نتایج جستجو برای: copper catalysis
تعداد نتایج: 108411 فیلتر نتایج به سال:
poly(4-vinylpyridine)-supported copper iodide nanoparticles is reported as a new, green and recyclable catalyst for the synthesis of aryl-14h-dibenzo [a-o] xanthenes under solvent-free conditions. this catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of their efficiency.
Despite a well-developed and growing body of work in copper catalysis, the potential of copper to serve as a photocatalyst remains underexplored. Here we describe a photoinduced copper-catalyzed method for coupling readily available racemic tertiary alkyl chloride electrophiles with amines to generate fully substituted stereocenters with high enantioselectivity. The reaction proceeds at -40°C u...
At the end of the Finnish epic Kalevala, the hero Väinämöinen sets sail into the heavens, leaving behind the mortal realm in a copper boat. Modern engineers seem to have taken this to heart: ships’ hulls are lined with materials based on copper, which inhibits the growth of bacteria, barnacles and other unwanted passengers. Väinämöinen’s vessel is just one example of how the reddish-brown lustr...
A copper complex has proven to be a potent catalyst for forming a C-B bond via diborylation of arynes and alkynes, affording vic-diborylarenes and vic-diborylalkenes with high efficiency. A boryl-substituted organocopper species, which is intermediately generated in the diborylation, has been found to be captured by a tin or a carbon electrophile, leading to three-component borylstannylation or...
2-Diazo-1-phenyl-2-((trifluoromethyl)sulfonyl)ethan-1-one (diazo-triflone) (2) is not only a building block but also a reagent. In this study, diazo-triflone, which was originally used for the synthesis of β-lactam triflones as a trifluoromethanesulfonyl (SO2CF3) building block under catalyst-free thermal conditions, is redisclosed as an effective electrophilic trifluoromethylthiolation reagent...
A catalyst is a substance that allows a chemical reaction to proceed at a faster rate than normally possible. Worldwide industry is dependent on catalysis to produce many products, such as plastics, hygiene products, and fertilizers. Precious metals like platinum and palladium are widely used in catalysis. These metals work very well due to their ability to accept and supply electrons (known as...
copper extraction from heap 3 low grade ore at sarchechmeh is limited due to its mixed composition (copper oxide and sulphide minerals). changing this heap to a bioheap could improve the copper recovery.
Global warming concern has dramatically increased interest in using CO2 as a feedstock for preparation of value-added compounds, thereby helping to reduce its atmospheric concentration. Here, we describe a dinuclear copper(I) complex that is oxidized in air by CO2 rather than O2; the product is a tetranuclear copper(II) complex containing two bridging CO2-derived oxalate groups. Treatment of th...
Colloidal or heterogeneous nanocatalysts can improve the range and diversity of Cu(I)-catalysed click reactions and facilitate catalyst separation and reuse. Catalysis by metal nanoparticles raises the question as to whether heterogeneous catalysts may cause homogeneous catalysis through metal ion leaching, since the catalytic process could be mediated by the particle, or by metal ions released...
A radical Smiles rearrangement strategy for allowing an unprecedented [3 + 2]/[3 2] carboannulation of dienynes with arylsulfonyl chlorides using cheap copper catalysis is described.
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