نتایج جستجو برای: olefins
تعداد نتایج: 2875 فیلتر نتایج به سال:
Ruthenium-based olefin metathesis catalysts bearing dithiolate ligands have been recently employed to generate olefins with high E-selectivity (>99% E) but have been limited by low to moderate yields. In this report, 1H NMR studies reveal that a major contributing factor to this low activity is the extremely low initiation rates of these catalysts with trans olefins. Introducing a 2-isopropoxy-...
A long-sought goal in electrochemistry has been the observation of the intermediate, presumably the anion radical, produced in the electrohydrodimerization (EHD) of acrylonitrile (AN). The EHD of activated olefins is an important class of electroorganic reactions, especially because a commercial process for adiponitrile synthesis is based upon the EHD of a~rylonitrile.l-~ A number of studies of...
We describe a novel, integrated multi-step process for the partial oxidation of alkanes to alcohols, ethers or olefins using O2 as oxidant. The sequential transformations are (1) alkane bromination to alkyl bromide(s) and HBr, (2) reaction of this mixture with solid metal oxide (MO) to neutralize the HBr and to generate oxygenated products or olefins plus solid metal bromide, and (3) oxidation ...
Photocatalytic enantioselective epoxidation of terminal olefins using a mononuclear non-heme chiral manganese catalyst, [(R,R-BQCN)MnII]2+, and water as an oxygen source yields epoxides with relatively high enantioselectivities (e.g., up to 60% enantiomeric excess). A synthetic mononuclear non-heme chiral Mn(IV)-oxo complex, [(R,R-BQCN)MnIV(O)]2+, affords similar enantioselectivities in the epo...
Palladium(II) complexes containing phosphine donor ligands derived from naphthyl(diphenyl)phosphine were synthesized and characterized by NMR and elemental analysis. The complexes were studied as catalyst precursors in the methoxycarbonylation reaction of several aromatic and aliphatic olefins under mild conditions. The catalysts reported high chemoselectivities (over 96%) and regioselectivitie...
Epoxides are an important class of industrial chemicals that have been used as chemical intermediates. Catalytic epoxidation of olefins affords an interesting production technology. We found a widely usable green route to the production of epoxides: A silicotungstate compound, [gamma-SiW10O34(H2O)2]4-, is synthesized by protonation of a divacant, lacunary, Keggin-type polyoxometalate of [gamma-...
Alcohol synthesis is critical to the chemical and pharmaceutical industries. The addition of water across olefins to form primary alcohols (anti-Markovnikov olefin hydration) would be a broadly useful reaction but has largely proven elusive; an indirect hydroboration/oxidation sequence requiring stoichiometric borane and oxidant is currently the most practical methodology. Here, we report a mor...
Ph3PAuOTf can catalyze efficient intermolecular addition of phenols and carboxylic acids to olefins under relatively mild conditions.
Selenochromanes and analogues are conveniently prepared through a tandem homolytic addition/substitution sequence involving suitably substituted olefins.
2,4,6-Triphenylpyrylium cation encapsulated within zeolite Y promotes highly selective transformation of olefins to ketones with molecular oxygen, under visible light (lambda > 400 nm) irradiation at room temperature.
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید