ADVANCED FUNCTIONAL MATERIALS, Issue 4 2006
H. Yamada
Abstract The silver ionic conductivity in heterogeneous systems of AgBr:Al2O3 and AgI:Al2O3 is highly enhanced by utilizing mesoporous Al2O3 as the insulating phase. The highest Ag+ conductivity of 3.1,×,10,3,,,1,cm,1 (at 25,°C) has been obtained for the AgI:Al2O3 composite with an Al2O3 volume fraction of 0.3. For AgBr:Al2O3, the enhancement of the conductivity is satisfactorily explained in the framework of the ideal space-charge model, while in the case of AgI:Al2O3 stacking disorder is also considered to contribute to the ionic conductivity. [source]

ChemInform Abstract: Cyclopropylmethylation of Benzylic and Allylic Chlorides with Cyclopropylmethylstannane Catalyzed by Gallium or Indium Halide.

CHEMINFORM, Issue 31 2010
Kensuke Kiyokawa
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: Stereoselective Formation of Alkenyl Halides via Magnesium Halide Promoted Ring Opening of Bis-Activated Cyclopropenes.

CHEMINFORM, Issue 23 2009
Yi Wang
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: Pd(II)-Catalyzed Coupling-Cyclization Reaction of o-Ethynylphenylphosphonamides Monoesters with Allyl Halide.

CHEMINFORM, Issue 12 2009
Wei Tang
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]

Chemoselective Mono Halogenation of ,-Keto-sulfones Using Potassium Halide and Hydrogen Peroxide; Synthesis of Halomethyl Sulfones and Dihalomethyl Sulfones.

CHEMINFORM, Issue 19 2007
N. Suryakiran
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]

Direct Halo-Oxygenation of Alkenes with IBX and Potassium Halide.

CHEMINFORM, Issue 28 2005
Zhenliang Pan
No abstract is available for this article. [source]

Incorporation of an Ionic Conducting Alkali-Metal Halide into a Two-Dimensional Copper Oxide Lattice Through a Novel Stepwise Intercalation Route.

CHEMINFORM, Issue 9 2005
Dae Hoon Park
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Zinc Halide Promoted Cyclization of Propargyl Amide Enynes: Novel Six-Membered Ring Formation.

CHEMINFORM, Issue 20 2003
Shoko Yamazaki
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Effect of Halide and Acid Additives on the Direct Synthesis of Hydrogen Peroxide using Supported Gold,Palladium Catalysts

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 6 2009
Edwin Ntainjua N. Dr.
Abstract Acidity is crucial: The effect of halide and acid addition on the direct synthesis of hydrogen peroxide is studied for magnesium oxide- and carbon-supported bimetallic gold,palladium catalysts. When using a Au,Pd/C catalyst, the acidity of the methanol/water solvent has a profound effect on the productivity (P). The effect of halide and acid addition on the direct synthesis of hydrogen peroxide is studied for magnesium oxide- and carbon-supported bimetallic gold,palladium catalysts. The addition of acids decreases the hydrogenation/decomposition of hydrogen peroxide, and the effect is particularly pronounced for the magnesium oxide-supported catalysts whilst for carbon-supported catalysts the pH requires close control to optimize hydrogen peroxide synthesis. The addition of bromide leads to a marked decrease in the hydrogenation/decomposition of hydrogen peroxide with either catalyst. These effects are discussed in terms of the structure of the gold,palladium alloy nanoparticles and the isoelectric point of the support. We conclude that with the highly active carbon-supported gold,palladium catalysts these additives are not required and that therefore this system presents the potential for the direct synthesis of hydrogen peroxide to be operated using green process technology. [source]

Highly Efficient Pd/C-Catalyzed Suzuki Coupling Reaction of p -(un)Substituted Phenyl Halide with (p -Substituted phenyl) Boronic Acid

CHINESE JOURNAL OF CHEMISTRY, Issue 8 2007
Ming-Gang Hu
Abstract A highly efficient Pd/C-catalyzed ligandless, heterogeneous Suzuki reaction of p -(un)substituted phenyl halide with (p -substituted phenyl)boronic acid in DMF/H2O solvent in a short reaction time (0.5 h) at 75 °C was developed. The key for such a catalytic system was the addition of 1 equivalent of tetrabutylammonium bromide. A wide variety of substituents can be tolerated and high yields of cross coupling products were achieved. The palladium catalyst can be easily recovered and reused without significantly decreasing its efficiency. [source]

Effect of Sodium Halide on Dynamic Surface Tension of a Cationic Surfactant

CHINESE JOURNAL OF CHEMISTRY, Issue 8 2005
Lü Feng-Feng
Abstract The equilibrium and dynamic surface tension (DST) of the novel cationic surfactant, 3-(p -nonylphenoxy)-2-hydroxylpropyl trimethyl ammonium bromide, abbreviated as RTAB, were studied. The effect of sodium halide such as NaCl, NaBr and NaI on the DST behavior of the RTAB solution below its CMC was studied in detail. Due to the preferential adsorption, the effect of hydration and salting out, the ability to reduce the DST values at the same concentration was in the order of NaI>NaBr>NaCl. Attributed to its high surface activity, the equilibrium time of the DST of the surfactant solution was insensitive to the ionic strength. [source]

The Polymerization of Tetrahydrofuran Initiated by Niobium(V) and Tantalum(V) Halides

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2008
Fabio Marchetti
Abstract The halides MX5 (M = Nb, Ta, X = F, Cl, Br) (1) are effective in promoting the polymerization of tetrahydrofuran (thf). The polymerization reactions promoted by MCl5 and MBr5 proceed via the ionic species 3, which forms from MX5(thf) (2) by attack of the incoming monomer to the metal-bonded thf. The metal-bonded thf of 3 is not involved in the immediately successive steps of the reaction. The [TaF6], anion is not formed when the polymerization is initiated by TaF5. The activities of the promoters increase according to the series TaBr5 < NbCl5 < TaCl5 < TaF5. The latter possesses high activity and produces high molar mass poly(tetrahydrofuran) (67100 g/mol). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Reusable, Polystyrene-Resin-Supported, Palladium-Catalyzed, Atom-Efficient Cross-Coupling Reaction of Aryl Halides with Triarylbismuths

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2010
Wen-Jun Zhou
Abstract A rapid, atom-efficient, cross-coupling reaction of triarylbismuths with aryl bromides or aryl iodides was reported, and the reaction involves the use of a catalytic amount of polystyrene-supported palladium in the presence of KF as base in DMSO at 105 °C in an open atmosphere. All three aryl groups of the triarylbismuths participated in the reaction and produced polyfunctional biaryls in excellent yields. The polymeric catalyst can be easily separated from the reaction mixture and reused more than 10 times without showing any obvious decrease in activity. [source]

The Use of a Bifunctional Copper Catalyst in the Cross-Coupling Reactions of Aryl and Heteroaryl Halides with Terminal Alkynes

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2008
Minyan Wu
Abstract Copper-catalyzed cross-coupling reactions of aryl halides and heteroaryl halides with terminal alkynes were carried out in DMF at 110,130 °C to provide the corresponding coupling products in satisfactory-to-good yields by using inexpensive 8-hydoxyquinoline as the ligand. Noteworthy is that the bifunctional copper catalyst was successfully applied in this alkynylation reaction for the first time.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Efficient Copper(I)-Catalyzed C,S Cross Coupling of Thiols with Aryl Halides in Water

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2008
Laxmidhar Rout
Abstract CuI efficiently catalyzes the C,S cross coupling of thiols with aryl halides in the presence of tetrabutylammonium bromide in water. The reactions with aryl thiols that have electron-withdrawing and -donating substituents are comparable and afford C,S cross-coupling products in high yield. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

CuI/DABCO-Catalyzed Cross-Coupling Reactions of Aryl Halides with Arylboronic Acids

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2006
Jin-Heng Li
Abstract CuI combined with DABCO (1,4-diaza-bicyclo[2.2.2]octane) was developed as an inexpensive and efficient catalytic system for the Suzuki,Miyaura cross-coupling of aryl halides with arylboronic acids. The couplings between aryl iodides and arylboronic acids catalyzed by catalytic amounts of CuI and DABCO proceeded smoothly in moderate to excellent yields. However, the CuI/DABCO system was less efficient in the reactions of aryl bromides, and a higher reaction temperature was required to improve the yield. For the less activated aryl bromides, a stoichiometric amount of CuI together with TBAB was necessary to obtain satisfactory yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Palladium-Catalyzed Preparation of Propargylic or Allenylic Sulfides from Propargyl Halides or Mesylate and Thiols

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2004
Ken Tsutsumi
Abstract In the presence of a catalytic amount of Pd0 -dppe complex [dppe: 1,2-bis(diphenylphosphanyl)ethane], generated in situ from [Pd2(dba)3·CHCl3] and dppe, propargylic bromide 1a reacted with an equimolar amount of propanethiol at 60 °C in DMF to afford propargylic sulfide 2 in an excellent yield. The reaction occurs readily when carried out in the presence of the weak base triethylamine. The choice of both the phosphane, which is employed as the palladium atom's ligand, and the solvent have a remarkable effect on this reaction. We found that the optimum conditions for the reaction are those using a bidentate phosphane ligand (dppe) in a polar solvent (DMF). Compound 1a reacted smoothly with both aromatic (PhSH) and secondary thiols (CySH) in high yields. The reactions with thiols bearing functional groups (OH or Cl) proceeded selectively in good to moderate yields. Primary chlorides 1b,e were readily converted into their corresponding propargylic sulfides 7,10 in high yields. The Pd0 -dppe catalyst was ineffective in the reaction of the bromide 1g bearing a tBu group at the propargylic position, but the reaction of the corresponding mesylate 1h using the Pd0 -DIOP catalyst [DIOP = O -isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphanyl)butane] at 100 °C afforded the product 11 in good yield. Allenylic sulfides were obtained from 1g,i. We suggest that a cationic ,3 -type complex may be a more reactive intermediate in this catalytic reaction than neutral ,1 - or ,3 -allenyl/propargylpalladium complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Extremely Efficient Cross-Coupling of Benzylic Halides with Aryltitanium Tris(isopropoxide) Catalyzed by Low Loadings of a Simple Palladium(II) Acetate/Tris(p -tolyl)phosphine System

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010
Chi-Ren Chen
Abstract Highly efficient coupling reactions of benzylic bromides or chlorides with aryltitanium tris(isopropoxide) [ArTi(O- i- Pr)3] catalyzed by a simple palladium(II) acetate/tris(p -tolyl)phosphine [Pd(OAc)2/ P(p -tolyl)3] system are reported. The coupling reactions proceed in general at room temperature employing low catalyst loadings of 0.02 to 0.2,mol%, affording coupling products in excellent yields of up to 99%. For benzylic bromides bearing strong electron-withdrawing cyano (CN) or trifluoromethyl (CF3) substituents, the reactions require a higher catalyst loading of 1,mol%, or the reactions are carried out at 60,°C. The catalytic system also tolerates (1-bromoethyl)benzene bearing ,-hydrogen atoms while using a catalyst loading of 1,mol% to afford the coupling product in a 70% yield. [source]

Palladium-Catalyzed Decarboxylative sp - sp2 Cross-Coupling Reactions of Aryl and Vinyl Halides and Triflates with ,,,-Ynoic Acids using Silver Oxide

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009
Hyunseok Kim
Abstract Palladium-catalyzed decarboxylative sp-sp2 cross-coupling reactions of aryl and vinyl halides and triflates with ,,,-ynoic acids using silver oxide have been developed. A variety of ,,,-ynoic acids were readily decarboxylated in the presence of silver oxide and then, generated in situ, silver acetylides were coupled with electrophiles in the presence of a palladium(0) catalyst under neutral conditions, producing either symmetrical or unsymmetrical diarylacetylenes, arylalkylacetylenes and arylvinylacetylenes in good to excellent yields. [source]

Recyclable Heterogeneous Supported Copper-Catalyzed Coupling of Thiols with Aryl Halides: Base-Controlled Differential Arylthiolation of Bromoiodobenzenes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009
Sukalyan Bhadra
Abstract Alumina-supported copper sulfate efficiently catalyzes the S -arylation of aromatic, heteroaromatic and aliphatic thiols with aryl as well as heteroaryl halides under aerobic, ligand-free conditions. This protocol provides an easy access to a variety of thioethers as well as unsymmetrical bis-thioethers by base-controlled differential coupling of thiols with iodo- and bromo-substituents in an aromatic halide. The catalyst is inexpensive, non-air sensitive, environmentally friendly and recyclable. [source]

An Efficient Copper-Catalyzed Amination of Aryl Halides by Aqueous Ammonia

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
Deping Wang
Abstract The copper(I) bromide/1-(5,6,7,8-tetrahydroquinolin-8-yl)-2-methylpropan-1-one (CuBr- L3) combination catalyzed the cross-coupling reactions between aryl or heteroaryl halides and aqueous ammonia with high yields to produce primary aromatic or heteroaromatic amines at room temperature or under mild conditions. [source]

Efficient Cross-Coupling Reactions of Nitrogen Nucleophiles with Aryl Halides in Water

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009
Yong-Chua Teo
No abstract is available for this article. [source]

Efficient Cross-Coupling Reactions of Nitrogen Nucleophiles with Aryl Halides in Water

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2009
Yong-Chua TeoArticle first published online: 17 MAR 200
Abstract A facile and practical strategy has been developed for the N -arylation of nitrogen nucleophiles with aryl halides catalyzed by a combination of iron(III) chloride [FeCl3] and dimethylethylenediamine (dmeda) in water. A variety of nitrogen nucleophiles including pyrazole, indole, 7-azaindole and benzamide afforded the N -arylated products in the presence of the catalytic system (in up to 88% yield). [source]

A Mild and Efficient Iron-Catalyzed Synthesis of Alkenyl Halides via Direct Addition of Benzyl Halides to Arylalkynes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009
Zhongquan Liu
Abstract An efficient and mild iron-catalyzed synthesis of alkenyl halides has been developed via direct carbon-carbon bond formation by using benzyl halides and arylalkynes. [source]

Reduction of Alkyl Halides by Triethylsilane Based on a Cationic Iridium Bis(phosphinite) Pincer Catalyst: Scope, Selectivity and Mechanism

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009
Jian Yang
Abstract A highly efficient procedure for the reduction of a broad range of alkyl halides by triethylsilane based on a cationic iridium bis(phosphinite) pincer catalyst has been discovered and developed. This reduction chemistry is chemoselective and has unique selectivities compared with conventional radical-based processes and the aluminum trichloride/triethylsilane (AlCl3/Et3SiH) and triphenylmethyl tetrakis[pentafluorophenyl]borate/triethylsilane {[Ph3C] [B(C6F5)4]/Et3SiH} systems. Reductions use three equivalents of triethylsilane relative to the halide and can be carried out with very low catalyst loadings and in a solvent-free manner, which may provide an environmentally attractive and safe alternative to many currently practiced methods for reduction of alkyl halides. Mechanistic studies reveal a unique catalytic cycle. The cationic iridium hydride 2,6-bis[di-(tert -butyl)phosphinyloxy)phenyl(hydrido)iridium, (POCOP)IrH+ {POCOP= 2,6-[OP(t- Bu)2]2C6H3} binds and activates the silane. This complex serves as a potent silylating reagent to generate silyl halonium ions, Et3SiXR+, which are reduced by the neutral iridium dihydride to yield alkane product and regenerate the cationic (POCOP)IrH+, thus closing the catalytic cycle. All key intermediates have been identified by in situ NMR monitoring and kinetic studies have been completed. An application of this reduction system to the catalytic hydrodehalogenation of a metal chloride complex is also described. [source]

Copper Nanoparticles on Charcoal for Multicomponent Catalytic Synthesis of 1,2,3-Triazole Derivatives from Benzyl Halides or Alkyl Halides, Terminal Alkynes and Sodium Azide in Water as a "Green" Solvent

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009
Hashem Sharghi
Abstract A one-pot procedure for synthesis of 1,2,3-triazole derivatives via the three-component coupling (TCC) reaction between terminal alkynes, benzyl or alkyl halides, and sodium azide in the presences of 1,mol% nanoparticles copper/carbon (Cu/C) catalyst has been developed. The catalyst showed high catalytic activity and 1,4-regioselectivity for the [3+2],Huisgen cycloaddition in water as a "green" solvent and good to excellent yields were obtained in all cases. This procedure eliminates the need to handle organic azides, and they are generated in situ. The reaction has a broad scope and is especially practical for the synthesis of new azacrown ether and anthraquinone derivatives of triazole. The heterogeneous catalysts were fully characterized by scanning electron microscopy (SEM), atomic forced microscopy (AFM), X-ray diffraction (XRD), inductively coupled plasma (ICP) analysis and FT-IR experimental techniques. The catalyst was recycled ten times without significant loss of activity. [source]

Nickel-Catalyzed Synthesis of Phosphonium Salts from Aryl Halides and Triphenylphosphine

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2008
David Marcoux
Abstract An efficient method to synthesize functionalized tetraarylphosphonium salts is described. The nickel-catalyzed coupling reaction between aryl iodides, bromides, chlorides, or triflates and triphenylphosphine generates tetraarylphosphonium salts in high yields. The coupling is wide in scope and tolerates a variety of functional groups such as alcohols, amides, ketones, aldehydes, phenols, phosphines and amines. [source]

Mechanistic Inferences Derived from Competitive Catalytic Reactions: Pd(binap)-Catalyzed Amination of Aryl Halides

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2008
Antonio
Abstract Healthy competition: The Pd(binap)-catalyzed amination of aryl halides demonstrates how the results from competitive reactions can be strikingly different from those obtained from study of the separate reactions. We show how the competitive network provides mechanistic information not accessible from study of the reactions separately. [source]

Palladium-Catalyzed Intermolecular Three-Component Coupling of Organic Halides with Alkynes and Alkenes: Efficient Synthesis of Oligoene Compounds

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2007
Kana Shibata
Abstract The intermolecular three-component coupling of aryl or vinyl halides, diarylacetylenes, and monosubstituted alkenes effectively proceeds in the presence of palladium acetate, lithium chloride, and sodium bicarbonate as catalyst, promoter, and base, respectively, in aqueous DMF or DMSO to produce the corresponding 1,3-butadiene or 1,3,5-hexatriene derivatives. Use of dienyl bromides allows the coupling to afford 1,3,5,7-octatetraenes. Under the present catalytic conditions, fulvene derivatives are also formed efficiently by the 1:2 coupling of vinyl bromides and diarylacetylenes without adding the alkenes. [source]

Cover Picture: Industrial-Scale Palladium-Catalyzed Coupling of Aryl Halides and Amines ,A Personal Account (Adv. Synth.

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2006
Catal.
Abstract The cover picture shows a typical vessel for industrial scale-up of chemical reactions, in this case for the synthesis of dialkylphosphinobiphenyl ligands. These ligands are important catalyst components for the amination of aryl halides. For more details, see the Review by Stephen L. Buchwald, Christelle Mauger, Gerard Mignani, and Ulrich Scholz on pages 23,,,39. [source]