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Showing 1 to 20 of 53 for “"asymmetric catalysis"”.
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Asymmetric Catalysis in Polymersome Nanoreactors
Contains fulltext : 140662.pdf (Publisher’s version ) (Open Access)
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Fundamental and Applied Studies in Asymmetric Catalysis
… were synthesized as templates for asymmetric catalytic reactions that could involve substrate precoordination to a Lewis acidic site remote from the transition metal reaction site. Primary amines were found to bind reversibly via a nitrogen-boron interaction to the free ligands L*. …
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Asymmetric Catalysis with Brønsted Acids: Experiments and Calculations
… described herein focuses on enantioselective catalysis using BINOL-based Brønsted acids. The initial part of this work comprises the development of chiral phosphoric acids and N-triflylphosphoramides having alternative groups at the 3,3’- positions, different from the widely common aryl …
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Applications of planar-chiral heterocycles in asymmetric catalysis
The development of planar-chiral heterocycles for asymmetric catalysis and their applications to enantioselective processes were investigated. Reactions including the kinetic resolution of propargylic alcohols, the enantioselective ring opening of meso epoxides, and the asymmetric hydrosilylation …
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Novel Metal Amido-Complexes – Syntheses, Reactivity and Asymmetric Catalysis
… high selectivities and good activities in the asymmetric hydrogenation of ketones, the development of amido-complex catalysts for the enantioselective hydrogenation of imines represents a major focus of this work. A library of novel amines 4 was synthesized by deprotonation of the hydroxyl …
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Synthesis and application of pinene-pyridine derivatives in asymmetric catalysis
… derivatives, and their application in asymmetric catalysis. Both transition metal catalysed and organocatalytic transformations were investigated. Chiral pyridine-phosphines based on α-pinene were synthesised and applied as efficient P,N-ligands for the enantioselective …
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Synthesis of Functionalised Cobalt Sandwich Complexes for Application in Asymmetric Catalysis
The reaction of cobalt sandwich complex (η5-(N,N-dimethylaminomethyl)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt with sodium tetrachloropalladate and N-acetyl-D-phenylalanine gave planar chiral palladacycle …
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Design, synthesis and mechanistic studies of boron and phosphorus heterocycles and their applications in asymmetric catalysis
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1999.
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Studies in Asymmetric Catalysis: Lewis Base catalyzed/Lewis Acid Mediated Aldol Reactions of Ketone- and Amide Derived Nucleophiles
Additionally, the use of the silicon tetrachloride---chiral phosphoramide system has proven a competent catalyst for highly selective vinylogous aldol reactions between dienolates derived from a variety of alpha,beta-unsaturated carbonyl compounds to aldehydes. These reactions provided high levels …
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Studies in Asymmetric Catalysis. Part I. Lewis Base-Catalyzed Aldol Additions. Part II. Bis(oxazoline)palladium(ii)-Catalyzed Cyclopropanation
A variety of bis(oxazoline)palladium(II) complexes were prepared and tested in the cyclopropanation of ethyl (E)-cinnamate with diazomethane. Although an enantioselective process was never realized, effects of substitution on the ligand, catalyst loading studies, and other investigations led to a …
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Studies in Asymmetric Catalysis: Lewis Base Catalyzed, Enantioselective Addition of Trimethylsilyl Cyanide, Trimethylsilyltrifluoromethane, and Glycolate-Derived Silyl Ketene Acetals to Aldehydes
A catalytic system involving silicon tetrachloride and a chiral, Lewis basic bisphosphoramide catalyst is effective for the addition of glycolate-derived silyl ketene acetals to aldehydes. The sense of diastereoselectivty could be modulated by changing the size of the substituents on the silyl …
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Applications of planar-chiral phosphaferrocene-oxazolines in asymmetric catalysis and enantioselective desymmetrization by carbon nucleophiles in the presence of chiral ligands
… applied to several transition metal-catalyzed asymmetric reactions. In Pd-catalyzed asymmetric allylic alkylations, it is established that the planar chirality of the phosphaferrocene, not the central chirality of the oxazoline subunit, is the dominant stereocontrol element. On the other hand, …
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The origin of remarkable chromatographic differences in novel azulenyl-1,5-diols and synthesis and use of phosphinine and phosphabarrelene ligands for asymmetric catalysis.
… but have shown promise as good ligands for asymmetric catalysis. Our group had previously synthesized a C₂-symmetric chiral bis-camphorphosphinine and the derived bis-camphorphosphabarrelene but neither had been tested as ligands for hydroformylation. In this work, optimization of the …
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ASYMMETRIC ORGANOCATALYTIC HENRY REACTION OF β–SUBSTITUTED α-KETO ESTERS VIA DYNAMIC KINETIC RESOLUTION
… a brief historical background and development of asymmetric catalysis. Particularly, the asymmetric organocatalysis is introduced in detail. Then the historical background and development of dynamic kinetic resolution are summarized, especially, those organocatalytic methods are introduced in …
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Development and Mechanistic Investigation of Indium(III)-Catalysed Hydrosilane Reduction of Imines
Asymmetric catalysis continues to be of utmost importance inter alia for the development of enantiomerically pure drugs. The application of computational methods in understanding how enantioselectivity is induced in specific reactions is a powerful time-saving tool for organic chemists. By …
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Design and Synthesis of Redox or Catalytically Active Artificial Metalloproteins Containing Non-Native Inorganic and Organometallic Complexes
… complexes into environmentally benign asymmetric catalysts, we have covalently attached metal complexes, such as ferrocene and manganese salen (Mn(Salen)) to the active sites of cytochrome c peroxidase (CcP) and sperm whale myoglobin (Mb) using cysteine residues. The new metalloproteins …
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The Syntheses of Bis-Guanidium Salts and Their Applications in Asymmetric Mukaiyama Type SN2 Alkylation Reactions
… centers and applied these catalysts in asymmetric catalysis of 1,4-dicarbonyl compounds via Mukaiyama type SN2 alkylation reactions. Firstly, a series of bis-guanidium salts were synthesized from commercially available and cheap chiral sources in 4 to 5 steps. For most of the …
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