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Showing 1 to 15 of 15 for “"Allylic alkylation"”.
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Ligand Dependent Regioselectivity in Palladium Mediated Allylic Alkylation
… dependent regioselectivity in palladium mediated allylic alkylation have been studied. It is believed that the regioselectivity is a result of nucleophilic attack trans to phosphorous when applying ligands wih different donor atoms. The regioselective memory effect (regioretention) was studied in …
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Sequential Enantioselective Iridium-Catalyzed Allylic Alkylation/Cope Rearrangement for the Construction of Acyclic γ-Tertiary or Quaternary Stereocenters
… enantioselective transition metal-catalyzed γ-allylic alkylation reactions have attracted increasing attention, albeit they are typically restricted to cyclic nucleophiles. A direct strategy to construct acyclic γ-allylated carbonyl derivates is underdeveloped due to the challenging regio- and …
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Synthesis of chiral phosphino-sulfoximines through phospha-Michael addition and their evaluation as 1,5-P,N-Ligand in asymmetric allylic alkylation
… 1,5-P,N-ligand in palladium-catalyzed asymmetric allylic alkylation. The key step of the synthesis of phosphino-sulfoximines is the introduction of the phosphorus via a phospha-Michael addition with enantiomerically pure vinyl sulfoximines using diphenylphosphine and a catalytic amount of …
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Synthesis and application of chiral dienes and chiral imidates as ligands for transition metal catalysis
… the best result was obtained in the asymmetric allylic alkylation with an imidate with a binaphtylbackbone: a moderate yield (53% yield) with an excellent selectivity (95% ee). Futhermore, we developed successfully hybrid imidate-phosphane ligands as a new type of P,N ligands. These ligands are …
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Novel Chiral Diamines and (S)-6-Chloronicotine Derivatives as Catalysts for Asymmetric Synthesis
… to benzaldehyde, and palladium-catalyzed allylic alkylation. Each of these catalysts has a nitrogen containing heterocycle and is synthesized in a few steps from commercially available materials, such as ephedrine and (S)-nicotine. Overall, the amino alcohol derivatives provided the best …
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Design and Development of New Catalytic Carbon-Carbon Bond Forming Reactions: I. N-Heterocyclic Carbene Based Catalytic Platform for Hauser-Kraus Annulations II. Copper-Catalyzed Selective Allylic Alkylation of Allylic Systems Using Grignard Reagents
… reaction and the formation of valuable allylic products from selective allylic alkylation reactions are described. First, the development of N-Heterocyclic carbene catalyzed benzannulation will be discussed based on a venerable reaction called the Hauser-Kraus annulation, developed in …
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Part I: The Study Of 2-Aryl-1,3-Dithiane Derivatives As Pronucleophiles In Palladium-Catalyzed Allylic Alkylation And Propellylation Part Ii: Ligand-Free Palladium-Catalyzed Allylic Amintion Of Hydrazone Derivatives Part Iii: Synthesis Of Criegee Intermediate Precursors
… as pronucleophiles in palladium-catalyzed allylic alkylation and propellylation to access skeletally diverse aryl alkyl ketone cores. Allylic carbonate and [1.1.1]propellane electrophiles successfully couple with in situ generated 2-sodio-1,3-dithiane nucleophiles to afford the …
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Application of Pd Catalyzed Alkylation: Synthesis of Bicyclic Furans, Isoxazolines and New Cyclopentane Amino acid Analogs
… emphasis of this work is to utilize Pd catalyzed allylic alkylation to synthesize new heterocycles including furans, isoxazolines and new cyclopentane amino-acid analogs in an enantioselective manner. The stereochemical outcome of these reactions is influenced by desymmetrization catalyzed by …
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Decarboxylative Strategies in Cobalt and Metallaphotoredox Catalysis: Approaches to Aroylation, Allylation, and Strain-Driven Reactivity
… carbonyl compounds. Finally, a decarboxylative allylic alkylation using cobalt catalysis was developed, an area traditionally dominated by precious metals such as palladium. Together, these methodologies represent a significant advancement over existing methods and allow access to unprecedented …
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Palladium-katalysierte enantioselektive Synthese allylischer Thiocarboxylate und Palladium-katalysierte Deracemisierung allylischer Carbonate
… topic of this thesis is the palladium-catalyzed allylic alkylation of potassium thioacetate (KSAc) und potassium thiobenzoate (KSBz) with racemic cyclic and acyclic allylic esters having a symmetrically substituted carbon skeleton by using the Trost ligand. By this method the corresponding …
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Synthesis and applications of atropisomeric quinazolinone phosphine ligands
… including palladium-catalyzed asymmetric allylic alkylation, phosphine-catalyzed [3+2] cycloaddition of N-tosylimines with 2,3- butadienoate, and asymmetric intramolecular Heck reaction were performed. The 2-methyl group of this ligand series could be activated into the olefin form in the …
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The selective palladium-catalysed decarboxylative coupling of nucleophiles in the presence of propargylic electrophiles
… in a regio- and chemoselective manner via an allylic linker. The reaction is applied to a wide range of substrates and forms two C–C bonds and installs two all-carbon quaternary centres. Mechanistic studies to help deduce the mechanism of the reaction are described, which shows that by …
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Multivalent activation in temporary phosphate tethers: A new tether for small molecule synthesis
… demonstrated through the divalent activation of allylic C2-symmetric monocyclic phosphates. Within these systems, the temporary phosphate tether mediates a highly diastereoselective desymmetrization event via copper-mediated allylic alkylation. Studies were extended to include C 2-unsymmetric …
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The Development of Asymmetric Palladium-Catalysed Transformations Using Chiral Sulfonated Phosphine Ligands
… obtained for the asymmetric palladium-catalysed allylic alkylation reaction. Next, the thesis details work towards controlling the regioselectivity of the palladium-catalysed π-allyl reactions, by harnessing the directing abilities of the ligand’s anionic sulfonate group. One of the ligands …
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Palladium(II) catalyzed allylic C-H alkylation reactions
… discovery of the first palladium(II)-catalyzed allylic C-H alkylation reaction. Allylic alkylation has long been performed by palladium(0) catalysis with allylic oxygenate starting materials. In contrast, this method proceeds directly from the readily accessible, chemically robust a-olefin …