans, tetrahydroquinolines and chiral aryl methanes
… alcohols and methyl eugenol demonstrate Friedel-Crafts reactivity with the benzomethane intermediates. In this work, a one-pot, multicomponent reaction with phenols, aldehydes, and olefins provide efficient access to benzopyrans. Iron (III) salts mediate the initial benzomethane formation …
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Reacciones de Ciclación Catiónica y su Aplicación en Policiclaciones Biomiméticas y en Síntesis de Productos Naturales
… que sufre una ciclación intramolecular tipo Friedel–Crafts reductiva, en la cual el disolvente (HFIP) participa activamente. Este estudio abre una nueva vía para acceder a esqueletos carbocíclicos con potencial aplicación como bioisósteros del naftaleno.
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Carbon-Carbon Bonds Formed by Lewis Acid Catalysis or Photoactivation
… 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, photoactivation of tosylhydrazones can allow for C–C bond formation when …
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Mesoporous Carbon/Silica Encapsulated Molybdenum and Ruthenium Nanocatalysts For Green Chemistry Applications
… to be efficient and robust catalysts for Friedel-Crafts alkylation, oxidative desulfurization, and carbon dioxide hydrogenation reactions.
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Aromatic acetals : their synthesis and alkylation
… These conditions are the same imposed by a Friedel Crafts reaction or a Fries rearrangement.</p>
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C‒H-Silylierung und C‒H-Formylierung von Aromaten unter Verwendung kationischer Siliciumelektrophile
… erzeugt. Damit gelang es, eine intramolekulare FRIEDEL–CRAFTS-artige Silylierung von ortho-silylierten Biphenylen zu entwickeln. Die Produkte dieser Reaktionen sind dibenzanellierte Silole, die als Bausteine π-konjugierter Polymere Einsatz finden. Daher sind katalytische Synthesen zum Aufbau …
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Syntheses of C-glycoside natural products via oxocarbenium cationic intermediates
… cation via an intramolecular Marson-type Friedel-Crafts cyclization, which concomitantly generates the chiral quaternary center. The third chapter illustrates the formal syntheses of (+)-brussonol and (+)-abrotanone, attained in a convergent and concise manner, making these syntheses the …
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