Home About us Contact
|
Home About us Contact | ||
|
|
||
Palladium Catalyst (palladium + catalyst)
Kinds of Palladium Catalyst Selected AbstractsSynthesis of Polysubstituted Alkenes by Heck Vinylation or Suzuki Cross-Coupling Reactions in the Presence of a Tetraphosphane,Palladium CatalystEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2003Florian Berthiol Abstract Through the use of [PdCl(C3H5)]2/cis,cis,cis -1,2,3,4-tetrakis[(diphenylphosphanyl)methyl]cyclopentane as a catalyst, a range of vinyl bromides undergo Suzuki cross-couplings with arylboronic acids in good yields. Furthermore, the catalyst can be used at low loadings, even for reactions of sterically hindered substrates. Mediated by this catalyst, stilbene and 1,1-diphenylethylene undergo Heck reactions with aryl halides to give triarylethylene derivatives. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] One-Pot Suzuki/Heck Sequence for the Synthesis of (E)-Stilbenes Featuring a Recyclable Silica-Supported Palladium Catalyst via a Multi-Component Reaction in 1,3-PropanediolADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Lionel Joucla Abstract The synthesis of (E)-stilbenes was performed following a one-pot Suzuki/Heck sequence through the use of potassium vinyltrifluoroborate. The combination of heterogeneous palladium/silica (Pd/SiO2) catalyst with potassium phosphate monohydrate (K3PO4,H2O) as base resulted in useful to good isolated yields regardless of the ortho- , meta- or para- substitution of the aryl halides employed. In a sustainable approach, we found that bio-sourced 1,3-propanediol could advantageously replace N -methylpyrrolidone (NMP) as similar yields were obtained. Moreover, the reactivity gap between aryl iodides and bromides resulting from the use of 1,3-propanediol allowed an efficient multi-component approach toward the synthesis of (E)-stilbenes. Furthermore, this heterogeneous catalyst was found to be extremely robust despite the use of aerobic conditions and was successfully re-used over several cycles. [source] Development of Molecular Sieves-Supported Palladium Catalyst and Chemoselective Hydrogenation of Unsaturated Bonds in the Presence of Nitro GroupsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2009Tomohiro Maegawa Abstract The chemoselective hydrogenation of unsaturated bonds and azide functionalities is achieved in the presence of nitro groups by a heterogeneous palladium catalyst supported on molecular sieves (MS3A). The present method shows a wide-range of applicability with regard to substrates and the catalyst can be easily prepared and reused at least three times without any loss of activity. [source] Regioselective C-2 or C-5 Direct Arylation of Pyrroles with Aryl Bromides using a Ligand-Free Palladium CatalystADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Julien Roger Abstract A simple and atom-economical procedure for the regioselective C-2 or C-5 arylation of pyrroles via a CH bond activation is reported. Only 0.5,0.01 mol% of commercially available and air-stable ligand-free palladium(II) acetate [Pd(OAc)2] was employed as the catalyst. The presence of electron-withdrawing substituents such as formyl, acetyl or ester at the C-2 position of the pyrrole is tolerated. This environmentally attractive procedure has also been found to be tolerant to a very wide variety of functional groups on the aryl bromides such as formyl, acetyl, propionyl, ester, nitrile, nitro, fluoro, methoxy, amino or trifluoromethyl. [source] Fluorapatite-Supported Palladium Catalyst for Suzuki and Heck Coupling Reactions of HaloarenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2007M. Lakshmi Kantam Abstract A fluorapatite-supported palladium catalyst (PdFAP) was synthesized by treatment of fluorapatite (prepared by incorporating the basic species fluoride ion into apatite in situ by co-precipitation) with bis(benzonitrile)palladium(II) chloride in acetone. The catalyst displayed high catalytic activity for Suzuki coupling of aryl iodides and bromides with boronic acids at room temperature and chloroarenes at 130,°C in the presence of tetrabutylammonium bromide to give biaryls in excellent yields. Heck olefination of chloroarenes was also successfully carried out by this catalyst. PdFAP was recovered quantitatively by simple filtration and reused with consistent activity. PdFAP was well characterized by XRD, FTIR, XPS, ICP-AES, CO2 TPD and CHN elemental analysis. [source] A Highly Active Heterogeneous Palladium Catalyst for the Suzuki,Miyaura and Ullmann Coupling Reactions of Aryl Chlorides in Aqueous Media,ANGEWANDTE CHEMIE, Issue 24 2010Bizhen Yuan Ein Palladium-Heterogenkatalysator mit dem Metall-organischen Gerüst MIL-101 als Träger vermittelt effiziente Kupplungen in Wasser; so lieferten Suzuki-Miyaura-Kreuzkupplungen und Ullmann-Homokupplungen von substituierten Arylchloriden hohe Ausbeuten. Der Katalysator lässt sich darüber hinaus leicht zurückgewinnen und wiederverwenden (siehe Bild; Cr,blau, O,rot, C,weiß). [source] ChemInform Abstract: Allylic Alkylation of Indoles with Butadiene Promoted by Palladium Catalyst and Triethylborane.CHEMINFORM, Issue 34 2010Masanari Kimura Abstract The combination of Pd(0) catalyst and Et3B effectively activates butadiene (II) to undergo the C-allylation of indoles (I) via oligomerization of the diene (II). [source] ChemInform Abstract: Development of Molecular Sieves-Supported Palladium Catalyst and Chemoselective Hydrogenation of Unsaturated Bonds in the Presence of Nitro Groups.CHEMINFORM, Issue 6 2010Tomohiro Maegawa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Nonsymmetric Pincer-Type Palladium Catalyst in Suzuki, Sonogashira, and Hiyama Couplings in Neat Water.CHEMINFORM, Issue 45 2008Blanca Ines Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] A Novel Palladium Catalyst for the Amination of Electron-Rich Indole Derivatives.CHEMINFORM, Issue 31 2007Nicolle Schwarz Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Highly Active and Selective Palladium Catalyst for Hydroesterification of Styrene and Vinyl Acetate Promoted by Polymeric Sulfonic Acids.CHEMINFORM, Issue 29 2005Hirohito Ooka No abstract is available for this article. [source] Highly Chemoselective Hydrogenation Method Using Novel Finely Dispersed Palladium Catalyst on Silk-Fibroin: Its Preparation and Activity.CHEMINFORM, Issue 27 2005Takashi Ikawa No abstract is available for this article. [source] A Model High Surface Area Alumina-Supported Palladium Catalyst.CHEMINFORM, Issue 19 2005Timothy Lear Abstract For Abstract see ChemInform Abstract in Full Text. [source] The Role of Palladium Catalyst and Base in Stereoselective Transformations of (E)-2-Chlorovinylsulfides.CHEMINFORM, Issue 1 2004Kira Rubina Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Amphiphilic Resin-Supported Palladium Catalyst for High-Throughput Cross-Coupling in Water.CHEMINFORM, Issue 2 2003Yasuhiro Uozumi Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Reactions of 5,5-Dimethyl-4-methylene-1,3-dioxolan-2-one with Amines in the Presence of Palladium Catalyst.CHEMINFORM, Issue 24 2002Min Shi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Facile Synthesis of 2-Arylpropenoic Acid Esters by Cross-Coupling Using Electrogenerated Highly Reactive Zinc and a Palladium Catalyst.CHEMINFORM, Issue 12 2002Aishah A. Jalil Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Novel ZrO2,SO2- 4 Supported Palladium Catalyst for Syntheses of Disubstituted Ureas from Amines by Oxidative Carbonylation.CHEMINFORM, Issue 25 2001Feng Shi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Preparation of 2-Quinolones by Sequential Heck Reduction,Cyclization (HRC) Reactions by Using a Multitask Palladium CatalystCHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2009François-Xavier Felpin Dr. Abstract One-pot sequential Heck reduction,cyclization (HRC) reactions leading to the synthesis of substituted 2-quinolones have been developed by using a heterogeneous or mixed homogeneous/heterogeneous multitask palladium catalyst with charcoal as a support. The whole sequence occurs under very mild conditions without the need for additives (ligand or base) by taking advantage of the high reactivity of aryldiazonium salts as "super electrophiles". Recycling experiments showed that the reused heterogeneous Pd0/C catalyst was not able to promote another HRC sequence but was, however, still highly active for hydrogenation, hydrodehalogenation, as well as hydrogenolysis reactions. [source] Recyclable Heterogeneous Palladium Catalysts in Pure Water: Sustainable Developments in Suzuki, Heck, Sonogashira and Tsuji,Trost ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Marc Lamblin Abstract This review summarizes the progress made essentially these last ten years on heterogeneous palladium catalysis in pure water. The work covers four important palladium-catalyzed transformations for carbon-carbon bond formation: Suzuki, Heck, Sonogashira and Tsuji,Trost reactions. The discussion focuses on the efficiency and reusability of the heterogeneous catalysts as well as on the experimental conditions from a sustainable chemistry point of view. The review is introduced by a discussion on mechanistic aspects inherent to heterogeneous catalysis. [source] Heterogeneous Palladium Catalysts for a New One-Pot Chemical Route in the Synthesis of Fragrances Based on the Heck ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2007Maria Jose Climent Abstract The one-pot synthesis of the fragrance 4-(p -methoxyphenyl)butan-2-one, with raspberry scent, has been carried out using palladium on different supports such as magnesium oxide (MgO), hydrotalcite, hydroxyapatite (HA), aluminium oxide (,-Al2O3) and titanium dioxide (TiO2). The first pathway consists of a Heck coupling between 4-methoxyiodoanisole and methyl vinyl ketone followed by hydrogenation. Palladium supported on titanium dioxide showed the best performance for carrying out both consecutive steps giving 4-(p -methoxyphenyl)butan-2-one with high yields and selectivity. The Pd-TiO2 catalyst is more active than a homogeneous palladium complex that is well accepted in the literature as being highly active for performing Heck reactions. [source] Enantioselective Hydrogenation of N -Acetyldehydroamino Acids over Supported Palladium CatalystsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2007György Szöll Abstract The enantioselective hydrogenation of two N -acetyldehydroamino acids over Cinchona alkaloid-modified, supported palladium catalysts has been studied. Moderate enantioselectivities, up to 36,%, were obtained in the hydrogenation of 2-acetamidocinnamic acid over cinchonidine-modified Pd/TiO2 under low hydrogen pressure. Increase in the pressure or use of benzylamine as additive led to a gradual decrease in the enantiomeric excess and eventually inversion of the sense of the enantioselectivity. On the contrary, the optical purity of the product resulting from the hydrogenation of 2-acetamidoacrylic acid was significantly increased by addition of benzylamine to the reaction mixture. Enantiomeric excess values up to 58,% and 60,% were obtained over Pd/Al2O3 modified by cinchonidine and cinchonine, respectively. These optical purities are the best obtained in the hydrogenation of dehydroamino acid derivatives over chirally modified heterogeneous metal catalysts. [source] ChemInform Abstract: Palladium Catalysts for Dehydrogenation of Ammonia Borane with Preferential B,H Activation.CHEMINFORM, Issue 43 2010Sung-Kwan Kim Abstract [Pd(allyl)]BF4 (I), [Pd(allyl)(2,4-hexadiene)]BF4 (II), and [Pd(MeCN)4](BF4)2 (III) catalyze the dehydrogenation of NH3BH3 most efficiently with a release of 2.0 equiv. [source] ChemInform Abstract: Palladium Catalysts for the Formylation of Vinyl Triflates to Form ,,,-Unsaturated Aldehydes.CHEMINFORM, Issue 44 2008Helfried Neumann Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Highly Practical and General Route for ,-Arylations of Ketones Using Bis-phosphinoferrocene-Based Palladium Catalysts.CHEMINFORM, Issue 40 2008Gabriela A. Grasa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Nafion,Teflon Bimembrane-Supported Palladium Catalysts for Suzuki Coupling Reactions.CHEMINFORM, Issue 16 2008Li Ting Chai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthesis, Reaction, and Recycle of Fluorous Palladium Catalysts for an Asymmetric Allylic Alkylation Without Using Fluorous Solvents.CHEMINFORM, Issue 6 2006Takashi Mino Abstract For Abstract see ChemInform Abstract in Full Text. [source] Efficient Palladium Catalysts for the Amination of Aryl Chlorides: A Comparative Study on the Use of Phosphonium Salts as Precursors to Bulky, Electron-Rich Phosphines.CHEMINFORM, Issue 2 2006Amit Tewari Abstract For Abstract see ChemInform Abstract in Full Text. [source] The Polymer Incarcerated Method for the Preparation of Highly Active Heterogeneous Palladium Catalysts.CHEMINFORM, Issue 29 2003Ryo Akiyama Abstract For Abstract see ChemInform Abstract in Full Text. [source] Heterogeneous Versus Homogeneous Palladium Catalysts for Ligandless Mizoroki,Heck Reactions: A Comparison of Batch/Microwave and Continuous-Flow ProcessingCHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2009Abstract Mizoroki,Heck couplings of aryl iodides and bromides with butyl acrylate were investigated as model systems to perform transition-metal-catalyzed transformations in continuous-flow mode. As a suitable ligandless catalyst system for the Mizoroki,Heck couplings both heterogeneous and homogeneous Pd catalysts (Pd/C and Pd acetate) were considered. In batch mode, full conversion with excellent selectivity for coupling was achieved applying high-temperature microwave conditions with Pd levels as low as 10,3,mol,%. In continuous-flow mode with Pd/C as a catalyst, significant Pd leaching from the heterogeneous catalyst was observed as these Mizoroki,Heck couplings proceed by a homogeneous mechanism involving soluble Pd colloids/nanoparticles. By applying low levels of Pd acetate as homogeneous Pd precatalyst, successful continuous-flow Mizoroki,Heck transformations were performed in a high-temperature/pressure flow reactor. For both aryl iodides and bromides, high isolated product yields of the cinnamic esters were obtained. Mechanistic issues involving the Pd-catalyzed Mizoroki,Heck reactions are discussed. [source] | ||||||||||||||||||||||||||||