نتایج جستجو برای: olefins
تعداد نتایج: 2875 فیلتر نتایج به سال:
A stereoselective synthesis of anti-1,2-diols has been developed using a multitasking Ru catalyst in an assisted tandem catalysis protocol. A cyclometalated Ru complex catalyzes first a Z-selective cross-metathesis of two terminal olefins, followed by a stereospecific dihydroxylation. Both steps are catalyzed by Ru, as the Ru complex is converted to a dihydroxylation catalyst upon addition of N...
The gold-catalyzed intermolecular hydroalkylation of olefins with β-ketoesters represents a conceptually attractive and useful synthetic tool; however, it has been scarcely applied, remaining a challenge for chemists. The aim of the current study was to investigate the addition of these 1,3-diketo-compounds to alkenes under gold catalysis conditions, in order to establish the electronic and ste...
Ti(IV)-salan 4 catalyzes the diastereo- and enantioselective monoepoxidation of conjugated dienes using 30% H2O2 at rt or below even in the presence of other olefins and adjacent stereocenters. Its enantiomer, ent-4, provides access to the opposite diastereomer or enantiomer. The resultant chiral allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well a...
A solution to the classic unsolved problem of olefin hydromethylation is presented. This highly chemoselective method can tolerate labile and reactive chemical functionalities and uses a simple set of reagents. An array of olefins, including mono-, di-, and trisubstituted olefins, are all smoothly hydromethylated. This mild protocol can be used to simplify the synthesis of a specific target or ...
A two-dimensional nanolayered polyoxomolybdate, [4,4´-H2bipy] [Mo7O22].H2O (1), where 4,4´-bipy = 4,4´-bipyridine, was prepared and characterized by FT-IR and atomic absorption spectroscopies, transmission electron microscopy (TEM), X-ray single crystal and powder diffraction (XRD), and thermogravimetric analysis. The catalytic performance of 1 was assessed in the epoxidation of some olefins em...
CONSPECTUS: Vicinal diamines are important structural motifs present in various biologically and chemically significant molecules. Direct diamination of olefins provides an effective approach to this class of compounds. Unlike well-established oxidation processes such as epoxidation, dihydroxylation, and aminohydroxylation, direct diamination of olefins had remained a long-standing challenge an...
Ti-MCM-41 was synthesized at pH 3, 7 and 11. The titanium content was determined by AAS and found to be 4%, 3.2% and 4.5%, respectively. In order to increase the titanium content in Ti-MCM-41, Ti(IV) ions were grafted onto Ti-MCM-41 using TiCl4 in toluene and Ti(OBu)4 in ethanol. The incorporation of Ti was determined to be 28% and 30%, respectively. The oxidation of olefins such as cyclopenten...
Abstract To utilize Cu-benzene-1,3,5-tricarboxylate (Cu-BTC) adsorbed lubricant oils in the self-lubricating field, adsorption properties of Cu-BTC on different 1-olefins must be clarified. In this work, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene were studied by Monte Carlo method experimentally. The limit for n-olefins was determined as 1-undecene isotherms. This sugges...
The evaluation of ruthenium olefin metathesis catalysts 4-6 bearing cyclic (alkyl)(amino)carbenes (CAACs) in the cross-metathesis of cis-1,4-diacetoxy-2-butene (7) with allylbenzene (8) and the ethenolysis of methyl oleate (11) is reported. Relative to most NHC-substituted complexes, CAAC-substituted catalysts exhibit lower E/Z ratios (3:1 at 70% conversion) in the cross-metathesis of 7 and 8. ...
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