نتایج جستجو برای: olefin

تعداد نتایج: 2960  

2001
Peter Burger Hans H. Brintzinger

207 Novel olefin-linked biscylopentadienylligands have been prepared by McMurry coupling reactions of benzoyland acetyl-cyclopentadienyl sodium. Reactions of the disodium salts with TiC1 4 or TiCl 3 • 3THF afford the alkene-bridged ansa-titanocene dichlorides. 13C-NMR shifts of the bridge carbon atoms do not indicate any interaction between the olefin 'IT-system and the metal.

Journal: :Organic & biomolecular chemistry 2015
Kaki Raveendra Babu Faiz Ahmed Khan

An efficient acid induced rearrangement of a tetrahalo-7,7-dimethoxybicyclo[2.2.1]heptenyl system leading to substituted indenones is reported. This domino reaction involves dehydration, olefin isomerization, ketal hydrolysis, [3,3]-sigmatropic rearrangement and dehydrohalogenation. The resultant vicinal dihalo olefin moiety in the efficiently generated indenone derivatives was utilized to tran...

Journal: :Organic & biomolecular chemistry 2012
Shen-Shuang Jin Hui Wang Ting-Shun Zhu Ming-Hua Xu

The design and development of an extraordinarily interesting new class of chiral sulfur-olefin hybrid ligands with remarkable structural simplicity were described. These unique sulfinamide-olefin ligands have been proved to be highly effective ligands in rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids to α,β-unsaturated carbonyl compounds (up to 99% yield and 98% ee).

Journal: :Journal of Synthetic Organic Chemistry, Japan 1970

Journal: :Nature Chemistry 2014

Journal: :Journal of the American Chemical Society 2012
Eduardas Skucas David W C MacMillan

The enantioselective α-vinylation of aldehydes using vinyl iodonium triflate salts has been accomplished via the synergistic combination of copper and chiral amine catalysis. These mild catalytic conditions provide a direct route for the enantioselective construction of enolizable α-formyl vinylic stereocenters without racemization or olefin transposition. These high-value coupling adducts are ...

2015
Cheng-Liang Zhu Jun-Shan Tian Zhen-Yuan Gu Guo-Wen Xing Hao Xu

An iron-catalyzed enantioselective and diastereoselective intramolecular olefin aminochlorination reaction is reported (ee up to 92%, dr up to 15 : 1). In this reaction, a functionalized hydroxylamine and chloride ion are utilized as nitrogen and chlorine sources, respectively. This new method tolerates a range of synthetically valuable internal olefins that are all incompatible with existing a...

Journal: :Journal of the American Chemical Society 2011
Koji Endo Robert H Grubbs

We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands that catalyze highly Z-selective olefin metathesis. A very simple and convenient procedure for the synthesis of such catalysts has been developed. Intramolecular C-H bond activation of the NHC ligand, promoted by anion ligand substitution, forms the appropriate chelate for stere...

Journal: :The Journal of organic chemistry 2012
Feng Xue Dongping Wang Xincheng Li Boshun Wan

An efficient rhodium/olefin-sulfoxide catalyzed asymmetric conjugate addition of organoboronic acids to a variety of nitroalkenes has been developed, where 2-methoxy-1-naphthyl sulfinyl functionalized olefin ligands have shown to be highly effective and are applicable to a broad scope of aryl, alkyl, and heteroaryl nitroalkenes.

Journal: :iranian journal of catalysis 2015
ali afshar ebrahimi sara tarighi

the catalytic cracking of a fuel oil over fluid catalytic cracking (fcc) catalyst has been investigated applying different additives. catalyst mixtures consisting of a equilibrium fcc catalyst (e-cat) blended with zsm-5, mcm-41 and mordenite additives were examined at the additive levels of 25 wt.%. the catalytic performance of the matrix was studied in a fixed bed micro-activity test unit (mat...

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