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Showing 1 to 20 of 54 for “"enolate"”.
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The Magnesium Enolate of 2,2-Diphenylcyclohexanone
Made available in DSpace on 2014-12-05T19:36:53Z (GMT). No. of bitstreams: 1 5805399.pdf: 3154592 bytes, checksum: 739df3f15b717dfd15505f25dc31352f (MD5) Previous issue date: 1958
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The structure and reactivity of enolate anions.
Massachusetts Institute of Technology. Dept. of Chemistry. Thesis. 1965. Ph.D.
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Exploration of the use of Palladium and Nickel to Catalyze Enolate Cross-coupling and the Enantioselective Mizoroki-Heck Reaction.
… explored. This involved cross-coupling between enolates and aryl halides and between aryl halides and alkenes. Strategies for enantioselective synthesis were developed, and potentially bioactive phenanthridinone structures were constructed. Finally, the cross-coupling studies looked at both …
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Chemistry with chiral lithium amides: enantiotopic group and face-selective reactions
… This opened two new paths to develop tropinone enolate chemistry. One is indirect α-alkylation of tropinone, another is the nucleophilic attack from α-C enolate to the nitrogen atom. Seven interesting chiral amines have been synthesized and applied into the enolate chemistry of two interesting …
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Enantioselective Synthesis of Drug-like Molecules via Axially-Chiral Intermediates
… we hypothesized that a twisted amide enolate featuring a chiral C(O-)-N axis could sufficiently impart stereochemical information and control the selectivity of the reaction. Previous work completed by Kobayashi showed in related compounds (E)- vs (Z)-enolate formation could be …
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The SRN1 reactivity of halobenzenesulfonamides and related compounds
… of 2-halobenzenesulfonamides with ketone enolates. It was observed that with certain ketone enolates reduction to yield benzene sulfonamide competed with the substitution reaction. The presence of β-hydrogen atoms was a common structural feature of ketones used in reactions in which …
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Reactions of 4-chloro-2,6-dimethoxypyrimidine and 2-chlorothiazole with carbanion nucleophiles
… of 4-chloro-2,6-dimethoxypyrimidine (1) with enolates of acetone, pinacolone, diisopropyl ketone, and ethyl phenylacetate generated by means of potassium amide in 1 liquid ammonia were found to proceed by the S<sub>RN>1 mechanism upon photostimulation with near-UV light to give good yields of …
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The asymmetric synthesis of (2S,3R)-capreomycidine and the total synthesis of capreomycin IB
… The synthesis features a novel aluminum enolate-aldimine reaction with a chiral glycinate, which sets both stereocenters. A concise and high-yielding approach to the unnatural amino acid (2S,3S)-β-hydroxyornithine is also reported. The key step in this approach is a boron-mediated aldol …
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Cascade Transformations in Organic Synthesis: I. The Interception of Carbene Alkyne Metathesis Intermediates II. Photo-Activation of Hydrazones III. Organocatalyzed Cascade Conjugate Addition/Aldol Annulation of Organoboronates
… carbene alkyne metathesis intermediates, boron enolate intermediates, fused cyclopropene intermediates, and boronic acid intermediates. First, the multi-alkyne carbene cascade reaction under rhodium catalysis is discussed. Ten different diazoesters were synthesized and tested for cascade …
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Characterization of BphD, a C-C bond hydrolase involved in the degradation of polychlorinated biphenyls
… nm), consistent with an enzyme-bound, strained enolate (E:Sse). In studies with BphDLB400 variants, S112A trapped the E:Sse intermediate, implying that Ser112 is required for subsequent tautomerization and hydrolysis. His265 is required for E:Sse formation, as H265A variants instead generated a …
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Mechanistic Studies on Memory of Chirality Alkylations of 1,4-Benzodiazepin-2-ones & Structure-based Design of Insecticidal AChE Inhibitors for Malaria Mosquito, Anopheles gambiae
… We captured a transiently non-racemic BZD enolate intermediate in enantiopure form, then released the enolate and observed its subsequent reaction. This approach allowed the first ever step-wise observation of the stereochemical course of such a MOC process. Approximately 2 million deaths …
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Synthesis of novel heterocyclic α-amino acids
… the alkylation of a pseudoephedrine glycinamide enolate using haloalkanes. The method was validated by making the naturally occurring amino acid phenylalanine. Subsequently naphthyl-, pyridyl-, biphenyl- and isoxazolyl- groups were successfully incorporated into the amino acid side chain. The …
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Strategies towards the synthesis of prostaglandin analogues
… methodology to affect regiospecific enolate generation. Effective trapping of the enolate generates the requisite target. Within the context of this strategy both 2- and 3-component coupling protocols have been elaborated. Having demonstrated that the a- and p- sidechains could be …
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Application of Density Functional Theory to Study the Mechanism of Alkali Metal Enolate Oxidation by N-sulfonyloxaziridines, Umpolung Amide Synthesis from Halo-Amino-Nitro Alkanes, Alkali-Metal Catalyzed Transfer Hydrogenation of Ketones, and Asymmetric Catalyzed Aza-Henry Reactions
… reactions were studied: (1) Li+, Na+, and K+ enolate addition to chiral N-sulfonyloxaziridines, stereoselectivity was found to be controlled by enolate, sulfonyl, and oxaziridine oxygen-cation chelation and steric contacts. From this study it was found that the mechanism proceeded in a SN¬1 …
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An investigation of phase transfer catalysis employing quantitative structure-activity relationships
… on hydroxide-initiated PTC reactions, such as enolate alkylations. The tandem [4+2]/[3+2] cycloaddition of nitroalkenes was applied as the key transformation in the preparation of enantioenriched, tricyclic 1-hydroxy-cyclopentapyrrolizidine ring systems. A three-step parallel synthesis …
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The Evolution of Enzymatic Activity in the Crotonase Superfamily: The Mechanism of the Reaction Catalyzed by 2-Ketocyclohexanecarboxyl-Coa Hydrolase
… homologs, this reaction must proceed via a Z-enolate. Based on the information derived from stereochemical studies and site-specific mutagenesis, a mechanism of the reaction catalyzed by BadI was proposed, in which Ser 138 plays a central catalytic role. The new data is also related to the …
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Development and mechanistic investigation of the palladium-catalyzed α-arylation of aldehydes and N-arylation of ammonia
… with aryl bromides and chlorides. Arylpalladium enolate complexes of aldehydes were proposed as intermediates in this process, and these complexes were isolated and characterized. The effects of steric and electronic properties of the aryl groups on the rates of reductive elimination and yields …
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Design and Synthesis of Novel Benzodiazepines
… formation of an enantiopure, dynamically chiral enolate intermediate and the slow racemization of the enolate on the alkylation reaction time scale.
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Conjugate Additions and Transposition of the Allylic Alcohols of Enol Ethers of 1, 2-Cyclohexanedione.
… involved the enol ether preparation via the enolate, alkylation with an organometalic reagent, and oxidative rearrangement with pyridinium chlorochromate followed by the conjugate addition reactions. Protection of 1, 2-cyclohexanedione was achieved by reacting with chloro tert-butyldimethyl …
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Synthesis and Characterization of Hetero- and Homobimetallic Complexes of New Hard-Soft Binucleating Ligands
… methyl benzoate compounds with the potassium enolate of methyl ketones. The new binucleating ligands prepared in this work include phosphine, thioether and quinoline substituted (beta)-diketones along with the Schiff-base derivatives of the thioether (beta)-diketone. With these ligand systems, …
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