نتایج جستجو برای: heterogeneous oligomerization of olefins
تعداد نتایج: 21174884 فیلتر نتایج به سال:
The widely available carbonyl compounds react with Grignard reagents in the presence of diethyl phosphite to give the corresponding olefins in good to excellent yields: A range of conjugated dienes, terminal olefins, multisubstituted-alkenes and conjugated enynes could be readily obtained by the method in mild conditions.
Palladium catalyzed cross coupling reactions of a vinyl triflate intermediate and various alkenyl stannanes afforded trisubstituted Z-olefins stereoselectively in high yields. These olefins were then converted to the corresponding 9Z-retinoic acids via Horner-Emmons reaction and subsequent basic hydrolysis in excellent yields.
Neutral and cationic organoactinide complexes have been extensively studied in the past decade as catalysts for several organic transformations.1,2 Polymerization of alkenes,3,4 oligomerization,5,6 intermolecular hydroamination,7-9 and hydrosilylation of terminal alkynes,10 and 1,1-insertion of isonitriles into terminal alkynes11 comprise some of these processes. However, because of the high ox...
A method for Pd-catalyzed, aminoquinoline-directed arylation of vinylic C-H bonds with aryl iodides has been developed. This reaction represents a rare example of Pd-catalyzed vinylic C-H functionalization of unsubstituted acrylamide, allowing for the highly regio- and stereoselective preparation of Z-olefins. High tolerance to functional groups is observed with good yields and excellent select...
A regioselective [3 + 2] cycloaddition of benzofuranone type active olefins with allenoates catalyzed by trivalent phosphines has been developed, which provided an easy access to enriched functionalized spirocyclic benzofuranones. The reactions accommodated a number of benzofuranone type electron-deficient olefins and allenoates to give the desired 3-spirocyclopentane benzofuran-2-ones or 2-spi...
A gold(III)-catalyzed hydroarylation of different olefins is reported here. AuCl3 works as an excellent catalyst to mediate reactions between various heterocycles and electron deficient olefins and alkynes under mild conditions. This gold(III)-based method tolerates different functional groups such as aldehyde, carboxylic acid, nitrile, and is highly efficient. We have shown that some of these ...
Unsaturated fatty acid esters derived from seed oils undergo metathesis at the C=C bond to give new internal and terminal olefins of interest in chemical manufacturing. The key to realizing this industrial opportunity is the ability to deploy catalysts that tolerate functional groups and remain reactive towards internal olefins even at high conversions. Recent developments in catalyst and react...
Mechanistic Studies of Ethylene and α-Olefin Co-oligomerization Catalyzed by Chromium-PNP Complexes.
To explore the possibility of producing a narrow distribution of mid- to long-chain hydrocarbons from ethylene as a chemical feedstock, co-oligomerization of ethylene and linear α-olefins (LAOs) was investigated, using a previously reported chromium complex, [CrCl(3)(PNP(OMe))] (1, where PNP(OMe) = N,N-bis(bis(o-methoxyphenyl)phosphino)methylamine). Activation of 1 by treatment with modified me...
fischer-tropsch synthesis is a promising route for production of light olefins via co hydrogenation over transition metals. co is one of the most active metals for fischer-tropsch synthesis. some different variables such as preparation parameters and operational factors can strongly affect the selectivity of fischer-tropsch synthesis toward the special products. in the case of preparation varia...
Per-ARNT-Sim (PAS) domains are essential modules of many multi-domain signalling proteins that mediate protein interaction and/or sense environmental stimuli. Frequently, multiple PAS domains are present within single polypeptide chains, where their interplay is required for protein function. Although many isolated PAS domain structures have been reported over the last decades, only a few struc...
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