نتایج جستجو برای: alkene
تعداد نتایج: 1831 فیلتر نتایج به سال:
Organoiron Complexes, Olefin Isomerization, 1,2-Dimethoxyethylene Displacement of 2-methvlpropene from [Fp(Me2C = CH2)]BF4 (Fp = (/?5-C5H5)Fe(CO)2) by Z-1,2-dimethoxyethylene (Z-DME) gives [Fp(Z-DME)]BF4. Displacement by E-1,2dimethoxyethylene (E-DME), in contrast, does not give the expected complex of E-DME, but rather the complex of the Z-alkene. A mechanism involving scission of the C = C bo...
Unsupported thiolate-capped palladium nanoparticle catalysts are found to be highly substrate-selective for alkene hydrogenation and isomerization. Steric and poisoning effects from thiolate ligands on the nanoparticle surface control reactivity and selectivity by influencing alkene adsorption and directing either di-σ or mono-σ bond formation. The presence of overlapping p orbitals and α proto...
Here we describe the metathesis reactions of a strained eight-membered ring that contains both alkene and alkyne functionality. We find that the alkyne metathesis catalyst produces polymer through a ring-opening alkyne metathesis reaction that is driven by the strain release from the monomer. The strained monomer provides unusual reactivity with ruthenium-based alkene metathesis catalysts. We i...
Pd-catalyzed allylic relay Suzuki cross-coupling reactions of secondary alkyl tosylates, featuring a sterically-hindered oxidative addition and precise control of β-hydride elimination, are reported. The identification of a linear free energy relationship between the relative rates of substrate consumption and the electronic nature of the substrate alkene suggests that the oxidative addition re...
In the title compound, C(14)H(10)Cl(2)O(2)S, the product of a base-catalyzed condensation followed by deca-rboxylation of the carboxyl-ate group of the sulfonyl derivative, the configuration of the alkene unit is E. The torsion angle between the alkene unit and the 2,6-dichloro-phenyl ring system is -40.8 (3)°. The dihedral angle between the rings is 80.39 (7)°.
Cobalt-catalyzed carboxyzincation reactions employing carbon dioxide and zinc metal powder are developed. By using alkynes as substrates, regio- and stereodefined (Z)-β-zincated acrylates are provided. The corresponding alkenylzinc moiety can be converted to various substituents, affording multisubstituted acrylic acids. Furthermore, by adding electron-deficient alkene to the reaction system, t...
A short entry to substituted azocanes by a Rh-catalyzed cycloaddition-fragmentation process is described. Specifically, exposure of diverse N-cyclopropylacrylamides to phosphine-ligated cationic Rh(I) catalyst systems under a CO atmosphere enables the directed generation of rhodacyclopentanone intermediates. Subsequent insertion of the alkene component is followed by fragmentation to give the h...
In the presence of an alkene, three different modes of photocycloaddition with benzene derivatives can occur; the [2 + 2] or ortho, the [3 + 2] or meta, and the [4 + 2] or para photocycloaddition. This short review aims to demonstrate the synthetic power of these photocycloadditions.
The stereochemical course of the amidopalladation of alkenes has important implications for the development of enantioselective Pd-catalyzed "Wacker-type" oxidative amidation of alkenes. We have recently shown that the addition of base (Na2CO3) can alter the stereochemical course of amidopalladation in the (IMes)Pd(TFA)2(H2O)-catalyzed aerobic oxidative amidation of alkene. In this study, the m...
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