scholarly journals An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

2017 ◽  
Vol 13 ◽  
pp. 1717-1727 ◽  
Author(s):  
Carolina S García ◽  
Paula M Uberman ◽  
Sandra E Martín
Keyword(s):  
Microwave Irradiation ◽  
Aqueous Media ◽  
Coupling Reaction ◽  
Catalyst Loading ◽  
Coupling Reactions ◽  
Heck Coupling ◽  
Turnover Frequency ◽  
High Turnover ◽  
Aryl Bromides ◽  
Simple Product

Aqueous Mizoroki–Heck coupling reactions under microwave irradiation (MW) were carried out with a colloidal Pd nanocatalyst stabilized with poly(N-vinylpyrrolidone) (PVP). Many stilbenes and novel heterostilbenes were achieved in good to excellent yields starting from aryl bromides and different olefins. The reaction was carried out in a short reaction time and with low catalyst loading, leading to high turnover frequency (TOFs of the order of 100 h−1). The advantages like operational simplicity, high robustness, efficiency and turnover frequency, the utilization of aqueous media and simple product work-up make this protocol a great option for stilbene syntheses by Mizoroki–Heck reaction.

scholarly journals Palladium-Catalyzed Heck Coupling Reaction of Aryl Bromides in Aqueous Media Using Tetrahydropyrimidinium Salts as Carbene Ligands

Molecules ◽  
2010 ◽  
Vol 15 (2) ◽  
pp. 649-659 ◽  
Author(s):  
Sedat Yaşar ◽  
Emine Özge Özcan ◽  
Nevin Gürbüz ◽  
Bekir Çetinkaya ◽  
İsmail Özdemir
Keyword(s):  
Aqueous Media ◽  
Coupling Reaction ◽  
Heck Coupling ◽  
Carbene Ligands ◽  
Aryl Bromides ◽  
Palladium Catalyzed

Invited Review. A Combinatorial Approach to the Development of Environmentally Benign Organic Chemical Preparations

1999 ◽  
Vol 52 (2) ◽  
pp. 83 ◽  
Author(s):  
Christopher R. Strauss
Keyword(s):  
Hydrogen Transfer ◽  
Aldol Condensation ◽  
Aqueous Media ◽  
Environmentally Benign ◽  
Organic Chemical ◽  
Coupling Reactions ◽  
Heck Coupling ◽  
Solvent Free Conditions ◽  
Microwave Reactors ◽  
One Step

Enabling technologies and methodologies were established and combined to afford various environmentally benign processes for laboratory-scale organic synthesis and for the production of fine chemicals, intermediates and pharmaceuticals. The technologies comprised continuous and batch microwave reactors and catalytic membranes. The methodologies included solvent-free conditions, catalysed or uncatalysed processes, the use of aqueous media at high temperature and non-extractive techniques for product isolation. Applications included Hofmann eliminations, Willgerodt and Jacobs–Gould reactions, indole transformations, aldol condensation, Rupe and Meyer–Schuster rearrangements and C–C coupling reactions (including a tandem Heck coupling–dehydrogenation). New processes for catalytic etherification, uncatalysed hydrogen transfer and a one-step arylamidation were also developed. Typical products were N-(4-hydroxyphenyl)acetamide, carvacrol, a-phenylacetamide, cinnamaldehyde, cinnamyl alcohol, acetophenone, indole, 3-hydroxy-1,2-dimethyl-4-pyridone, di(2-phenylethyl) ether, di(cyclopropylmethyl) ether, 3-methylcyclopent-2-enone and a synthetic precursor of nalidixic acid.

scholarly journals Synthesis of β-Amino Carbonyl Compounds via the Iodine-Alumina Catalyzed Three-Component Coupling Reaction under Microwave Irradiation

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Mantu Rajbangshi ◽  
Md. Rumum Rohman ◽  
Icydora Kharkongor ◽  
Hormi Mecadon ◽  
Bekington Myrboh
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Carbonyl Compounds ◽  
Aromatic Amines ◽  
Coupling Reaction ◽  
Environmentally Friendly ◽  
Coupling Reactions ◽  
Reaction Conditions ◽  
Key Features ◽  
Operational Simplicity

Iodine-alumina was employed as a catalyst in the coupling reactions of aldehydes, enolizable ketones, or 1,3-dicarbonyls with methyl carbamate or aromatic amines under microwave irradiation to afford β-amino carbonyl compounds in good-to-excellent yields. The key features of this environmentally friendly methodology are its operational simplicity, mild reaction conditions, and less reaction time.

Room Temperature Suzuki Reactions in Aqueous Media under Air by Palladium(II) Complexes with Pyrazole Derived Ligands

2010 ◽  
Vol 63 (2) ◽  
pp. 315 ◽  
Author(s):  
Kai Xu ◽  
Xin-Qi Hao ◽  
Jun-Fang Gong ◽  
Mao-Ping Song ◽  
Yang-Jie Wu
Keyword(s):  
Aqueous Solution ◽  
13C Nmr ◽  
Room Temperature ◽  
Phenylboronic Acid ◽  
Aqueous Media ◽  
Palladium Complexes ◽  
Coupling Reactions ◽  
X Ray ◽  
Suzuki Reactions ◽  
Aryl Bromides

Two new palladium complexes with pyrazole derived ligands 2a–2b have been easily prepared and well characterized by elemental analysis, 1H NMR, 13C NMR, and IR spectra. Their detailed structures are determined by a single-crystal X-ray analysis of 2a. The two compounds were successfully applied to the Suzuki coupling reactions of aryl bromides with phenylboronic acid, in aqueous solution at room temperature under air, giving the desired coupled products in good to excellent yields with catalyst loadings as low as 0.01–0.05 mol-%.

scholarly journals Efficient pyrazole moiety-containing ligands for Cu-catalyzed O-arylation of phenols

2019 ◽  
Author(s):  
Yingying Zhao ◽  
Xiangyong Wang ◽  
Ryo Kaneyama ◽  
Koichi Kodama ◽  
Takuji Hirose
Keyword(s):  
Steric Hindrance ◽  
Binding Sites ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Catalyst Loading ◽  
Radical Mechanism ◽  
Coupling Reactions ◽  
Electronic Effects ◽  
Electronic Nature ◽  
Imine Nitrogen

Seven N2- and N3-ligands (L1–L7) were developed for the ligand-assisted CuI-catalyzed coupling reactions of aryl halides with phenols. The structural and electronic effects were studied for various combinations of pyridine and/or imine nitrogen binding sites in the ligands. 2-(1-Pyrazolyl)pyridine (L1) featuring two types of binding sites gave the best results, with yields of up to 90% at 100 °C at a catalyst loading of 10 mol% (CuI/L in 1:1 ratio). A non-radical mechanism, proposed for the L1-promoted coupling reaction, well explained the different effects of electronic nature of the substituent and steric hindrance on phenols and aryl halides.

scholarly journals Palladium nanoparticles supported on chitin-based nanomaterials as heterogeneous catalysts for the Heck coupling reaction

2020 ◽  
Vol 16 ◽  
pp. 2477-2483 ◽  
Author(s):  
Tony Jin ◽  
Malickah Hicks ◽  
Davis Kurdyla ◽  
Sabahudin Hrapovic ◽  
Edmond Lam ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Coupling Reaction ◽  
Product Yield ◽  
Pd Nanoparticles ◽  
Coupling Model ◽  
Coupling Reactions ◽  
Heck Coupling ◽  
One Pot ◽  
Cross Coupling Reactions ◽  
Chitin And Chitosan

In this report, chitin and chitosan nanocrystals were used as biomass-based supports for Pd nanoparticles (NPs) used as a heterogeneous catalyst for the Heck coupling reaction. By using a one-pot fabrication method, a Pd salt precursor was directly reduced and deposited onto these nanocrystal catalysts. Characterization of these nanocomposites showed disperse Pd NPs on the surfaces of the chitinous nanocrystals. Heck coupling model reactions revealed full product yield in relatively benign conditions, outcompeting the use of other catalysts supported on biomass-based nanomaterials, including cellulose nanocrystals. These initial results show the potential for using chitinous nanomaterials as effective catalyst supports in cross-coupling reactions.

scholarly journals Facile Synthesis and Characterization of Palladium@Carbon Catalyst for the Suzuki-Miyaura and Mizoroki-Heck Coupling Reactions

2021 ◽  
Vol 11 (11) ◽  
pp. 4822
Author(s):  
Hamed M. Alshammari ◽  
Obaid F. Aldosari ◽  
Mohammad Hayal Alotaibi ◽  
Raja L. Alotaibi ◽  
Mosaed S. Alhumaimess ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
High Catalytic Activity ◽  
Coupling Reactions ◽  
Heck Coupling ◽  
Efficient Catalyst ◽  
X Ray ◽  
Suzuki Reactions

Palladium-based carbon catalysts (Pd/C) can be potentially applied as an efficient catalyst for Suzuki–Miyaura and Mizoroki–Heck coupling reactions. Herein, a variety of catalysts of palladium on activated carbon were prepared by varying the content of ‘Pd’ via an in situ reduction method, using hydrogen as a reducing agent. The as-prepared catalysts (0.5 wt % Pd/C, 1 wt % Pd/C, 2 wt % Pd/C and 3 wt % Pd/C) were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Brunauer–Emmett–Teller (BET) analyses. The catalysts were tested as a coupling catalyst for Suzuki–Miyaura coupling reactions involving aryl halides and phenyl boronic acid. The optimization of the catalyst by varying the palladium content on the activated carbon yielded Pd/C catalysts with very high catalytic activity for Suzuki reactions of aryl halides and a Mizoroki–Heck cross-coupling reaction of 4-bromoanisol and acrylic acid in an aqueous medium. A high ‘Pd’ content and uniform ‘Pd’ impregnation significantly affected the activity of the catalysts. The catalytic activity of 3% Pd/C was found to make it a more efficient catalyst when compared with the other synthesized Pd/C catalysts. Furthermore, the catalyst reusability was also tested for Suzuki reactions by repeatedly performing the same reaction using the recovered catalyst. The 3% Pd/C catalyst displayed better reusability even after several reactions.

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