نتایج جستجو برای: copper catalysis

تعداد نتایج: 108411  

2014
Manuel Peifer Raphaëlle Berger Valerie W. Shurtleff Jay C. Conrad David W. C. MacMillan

An efficient route towards biologically relevant pentose derivatives is described. The de novo synthetic strategy features an enantioselective α-oxidation reaction enabled by a chiral amine in conjunction with copper(II) catalysis. A subsequent Mukaiyama aldol coupling allows for the incorporation of a wide array of modular two-carbon fragments. Lactone intermediates accessed via this route pro...

2009
Katerina Brychtova Barbora Slaba Lukas Placek Josef Jampilek Ivan Raich Jozef Csollei

The conditions for the C-N bond forming reaction (C-N coupling reaction) between α-bromocarboxylate and nitrogen-containing non-aromatic heterocyclic rings under heterogeneous copper(I) oxide catalysis are investigated in this paper. All the generated compounds were fully characterized by IR, NMR and MS spectroscopy. Ab initio/DFT calculations of partial charges on nitrogen atoms in all the dis...

2017

Metal Nanoparticles have attracted considerable attention because of their excellent electronic and optical properties. They have been used in many fields, such as displays, solar cells, touchscreens, sensors, and electromagnetic interference shielding [1]. However, for most of these applications, metal Nanoparticles with high electrical conductance are required. Compared with various other met...

Journal: :Organic & biomolecular chemistry 2013
M Nagarjuna Reddy K C Kumara Swamy

Dual copper catalysis, involving two different reactions, click (alkyne-azide) and carbon-oxygen bond formation (aryl iodide-secondary alcohol) in a single step, is reported. Synthesis of novel benzodioxines (benzodioxanes), benzoxazines, benzoxathiines and benzodioxepines, which feature benzo-condensed six or seven membered rings containing two hetero-atoms attached to a 1,2,3-triazole, is des...

2015
Bhagwan S Batule Ki Soo Park Moon Il Kim Hyun Gyu Park

We developed a simple but efficient method to synthesize protein-inorganic hybrid nanostructures with a flower-like shape (nanoflowers), which relies on sonication to facilitate the synthesis of the nanoflowers. With this technique, we synthesized nanoflowers containing laccase as a model protein and copper phosphate within 5 minutes at room temperature. The resulting laccase nanoflowers yielde...

Journal: :Accounts of chemical research 2002
Chao-Jun Li

This Account outlines the recent efforts of developing catalysis under the ambient conditions of air and water for synthetic purposes from the author's laboratory. The discussions are focused on catalytic reactions (mostly C-C bond formations) other than oxidations via late transition metals. It includes the following aspects: (1) copper-catalyzed C-C bond formations; (2) palladium-catalyzed C-...

Journal: :Angewandte Chemie 2016
Long Shao Ya-Hui Wang De-Yang Zhang Jie Xu Xiang-Ping Hu

A copper-catalyzed asymmetric [3+2] cycloaddition of 3-trimethylsilylpropargylic esters with either β-naphthols or electron-rich phenols has been realized and proceeds by a desilylation-activated process. Under the catalysis of Cu(OAc)2⋅H2O in combination with a structurally optimized ketimine P,N,N-ligand, a wide range of optically active 1,2-dihydronaphtho[2,1-b]furans or 2,3-dihydrobenzofura...

Journal: :Angewandte Chemie 2016
Kodai Kato Koji Hirano Masahiro Miura

A copper-catalyzed regioselective and stereospecific aminoboration of vinylsilanes with bis(pinacolato)diboron (pinB-Bpin) and hydroxylamines has been developed. In the presence of a CuCl/MeO-dppbz catalyst, the boryl group and amino group are incorporated at the β position and α position, respectively, and the corresponding β-boryl-α-aminosilanes are obtained with good diastereoselectivity. Th...

2016
Sadayuki Arimori Okiya Matsubara Masahiro Takada Motoo Shiro Norio Shibata

Difluoromethanesulfonyl hypervalent iodonium ylides 2 were developed as electrophilic difluoromethylthiolation reagents for a wide range of nucleophiles. Enamines, indoles, β-keto esters, silyl enol ethers and pyrroles were effectively reacted with 2 affording desired difluoromethylthio (SCF2H)-substituted compounds in good to high yields under copper catalysis. The reaction of allyl alcohols w...

Journal: :The Journal of biological chemistry 1972
D Klug J Rabani I Fridovich

Superoxide dismutase catalyzes the decay of 0~~, generated by pulse radiolysis. The enzymatic reaction was 6rst order with respect to enzyme and to 0~~ and the rate constant, which was 2.3 X lo9 M-' s-l at pH 7.0 and ZO-25”, was not much affected by pH, in the range 4.8 + 9.5. Boiling the enzyme or reversibly removing its copper prosthetic group caused loss of catalytic activity. EDTA had no ef...

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