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Showing 1 to 20 of 63 for “"Reductive Elimination"”.
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Toward the photo-induced reductive elimination of halogens
… metal dimers as potential platforms for the reductive elimination of halogen. Early transition metals were explored with bis(alkylamido)phenylborane ligands. These systems did not demonstrate halogen elimination, but an interesting transition metal chemistry was developed for this ligand set. …
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Photochemical reductive elimination of halogen from transition metal complexes
… transition metal complexes that undergo halogen elimination when irradiated with UV and visible light. This chemistry is relevant for solar energy storage schemes in which simple substrates such as HX (X = Cl, Br, OH) can be split to H2 and X2 in thermodynamically uphill photocycles. The …
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Reductive elimination of alkylamines and ethers: reactions of bisphosphine-ligated palladium(II) complexes
The reductive elimination reactions detailed in this dissertation provide experimental insight into the mechanism of reductive elimination to form the C(sp3)-N bond of benzylamines and the C(sp3)-O bond of benzyl ethers. The stereochemical outcome of the reaction indicates an ionic pathway, but the …
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REDUCTIVE ELIMINATION OF (DPMS)PTIV COMPLEXES DERIVED FROM ISOMERIC 2-BUTENEs AND 2-BUTYNE (DPMS=DI(2-PYRIDYL)METHANE SULFONATE)
… readily oxidized to PtIV oxetanes, followed by reductive elimination to produce corresponding epoxides. A catalytic version of this reaction can potentially be achieved if decomposition of active species responsible for olefin substitution is avoided. Several attempts were made to solve this …
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Palladium-catalyzed reactions of ammonia, carbon monoxide, and cyanide
The reductive eliminations of primary arylamines from a series of bisphosphine-ligated arylpalladium(II) parent amido complexes countered several established trends. In contrast to arylamido and alkylamido complexes of the aromatic bisphosphines DPPF and BINAP, parent amido complexes did not form …
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New carbon-nitrogen bond-forming reactions of palladium
… alkene into a palladium-nitrogen bond and the reductive elimination of an alkylamine from a low-valent alkylpalladium amido complex. These reactions were previously proposed as steps in palladium catalyzed reactions, however, these are the first examples of isolated palladium complexes that …
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INTRAMOLECULAR CARBON-NITROGEN COUPLING FROM ISOLATED MONOHYDROCARBYL PALLADIUM(IV) COMPLEXES PREPARED USING H2O2 AS TERMINAL OXIDANT
… were synthesized, oxidized with H2O2, and the reductive elimination of the high oxidation state Pd(IV, d6) containing species monitored. N-R-2-aminobiphenyl – derived substrates with electron donating groups (R = H, Me, Et) readily form carbazoles at room temperature without formation of …
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Mechanistic studies on palladium-catalyzed C-N cross-coupling reaction
… and diarylamine coupling partners. The rates of reductive elimination for catalysts based on the biaryl ligands XPhos, CyJohnPhos, CPhos, BrettPhos, RuPhos, and SPhos were evaluated. Analogues of SPhos demonstrated that electron-donation of the lower aryl group is key to the stability of the …
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New reactivity and selectivity in transition metal-catalyzed C-C and C-N bond forming processes
… ligands in facilitating challenging reductive elimination processes. Chapter 4. Mechanistic Studies on the Aryl-Trifluoromethyl Reductive Elimination from Pd(II) Complexes Based on Biarylphosphine Ligands A series of monoligated (L)Pd(Ar)(CF₃) (L = dialkyl biarylphosphine) have been …
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The Pd-catalyzed fluorination of (hetero)aryl bromides and triflates
… chapter details mechanistic work regarding the reductive elimination of electron-rich aryl fluorides from L-Pd(Ar)F species. An unexpected dearomatization/arylation process of Pd(II) complexes bearing bulky biaryl phosphines was discovered, resulting in ligand arylation during the catalytic …
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Catalytic enantioselective synthesis of oxindoles and benzofuranones bearing a quaternary stereocenter and reactions of palladium bisphosphine complexes relevant to catalytic C-C bond formation
… the cross-coupling of alkyl electrophiles. The reductive elimination of H-X from bisphosphine palladium-hydride complexes is also discussed. The discovery that (P(t-Bu)₃)₂PdHCl undergoes facile reductive elimination in the presence of Cy₂NMe, while (PCy₃)₂PdHCl does not, is explained using X-ray …
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Zirconium-mediated alkyene-aldehyde coupling, rhodium-catalyzed alkene hydrothiolation, and copper-catalyzed alkyne hydroarylation: Reaction development and mechanistic investigations
… followed by migratory insertion, and finally reductive elimination. The regiodivergence in the reaction is a result of the selectivity for the migratory insertion. The anti-Markovnikov reaction undergoes a Rh–H insertion, followed by Rh–S reductive elimination, while the Markovnikov-selective …
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Development of new transition metal-catalyzed carbon-fluorine, carbon-nitrogen, and carbon-carbon bond forming processes
… The preference of conducting [beta]-hydrogen elimination rather than reductive elimination from the trans-LPd(vinyl)F complex, which is generated predominantly due to the trans-effect, caused the poor regioselectivity of the fluorination reaction under TESCF₃-free conditions. An in situ ligand …
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Synthesis and Physical Investigation of some Organotellurium Compounds
… The compounds show stability toward the reductive elimination of alkyl halides in solutions such as CHC13, DMSO and DMF. The idea of association of the telluronium salts is now firmly established, and is supported by mass spectral and molecular weight data. 1H, 125Te and 13C NMR spectral …
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Design of New, More Stable, Precursors to Organopalladium(II) Complexes and Methods for the Palladium-Mediated Late-Stage Diversification of Pharmaceuticals
… aryl–trifluoromethyl cross-coupling reactions, reductive elimination is often the rate-limiting step. Stoichiometric studies of reductive elimination have proved effective in evaluating the ability of various ligands to facilitate this challenging elementary step. However, the difficulty of …
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High Valent Palladium Complexes and Their Role in C-C and C-X Bond Formation Chemistry.
… We were able to realize the C-C bond reductive elimination from a monomethyl Pd complexes with the ligand of N,N&rsquo-di-tBu-2,11-diaza[3,3](2,6)pyridinophane (tBuN4), which resembled the early step of methane oligomerization. To further study this process, we modified the tBuN4 by …
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Palladium-mediated C–H Functionalization of Aliphatic Amines via High Valent Palladium(IV) Intermediates
… intermediates capable of undergoing a variety of reductive elimination pathways to afford a diverse range of functionalized products. Hypervalent iodine(III) reagents were initially investigated as oxidants in the development of a Pd-catalyzed intramolecular γ C–H amination process to form …
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Development of new catalytic transformations and reagents for the construction of C-N and C-S bonds
… through studies of the transmetallation and reductive elimination steps of the reaction, including the first demonstration of reductive elimination from an arylpalladium isocyanate complex to produce an aryl isocyanate. Chapter 2. Palladium-Catalyzed Synthesis of N-Aryl Carbamates. An …
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Design of Reagents and Ligands for Direct Palladium-Catalyzed C(sp³)–H Functionalization of Aliphatic Carboxylic Acids
… a broad range of hydroxy acids via direct C–OH reductive elimination. Chapter 4 details a one-step protocol for accessing γ-lactones via challenging distal C–H activation, in which a new β-alanine derived ligand enabled functionalization of previously inaccessible substrate scaffolds. Finally, …
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Carbon-trifluoromethyl bond forming reactions and palladium-catalyzed cyanation of (hetero)aryl halides
… for transmetallation. In conjunction with reductive elimination studies, this led to the development of the first system for the trifluoromethylation of aryl chlorides. Chapter 2 A method for the oxidative trifluoromethylation of (hetero)aryl boronic acids is reported. Bench top setup and …
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