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Showing 1 to 20 of 32 for “"Tetrasubstituted"”.
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Syntheses of tetrasubstituted azo- and azoxybenzenes
… object was to prepare series of symetrical tetrasubstituted axoxybenzenes as starting materials for a study of the Wallach rearrangement."
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Asymmetric hydrogenation of unfunctionalized trisubstituted and tetrasubstituted olefins
A highly reactive chiral catalyst for the asymmetric hydrogenation of aryl trisubstituted olefins was generated by combining the complex (EBTHI)MMe2 (EBTHI = ethylenebistetrahydroindenyl, M = Ti, Zr) with [PhMe2NH]+[(BC6F5)4]- under a hydrogen atmosphere. A number of unfunctionalized trisubstituted …
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Enantioselective synthesis of 2,2,5-Tri- and 2,2,5,5-tetrasubstituted tetrahydrofurans and synthesis of diketopiperazine containing natural products
… can be stereoselectively transformed into tetrasubstituted tetrahydrofurans via ring-opening metathesis/cross-metathesis or oxidative cleavage and refunctionalization. A partial synthesis of the bioactive diketopiperazine containing natural product gliocladin C was achieved in nine steps, …
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Part A The application of fluorescence resonance energy transfer to reaction discovery Part B The stereodefined synthesis of tetrasubstituted olefins
… Part B describes the stereodefined synthesis of tetrasubstituted olefins. 2-Alkynyl esters were selectively converted to E-beta-chloro-alpha-iodo-alpha,beta-unsaturated esters by exposure to Bu4NI in refluxing dichloroethane. These products were produced cleanly, regio- and stereoselectively, and …
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A systematic study of Wallach rearrangement
… of a large number of symmetrical di- and tetrasubstituted azoxybenzenes. A second aim was the synthesis of new polysubstituted hydroxyazobenzenes."
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Part I. Solvolysis of Caryophyllen-8-Yl Derivatives: Model Reactions for Presilphiperfolanol Biogenesis. Part II. Stereochemistry of Lithium-Amine Reductions of Tetrasubstituted Epoxides and Phenylthiohydrins to Tertiary Alcohols
… of the Li-amine reductions of model bicyclic tetrasubstituted epoxides and the corresponding trans-phenylthiohydrins was carried out to determine the stereochemistry and optimal reaction conditions for this transformation. Octalin, hydrindene, and bicyclo (3.3.0) octene epoxides were …
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Design, synthesis, and evaluation of bioactive molecules; Chiral polyvinylpyrrolidones supported Cu/Au nanoclusters catalyzed cyclization of 5-substituted nona-1,8-dien-5-ols
… cyclized lactone possessing a stereogenic tetrasubstituted carbon center was formed in a one-step Cu/Au nanoclusters-hydrogen peroxide oxidation reaction. This developed a novel and simple method to synthesize tetrasubstituted carbon stereogenic center. Drawbacks of the method in my initial …
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A. Discovery of novel reactivity under the Sonogashira reaction conditions B. Synthesis of functionalized BODIPYs and BODIPY-sugar conjugates
… coupling conditions was found to give 1,2,4,6-tetrasubstituted benzenes instead of Sonogashira coupled product. The reaction conditions and substrate scopes for these two new reactions were investigated. B. BODIPY core was functionalized with various functional groups such as nitromethyl, …
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Applications of 2,3-Diketoesters in Organic Synthesis and Stereoselective Transformations
… gives high selectivity for the 1,3-anti tetrasubstituted cyclopentanones, whereas Brønsted acid catalysis produces the corresponding 1,3-syn diastereomer. The first enantioselective transformation of 2,3-diketoesters was demonstrated in carbonyl-ene reactions catalyzed by …
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Asymmetric nickel-catalyzed three-component assembly of allylic amines from alkynes, imines and organoboron reagents
… developed to provide enantiomerically enriched, tetrasubstituted allylic amines in a single operation. Using the complex derived from Ni(cod)2 and a P-chiral ferrocenyl phosphine A, both aliphatic and aromatic alkynes and imines undergo coupling reactions in high yields (up to 95%) and …
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Intramolecular Anodic Olefin Coupling Reactions: Synthesis Of Nitrogen- And Oxygen-Heterocycles
… and pipecolic acid derivatives with alpha-tetrasubstituted carbon atoms despite the oxidation potential of the product being significantly lower than either functional group in the substrate. The competing oxidation of the product was avoided because the oxidation potential of the substrate …
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Design, Synthesis And Biological Evaluation Of Small Molecules That Inhibit Hiv-1 Entry And Sensitize Hiv-1 Infected Cells To Immune Responses
… strategy for the synthesis of 1,2,5,7-tetrasubstituted aminoindane small molecule CD4mc and the corresponding biological evaluation. The second part highlights the discovery and development of a new structural class of small molecule CD4mc with the capacity to elicit ADCC responses that …
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Copper-catalyzed conjugate reduction
… catalyst for the 1,4-reduction of tri- and tetrasubstituted a,f3-unsaturated esters and cyclic enones. The active catalytic species can also be generated in situ from 1,3-bis(2,6-di-isopropylphenyl)-imidazolium chloride and CuCl2.2H20 in the presence of NaOt-Bu and PMHS.
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Ruthenium Hydride Catalyzed Silylvinylation of Alkynes
… anti-exo-dig cyclization which affords a tetrasubstituted olefin with a new vinylsilane, and a highly functionalized Z,E diene motif. Subsequent studies for a highly selective intramolecular trans-silylvinylation of internal alkynes catalyzed by RuHCl(CO)(SIMes)(PPh3) is reported. The use …
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Gold(I) and Platinum(II)-Catalyzed Hydrofunctionalization of Allenes and Alkenes with Carbon and Nitrogen Nucleophiles
… for monosubstituted, 1,3-disubstituted, and tetrasubstituted allenes and various indoles.</p> </p><p><p>Platinum(II) bis(phosphine) complexes catalyzed the intermolecular hydroamination of monosubstituted allenes with secondary alkylamines in good yield with selective formation of …
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Pushing the Limits of the Lithium Indicator Carbon Acidity Scale Using Cyclopentadiene Chemistry and 19F NMR Spectrometry
… ca. pK = −6. To achieve this result, a set of 11 tetrasubstituted cyclopentadienes were synthesized and their acidities evaluated sequentially with the goal of reaching a low pK value while minimizing the acidity ratio at each incremental step. The four ring substituents were combinations of …
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Synthetic Study Of Karlotoxins And Investigation Of Alpha-Diaminoboryl Carbanion Chemistry
… variety of substituted acrylonitriles, including tetrasubstituted alkenes, by olefinating aldehydes and ketones. We have also demonstrated a useful application of the α-boryl carbanion species for the synthesis of 2-aminoquinoline-based alkaloids.
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