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Showing 1 to 20 of 20 for “"Cope Rearrangement"”.
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Diastereoselective aza-cope rearrangement-mannich cyclizations of conformationally mobile iminium cations
… a Lewis-acid catalyzed, diastereoselective aza-Cope rearrangement— Mannich cyclization (ACM) to form acyl pyrrolidines from conformationally mobile substrates. Earlier studies from our lab have shown that substituted acyl pyrrolidines can be synthesized with diastereoselectivity of 50:1 …
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Sequential Enantioselective Iridium-Catalyzed Allylic Alkylation/Cope Rearrangement for the Construction of Acyclic γ-Tertiary or Quaternary Stereocenters
… iridium-catalyzed allylic alkylation/Cope rearrangement to provide an efficient method approach to acyclic γ-tertiary and quaternary stereocenters. The following thesis is divided into four chapters, which encompass a comprehensive literature review followed by two research chapters, …
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Development of a microwave-assisted epoxide aminolysis and investigation of the aza-cope rearrangement--mannich cyclization for alkaloid synthesis
… other methods were used to investigate the aza-Cope rearrangement—Mannich cyclization. We proposed that this procedure could be used to produce compounds we could modify and transform into several alkaloids.</p>
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Anionic Amino-Cope Rearrangement Studies and Development of Designer Sulfur-Rich Materials using Sulfur, Sulfur Monochloride and Dithiophosphoric Acids
… related to the explorations of new anionic amino-Cope cascade reaction as well as development and characterizations of new sulfur-rich materials. Chapter 1 presents diverse results of the anionic amino-Cope cascades when strategically employing γ-substituted dienolates nucleophile. In Chapter 2, …
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Three-Way Chemoselectivity Switching through Coupled Equilibria in Complex System and Post-synthetic Modification of Cyclobenzoins
… This dissertation focuses on the use of diaza-Cope rearrange as a dynamic reaction in a complex system, as well as the synthesis of the derivatives of cyclotetrabenzoin. Chapter One, selected research literature about the application of coupled equilibrium which gives the emergence properties …
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Anion Relay Cyclopropanation and Aryl Vinyl Cyclopropane Cope Rearrangements
… focused on silicon and phosphorus Brook rearrangements to effect anion relay. Presented herein is the development of a retro-Claisen condensation protocol to effect anion relay in the synthesis of vinyl cyclopropanes, and subsequent aromatic Cope rearrangement of those vinyl …
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Evaluation of camphor derivatives in terpenoid synthesis
… (36) and subsequent anionic oxy-Cope rearrangement of the resulting 1,5-diene (64) provided hydrindenone 66. Ring expansion of 66 provided decalin intermediate 69 which contains the A/B ring system common to many terpenoids; however, the stereo-specific introduction of an angular …
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THREE STUDIES OF 2-PYRIDONE PHOTOADDUCT REACTIVITY
… Halogenation of trans iv give rearranged i. Cope rearrangement of cis v gives vi which can undergo retro-Mannich reaction to yield unsymmtrically coupled piperidines vii. Pyridones can also undergo photo-[4+4] reactions with furans. Cycloaddition of viii yields ix. Transannular closure of ix …
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Strategic Applications of Tandem Reactions in Complex Natural Product Synthesis: Rapid Access to the (Iso)Cyclocitrinol Core
… in order to validate our ring contraction-Cope rearrangement strategy. Novel chemistry was then identified to access the functionalized core in enantio-enriched form. Finally, in line with our efforts to probe the transition state of our key tandem Claisen-Cope reaction, additional …
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Part 1. Diaziridinium Ions: First Reported Synthesis and Reactivity Studies. Part 2. Tropylium Ion Mediated alpha-Cyanation of Amines. Part 3. Multicatalytic Synthesis of Complex Tetrahydrofurans
… During this study, we have uncovered a practical rearrangement to access 2,3-benzodiazepines reliably and efficiently. Efforts to achieve N-transfer from these species are described and are ongoing. We have identified the tropylium ion as a highly efficient organic-based amine oxidant and have …
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Advancements in the diastereoselective synthesis of acyl pyrrolidines via the tandem aza-Cope—Mannich cyclization pathway
… a Lewis-acid catalyzed, diastereoselective aza-Cope rearrangement— Mannich cyclization to form acyl pyrrolidines from conformationally mobile substrates. In earlier studies from our lab, Brønsted acid-catalyzed reactions to form the same acyl pyrrolidines resulted in diastereoselectivities of …
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Novel reactions of ceph-3-ems
… C-2 exocyclic bond systems via a Pummerer rearrangement is described. Attempts at a Pummerer rearrangement of (D) and (E) failed.<br/><br/>Numerous attempts at a Cope rearrangement on ceph-2-em sulphoxide (G) and sulphide (H) failed.<br/><br/>De-esterification reactions of the new …
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Cycloaddition-fragmentation mediated pathways to ring D modified 19-norsteroids
… was developed which relied on an anionic oxy-Cope rearrangement as the key step. Thus methylenation of the cycloadducts derived from reaction of the dienyl acetate and selected dienophiles (acrolein and methyl vinyl ketone) gave after hydrolysis of the bridgehead ester, substrates which …
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Carbomagnesium mediated reactions: A versatile tool in organic synthesis.
… ring system underwent a facile enone accelerated Cope rearrangement to generate a bicylco[2.2.2]octanone ring system (330). Finally, the dienophiles prepared from the carbomagnesiation reaction were employed as key steps in the preparation of tether controlled intramolecular Diels-Alder reactions. …
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Application of electron spin resonance spectroscopy to problems of structure and conformational analysis: polysemiquinones and macrocyclic semidiones
… sec('-1) for the rate constant of the degenerate Cope rearrangement.</p>
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Novel imprinted polymers as artificial enzymes
… synthesis of an MIP which would catalyse the oxy-Cope rearrangement were carried out but the results were inconclusive.
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Synthesis and structure-activity relationships of ring D alkyl 19-norsteroids
… followed by base-mediated rearrangement of the hydroxy ketone to the thermodynamically preferred 16-ketone. Protection of the 17β-hydroxyl group as a TBS ether, followed by palladium acetate-mediated dehydrosilylation of the derived ∆¹⁵-16-trimethylsilyloxy enol ether gave …
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New reactivity and selectivity in transition metal-catalyzed C-C and C-N bond forming processes
… fragment enabled by the aromatization-driven Cope rearrangement. This method provides an effective means for the construction of adjacent tertiary and quaternary stereocenters with high levels of stereochemical purity. Chapter 7. Copper-Catalyzed Asymmetric Hydroamination of Unactivated …