scholarly journals Carbocation catalysed ring closing aldehyde–olefin metathesis

2018 ◽  
Vol 54 (92) ◽  
pp. 12982-12985 ◽  
Author(s):  
Shengjun Ni ◽  
Johan Franzén
Keyword(s):  
Olefin Metathesis ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
Low Catalyst Loading

4-Phenylphenyl-diphenylmethylium tetrafluoroborate catalyses a rare high yielding intramolecular aldehyde–olefin metathesis of enals under mild reaction conditions and low catalyst loading.

Y(OTf)3-catalyzed Phosphorylation of 2H-Chromene Hemiacetals with P(O)-H compounds to 2-Phosphorylated 2H-Chromenes

2021 ◽  
Author(s):  
Long Chen ◽  
Shi-Lu Zheng ◽  
Yun-Xiang Zou ◽  
Zhong Wen ◽  
Jiafu Lin ◽  
...  
Keyword(s):  
Catalyst Loading ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
Low Catalyst Loading

Facile synthesis of 2-phosphorylated 2H-chromenes has been accomplished herein via a Y(OTf)3-catalyzed dehydrative coupling of 2H-chromene hemiacetals with P(O)-H compounds. This protocol features low catalyst loading, mild reaction conditions, broad...

Silica-supported ZnCl2 — A highly active and reusable heterogeneous catalyst for the one-pot synthesis of dihydropyrimidinones–thiones

2007 ◽  
Vol 85 (3) ◽  
pp. 197-201 ◽  
Author(s):  
Raman Gupta ◽  
Monika Gupta ◽  
Satya Paul ◽  
Rajive Gupta
Keyword(s):  
Zinc Chloride ◽  
Biginelli Reaction ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
One Pot ◽  
Highly Active ◽  
Chloride Catalyst ◽  
Biginelli Compounds ◽  
The One ◽  
Low Catalyst Loading

A novel silica-supported zinc chloride catalyst was prepared and investigated for the Biginelli reaction. The key features of the catalyst include rapid reaction with 100% conversion of aldehyde, good catalyst recyclability, and high stability under the reaction conditions (passes hot filtration test successfully). A low catalyst loading (12 mol% of ZnCl2) was required to achieve a quantitative reaction. Other catalysts such as SiO2–AlCl2, SiO2–AlCl2–ZnCl2 were also prepared and their activity was compared with SiO2–ZnCl2 for the Biginelli reaction.Key words: silica gel, zinc chloride, Biginelli compounds, heterogeneous catalysis, reusability.

scholarly journals Synthesis and Catalytic Applications of Ultrasmall Copper Nanoparticles Using Aloe Vera Plant Extract

2020 ◽  
Author(s):  
Rajagopal Ramkumar ◽  
Shradha Sapru ◽  
Panthalattu Parambil Archana
Keyword(s):  
Catalytic Activity ◽  
Copper Nanoparticles ◽  
Plant Extract ◽  
Aloe Vera ◽  
Catalyst Loading ◽  
Water Medium ◽  
Reaction Conditions ◽  
Three Component Reaction ◽  
Catalytic Applications ◽  
Low Catalyst Loading

<div>An extract of <i>Aloe Vera</i> acts as a powerful reducing agent for the synthesis of ultrasmall copper nanoparticles (CuNPs) in water medium. The prepared copper nanoparticles are characterized by XRD, HRTEM and UV-Vis analysis. The diameter of the prepared nanoparticle is less than 5 nm. The catalytic activity of CuNPs has been successfully evaluated for the three-component reaction to synthesize 1,2,3-triazoles and chalcone tethered 1,2,3-triazoles with low catalyst loading and under mild reaction conditions. These triazoles are further utilized for the synthesis of dihydropyrazines.</div>

Highly Enantioselective Michael Addition of Cyclic Diketones to β,γ-Unsaturated α-Keto Esters Catalyzed by Squaramide Organocatalyst

Synthesis ◽  
2022 ◽  
Author(s):  
Zhi-Wei Ma ◽  
Chuan-Chuan Wang ◽  
Quan-Jian Lv ◽  
Xiao-Pei Chen ◽  
Ai-Qin Li ◽  
...  
Keyword(s):  
Michael Addition ◽  
Large Scale ◽  
Catalyst System ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
Keto Esters ◽  
Bicyclic Compounds ◽  
Asymmetric Michael Addition ◽  
High Yields ◽  
Low Catalyst Loading

AbstractA new tertiary amine-squaramide organocatalyst has been developed and applied to the asymmetric Michael addition of cyclic diketones to β,γ-unsaturated α-keto esters. The catalyst system performed well with a low catalyst loading of 1 mol% under mild reaction conditions. A series of synthetically and pharmaceutically useful chiral bicyclic compounds were obtained in high yields (up to 97%) with excellent enantioselectivities (up to 99 % ee). Furthermore, this catalytic system can be used efficiently in large-scale reactions with the yields and enantioselectivities being maintained.

Fast Olefin Metathesis at Low Catalyst Loading

2012 ◽  
Vol 18 (40) ◽  
pp. 12845-12853 ◽  
Author(s):  
Lars H. Peeck ◽  
Roman D. Savka ◽  
Herbert Plenio
Keyword(s):  
Olefin Metathesis ◽  
Catalyst Loading ◽  
Low Catalyst Loading

scholarly journals Synthesis and Catalytic Applications of Ultrasmall Copper Nanoparticles Using Aloe Vera Plant Extract

2020 ◽  
Author(s):  
Rajagopal Ramkumar ◽  
Shradha Sapru ◽  
Panthalattu Parambil Archana
Keyword(s):  
Catalytic Activity ◽  
Copper Nanoparticles ◽  
Plant Extract ◽  
Aloe Vera ◽  
Catalyst Loading ◽  
Water Medium ◽  
Reaction Conditions ◽  
Three Component Reaction ◽  
Catalytic Applications ◽  
Low Catalyst Loading

<div>An extract of <i>Aloe Vera</i> acts as a powerful reducing agent for the synthesis of ultrasmall copper nanoparticles (CuNPs) in water medium. The prepared copper nanoparticles are characterized by XRD, HRTEM and UV-Vis analysis. The diameter of the prepared nanoparticle is less than 5 nm. The catalytic activity of CuNPs has been successfully evaluated for the three-component reaction to synthesize 1,2,3-triazoles and chalcone tethered 1,2,3-triazoles with low catalyst loading and under mild reaction conditions. These triazoles are further utilized for the synthesis of dihydropyrazines.</div>

Regio- and stereoselective hydrosilylation of alkynes catalyzed by SiO2 supported Pd–Cu bimetallic nanoparticles

2017 ◽  
Vol 19 (11) ◽  
pp. 2535-2540 ◽  
Author(s):  
Jia-wei Zhang ◽  
Guo-ping Lu ◽  
Chun Cai
Keyword(s):  
Bimetallic Nanoparticles ◽  
Catalyst Loading ◽  
Terminal Alkynes ◽  
Reaction Conditions ◽  
Bimetallic Nanoparticle ◽  
Low Catalyst Loading ◽  
Supported Pd ◽  
Nanoparticle Catalyst

An efficient, recyclable Pd–Cu bimetallic nanoparticle catalyst has been prepared, which exhibits superior activity and selectivity toward the hydrosilylation of internal and terminal alkynes under mild reaction conditions with a low catalyst loading.

Ruthenium Complexes Bearing Two N-Heterocyclic Carbene Ligands in Low Catalyst Loading Olefin Metathesis Reactions

2010 ◽  
Vol 29 (13) ◽  
pp. 3007-3011 ◽  
Author(s):  
Xavier Bantreil ◽  
Rebecca A. M. Randall ◽  
Alexandra M. Z. Slawin ◽  
Steven P. Nolan
Keyword(s):  
Olefin Metathesis ◽  
Ruthenium Complexes ◽  
Catalyst Loading ◽  
Carbene Ligands ◽  
Metathesis Reactions ◽  
Low Catalyst Loading

scholarly journals Synthesis of benzodiazepines catalyzed by CoFe2O4@SiO2-PrNH2 nanoparticles as a reusable catalyst

2017 ◽  
Vol 72 (7) ◽  
pp. 497-503 ◽  
Author(s):  
Naiereh Sadat Miri ◽  
Javad Safaei-Ghomi
Keyword(s):  
Catalyst Loading ◽  
Reusable Catalyst ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
Reaction Conditions ◽  
Efficient Catalyst ◽  
Wide Range ◽  
Low Catalyst Loading

AbstractCoFe2O4@SiO2-PrNH2 nanoparticles have been used as an efficient catalyst for the preparation of benzodiazepines by multi-component reactions of 1,2-phenylenediamine, dimedone, different aldehydes or Meldrum’s acid and isocyanides. This method provides several advantages including mild reaction conditions, the applicability to a wide range of substrates, the reusability of the catalyst and low catalyst loading.

Low catalyst loading enabled organocatalytic synthesis of chiral bis-heterocyclic frameworks containing pyrazole and isoxazole

2021 ◽  
Author(s):  
BanniPreet Kaur ◽  
Vivek Sharma ◽  
Subash Chandra Sahoo ◽  
Swapandeep Singh Chimni
Keyword(s):  
Michael Addition ◽  
Addition Reaction ◽  
Catalyst Loading ◽  
Pyrazole Derivatives ◽  
Michael Addition Reaction ◽  
Reaction Conditions ◽  
Low Catalyst Loading

A low-catalyst loading Michael addition reaction of pyrazolyl nitroalkenes with 1,3-dicarbonyl derivatives has been carried out under mild reaction conditions to afford 4-substituted pyrazole derivatives in 60-87% yields and 82-96%...

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