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Showing 1 to 20 of 38 for “"phosphine ligand"”.
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The synthesis and applications of a biaryl-based asymmetric phosphine ligand
… asymmetric biaryl backbone of a dialkylbiphenyl phosphine ligand was developed, synthesized, and resolved. The application of the chiral phosphine ligand to the asymmetric Suzuki-Miyaura cross-coupling reaction was also investigated. This phosphine ligand has yielded promising results in the …
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Control of selectivity in palladium-catalysed cross-coupling reactions using a sulfonated phosphine ligand
… on members of the privileged dialkylbiarylphosphine ligand class, specifically sSPhos, which is the commercially available sulfonated variant of SPhos. The first part investigates the use of this ligand to impart site-selectivity in the cross-coupling of 3,4-dichloroarenes containing an …
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Effect of Phosphine Ligand Substitution on the Structures, Reactivities, and Ligand Rearrangements in Organotriosmium Compounds
… and PCy3 0.24 (4) min -1. The more donating ligands have slower rates of polymerization as illustrated by the fact that L = PEt3 and PCy3 have essentially the same rate constant and similar pKa's (8.69 vs. 9.70) but quite different cone angles (132° vs. 162°).
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The Synthesis and Application of a Chiral Sulfonated Phosphine Ligand to Asymmetric Transition-Metal Catalysis
… describes the synthesis of a chiral sulfonated phosphine ligand, sSPhos, in its enantiopure form and its subsequent application in asymmetric transition-metal catalysis. sSPhos is a dialkylbiaryl phosphine ligand bearing a sulfonate group. This sulfonate group can engage in non-covalent …
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"Low-valent early transition metal complexes stabilized by the chelating tripod phosphine ligand ( t-butyl)tris((dimethylphosphino)methyl);silane (""trimpsi"")"
… extended through the use of a new tridentate phosphine ligand, Bu$\sp{\rm t}$Si(CH$\sb2$PMe$\sb2$)$\sb3$, or ""trimpsi"". The starting materials (trimpsi)TiCl$\sb3$(thf), (trimpsi)VCl$\sb3$(thf), (trimpsi)CrCl$\sb3$, and (trimpsi)ZrCl$\sb4$(dme) have been used to prepare new carbonyl, arene, …
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I. Multicatalysis: Development of a BiOTf₃-catalyzed Nucleophilic Addition/Hydrofunctionalization Reaction in the Synthesis of Complex Heterocycles; . . .
… - and examining its reactivity. The pivalate ligand, in comparison to acetate, does not yield faster rates of C-H activation, but instead stabilizes the resting state of the catalyst against decomposition to inactive palladium species. An experimentally supported rationale for the superiority …
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Synthesis, characterization, and reactivity studies of iridium complexes bearing the ligand diphenylphosphidoboratabenzene
… square planar complexes bearing the anionic phosphine ligand diphenylphosphidoboratabenzene (DPB) are described. Reactivity studies show a rate enhancement for the oxidative addition of a substituted benzyl bromide and Me₃SnBr with DPB as a ligand in place of triphenylphosphine. Two products …
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Chiral Organometallic osmium(VI) Nitrido Complexes
… aldehydes and ketones respecively. The bidentate phosphines dppe and (S,S)-CHIRAPHOS bind with the Os-Cr heterobimetallic complexes. Exposure to oxygen allows the chromium to oxidize the phosphine ligand producing phosphine oxide and the starting heterobimetallic complex.
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Nickel-catalyzed cross-couplings of unactivated secondary and tertiary alkyl halides and photoinduced copper-mediated asymmetric C-N cross-couplings
… carbazoles, with the use of a monodentate chiral phosphine ligand, are presented. The methodology is then extended to secondary [alpha]-haloamides, including [alpha]-halolactams, which are found to afford very promising yields and enantioselectivities.
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Nickel-catalyzed intermolecular reductive couplings of alkynes and aldehydes ; Enantioselective synthesis of (-)-terpestacin and structural revision of siccanol using catalytic stereoselective fragment couplings and macrocyclizations
… regioselectivity were strongly dependent on the phosphine ligand, but the allylic alcohols formed were invariably the products of cis addition to the alkyne. [Image] ... II. Enantioselective Synthesis of (-)-Terpestacin and Structural Revision of Siccanol Using Catalytic Stereoselective Fragment …
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The development of palladium-catalyzed cross-coupling reactions of allylic silanolate salts with aromatic bromides
… takes place at 85 °C under “ligand-less’ conditions in 1,2-dimethoxyethane with allylpalladium chloride dimer (2.5 mol %) to afford 73–95% yields of the allylation products. Both electron-rich and sterically hindered bromides reacted smoothly, whereas electron-poor bromides …
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Ligand design principles for perfecting stereoretention in Suzuki-Miyaura cross-coupling of unactivated CSP3 boronic acids
… By systematically studying the effect of the phosphine ligand on the outcome of a model Csp3 cross-coupling reaction, we have elucidated ligand steric and electronic design principles for maximizing stereoretention. These ligand design principles are applicable across different reaction …
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Development of transitional metal-catalyzed reactions for organic synthesis
… is based on a phenanthrene-substituted biaryl phosphine ligand. Utilizing this ligand, a number of tetra-ortho-substituted biaryls were synthesized in good to excellent yields. Chapter 2. A procedure for the arylation of methyl and cyclic ketone enolates with o-halonitroarenes was developed. An …
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Synthesis and application of sterically flexible and water-soluble phosphine ligands in palladium catalysis
… on the design and synthesis of water-soluble phosphines for application in aqueous and biphasic palladium catalysis. Our group, through collaboration with the Dixon and Rogers groups, seeks also to better understand how phosphine ligand structure influences catalysis in order to design more …
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Ruthenium complexes as potential aqueous romp catalysts
… a novel complex containing the water soluble phosphine ligand trist(hydroxymethyl)phosphine P(CH2OH)3. Its synthesis and characterisation are described and its physical properties compared and contrasted to analogous compounds of platinum and palladium. Its peculiar properties are ascribed to …
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Recent advances in palladium-catalyzed carbon-carbon and carbon-boron bond forming processes
… derived from palladium precatalysts and monophosphine ligands for the Suzuki-Miyaura cross-coupling reaction of heteroaryl boronic acids and esters has been developed. This method allows for the preparation of a wide variety of heterobiaryls in good to excellent yields and displays a high …
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Chiral phosphine synthesis by the application of directed metallation
… to the synthesis of novel chiral ditertiary phosphines. Thus, an ortho lithiation of N,N,N',N'-tetramethyl-P-phenylphosphonic diamide (10) led to the interesting primary phosphine, 2-(diphenylphosphino)phenylphosphine (14), after elaboration of the phosphonic diamide directing group. This …
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Use of water-soluble phosphine ligands in heterogeneous hydroformylation catalysis : application to long-chain 1-alkenes
The two-phase rhodium-tri(m-sulfonatophenyl)phosphine (Rh-TPPTS) system for the hydroformylation of 1-octene, 1-decene, and 1-dodecene to the corresponding aldehydes, has been investigated. Due to the two distinct phases - the catalytic species in the aqueous phase and the products and reactants in …
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Palladium-catalyzed C-N and C-O cross-coupling reactions
… reaction utilized catalysts based on two biaryl phosphine ligands, which were developed via kinetics-based mechanistic analysis and rational design. These studies led to the first example of catalyst based on a hybrid (alkyl)aryl biaryl phosphine ligand that provides better results that its …
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The synthesis and characterization of novel rhodium alkenyl complexes and rhodacycloalkanes
… rhodacycloalkenes had been formed. The rhodium phosphine precursors Cp*RhCh(PR3) (PR3 = PPh3, PMePh2, PMe2Ph) were prepared and reacted with the di-Grignard reagents MgBr-(CH2)n-MgBr (n = 7, 8, 9) to form a series of medium-sized rhodacycloalkanes that were larger than any synthesized …
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