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Showing 1 to 20 of 30 for “"ring-opening reactions"”.
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Enantioselective ring opening reactions catalysed by heterogenized metal salen complexes
… in high enantiomeric purity via asymmetric ring opening reactions. These products are valuable chiral intermediates for the preparation of several pharmaceutical agents. Although the catalytic performance of this type of catalyst is excellent, their use on an industrial scale is limited due …
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Abnormal Ring Expansion and Ring Opening Reactions of Polycyclic Aziridinium Salts
Made available in DSpace on 2014-12-09T17:36:46Z (GMT). No. of bitstreams: 1 7020952.pdf: 2995112 bytes, checksum: 8e7ee1ff79eda4f26fde61893c1977a3 (MD5) Previous issue date: 1970
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Cascade Annulation and Ring-Opening Reactions of Castagnoli-Cushman-Derived Allylic and Benzylic Thiomorpholinonates
… metal-free, base-mediated cascade reaction featuring methylesterification of allylic thiomorpholinonyl acids and concomitant regioselective intramolecular hydroalkylation is described. The method hinges on the <em>in-situ</em> generation of a transient [4.1.0] bicycle, which undergoes selective …
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Ring opening reactions of some dialkyl substituted 1, 3, 2-dioxathiolan-4-one-2-oxides
… acids has been studied. In thermal decomposition reactions the length of the nalkyl group in methyl, n-alkyl substituted compounds of this type was found to primarily affect the rate rather than the mechanism of the reaction. The first-order rate determining ring scission process, leading to the …
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ADVANCES IN THE DIRECTED ORTHO METALATION, SUZUKI-MIYAURA CROSS COUPLING, AND RING-OPENING REACTIONS OF INDAZOLES. SYNTHESIS OF LUMINESCENT ACRIDINE AND NOVEL INDAZOLE-BASED OXAZABORINES
… alongside many other well-established reactions, has led DoM into the modern age of synthetic organic chemistry. Chapter one of this thesis begins with a brief review of traditional approaches for the carbon and nitrogen functionalization of indazoles and the reactivity challenges faced …
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Asymmetrische Synthese von Sulfonsäurederivaten
… protected taurine-derivatives. Additionally, the ring-opening reactions of sultones with heteronucleophiles and the Michael-reactions of sulfonic acid esters with various Michael-acceptors were investigated.
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Ultrafast reaction dynamics of polyatomic molecules probed by ionization
… dynamics of the photoinitiated electrocyclic ring-opening reactions of 1,3,5-cyclooctatriene and 7-dehydrocholesterol are investigated in a fs pump-probe experiment using ionization as the probe step. Concerning the 1,3,5-cyclooctatriene photoreaction, there are strong arguments for the …
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Borinic Acid-catalyzed Ring-opening of Epoxy Alcohols
… catalysis has been used by our group to effect ring-opening and rearrangement reactions of 2,3-epoxy alcohols via reversible borinate ester formation. This work focuses on expanding the mode of borinic acid catalysis to the activation of 3,4-epoxy alcohols for regioselective ring-opening …
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Investigating Rings: From Iridium-Catalyzed [4+2] Cycloadditions of Alkynyl Halides to Ring Openings of Cyclopropanated Oxabenzonorbornadiene
… part of this thesis describes acid-catalyzed ring opening reactions of cyclopropanated oxabenzonorbornadiene. First, the reaction was optimized for the acid source and temperature using methanol as a solvent and nucleophile, and then the scope of the reaction was expanded to a variety of other …
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A COMPUTATIONAL STUDY OF BONDING INTERACTIONS AND SURFACE CHEMISTRY ON METAL SUBSTRATES
… their unique physical properties and exploring diverse applications. To construct well-defined nanostructures through the bottom-up approach, a comprehensive exploration of on-surface bonding interactions and surface chemistry is crucial. In this thesis, Density Functional Theory (DFT) …
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The acidic sulfonimidation of aryl–oxazolines and the electrophilic fluorination of aryl–oxazolines
… directing groups for several different coupling reactions. In the exploration of using phenyl oxazoline as a directing group for electrophilic fluorination, it was discovered that acidic sulfonimide nucleophiles including dibenzenesulfonimide, o–benzenesulfonimide, dimethanesulfonimide, and …
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Applications for the activation of hydroxyl groups to nucleophilic attack
… areas: Cyclic five-membered thionocarbamates bearing a N-Boc group undergo ring opening reactions at the 5-C with soft nucleophiles such as thiophenolate, pyridine-2-thiolate and potassium thioacetate. Hard nucleophiles react at the thiocarbonyl group followed by a variety of successive reactions …
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Asymmetric synthesis of sultones and sulfonic acid derivatives
… via alpha-allylation of lithiated sulfonates bearing 1,2:5,6-di-O-isopropylidene-alpha-D-allofuranose as a chiral auxiliary has been developed. High asymmetric inductions of the alpha-allylations were achieved along with good to excellent yields. In all cases the diastereomerically pure allylated …
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Indole Arynes in organic synthesis : discovery and applications for the total synthesis of complex natural products
… in the many regioselective cycloadditions, ring-opening reactions, and rearrangements it exhibited.
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Development of New N-Cyclopropyl Based Electron Transfer Probes for Cytochrome P-450 and Monoamine Oxidase Catalyzed Reactions
… is presented in Chapter 2. The barrier for ring opening of aminyl radical cations derived from N-cyclopropyl derivatives of tertiary amines (such as MPTP) is expected to be low. Reactions of 3BP with all three compounds are very similar. The results suggest that the reaction between …
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Pericyclic reactions in organic synthesis
… reaction with an alkenyl or alkynyl dienophile. Reactions involving unsymmetrical alkenyl and alkynyl dienophiles proceed with good to excellent regioselectivity, and endo products are formed exclusively. The mechanism of several earlier fully intramolecular related transformations have been …
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Synthetic Studies Of Biologically Active Molecules: Irl 2500, Bruceantin, And Biliatresone
… as a possible method to generate the bruceantin ring system. The synthesis of suitable bicyclic substrates for this reaction has been achieved, and their viability in a rhodium- catalyzed cycloaddition has been evaluated, with nitrogen-containing bicyclic compounds having been shown to undergo …
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Geochemical Aspects of Waste Disposal
… and was extended to investigate ways of rendering phenol harmless using chemical means applicable to conditions encountered at a waste disposal site. In addition the possibility of finding a catalyst which may promote chemical reactions of phenol to afford less environmentally problematic …
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Ab initio computational applications to complex biomolecular systems
… configuration, and the electronic structure during this process were analyzed in details. At the extension of ~1.3-fold, the ring opening reactions occurred in the backbones. The backbone nicks appeared at elongations of ~1.40-fold. The whole process was accompanied by HB breaking and charge …
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Synthesis of 4-(trifluoromethyl)azetidin-2-one building blocks and their transformation into novel CF3-substituted amines and heterocyclic systems
… properties on the other hand, β-lactams bearing a trifluoromethyl group comprise interesting entities for the construction of novel targets with promising bioactivities. In this PhD thesis, the preparation and deployment of 4-trifluoromethyl-β-lactams as new building blocks toward a diverse …
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