نتایج جستجو برای: cu catalysts
تعداد نتایج: 92695 فیلتر نتایج به سال:
The explosively-growing applications of the Cu-catalyzed Huisgen 1,3-dipolar cycloaddition reaction between organic azides and alkynes (CuAAC) have stimulated an impressive number of reports, in the last years, focusing on recoverable variants of the homogeneous or quasi-homogeneous catalysts. Recent advances in the field are reviewed, with particular emphasis on systems immobilized onto polyme...
Catalytic synthesis of nonracemic P-chiral phosphine derivatives remains a significant challenge. Here we report Cu-catalyzed enantioselective arylation of secondary phosphine oxides with diaryliodonium salts for the synthesis of tertiary phosphine oxides with high enantiomeric excess. The new process is demonstrated on a wide range of substrates and leads to products that are well-established ...
An orthogonal set of Cu-catalysts for the selective mono-arylation of alkyl aryl diols using aryl iodides is presented. Picolinic acid ligated copper catalyst provided phenol O-arylation only, while alkyl aryl ethers are generated by ligand-free copper catalyst in the presence of 2 equivalents NaOt-Bu.
A series of stable acyclic aminals derived from L-(+)-aspartic acid were synthesized in excellent yields (up to 96%) and characterized by spectroscopic methods. They were applied as enantioselective catalysts in Henry reactions of nitromethane with various aldehydes in the presence of Cu(II) ions, affording the corresponding adducts in high yields (up to 90%) and enantioselectivities (up to 92%...
The direct oxidation of benzene into phenol using hydrogen peroxide has been achieved in the absence of any acid with Tp(x)Cu(NCMe) complexes as the catalysts. In the case of anthracenes as the substrates, valuable anthraquinones have been quantitatively obtained in the same manner.
This paper describes the utilization of skeletal Ni-based catalysts for steam reforming of ethanol to produce CO-free hydrogen, which could be superior in the application of fuel cells. Assistant metals play different roles in the reaction; Pt and Cu suppress the methanation and enhance H(2) production, while Co promotes the methanation.
[formula: see text] Chiral Cu(II) bisoxazoline (box) Lewis acids have been developed as catalysts of the Michael addition of enolsilanes to unsaturated ester derivatives. While enantioselection is stereoregular, the sense of diastereoselection is directly related to thioester enolsilane geometry: (E) enolsilanes give anti adducts and (Z) enolsilanes afford syn adducts. The size of the enolsilan...
The DNA G-quadruplex-binding porphyrin TMPyP4·Cu was found to form efficient hybrid catalysts for DNA-based asymmetric catalysis when bound to DNA G-quadruplexes. Nucleobase substitution experiments using human telomere-derived G-quadruplex sequences suggest binding of the porphyrin on the 3'-face.
Remarkably high and regular enantioselectivities are obtained in Friedel-Crafts alkylation reactions involving alpha'-hydroxy enone templates and Cu(II)-bis(oxazoline) complexes as catalysts. The simple elaboration of adducts provides a route to enantioenriched aldehydes, carboxylic acids, and ketones containing the pyrrole and indole frameworks.
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