Home About us Contact
|
Home About us Contact | ||
|
|
||
Precatalysts
Kinds of Precatalysts Selected AbstractsSimple Ruthenium Precatalyst for the Synthesis of Stilbene Derivatives and Ring-Closing Metathesis in the Presence of Styrene InitiatorsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2007Cheikh Lo Abstract The ruthenium complex RuCl2(p -cymene)(IMes) was found to be an efficient precatalyst, with styrene as an initiating species, for the alkene metathesis of various styrenes into symmetrical and unsymmetrical stilbene derivatives and for the ring-closing metathesis reaction of a sterically hindered olefin leading to a tetrasubstituted cycloolefin. [source] Ethylene/,-olefin copolymerization with bis(,-enaminoketonato) titanium complexes activated with modified methylaluminoxaneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2005Li-Ming Tang Abstract Copolymerizations of ethylene with ,-olefins (i.e., 1-hexene, 1-octene, allylbenzene, and 4-phenyl-1-butene) using the bis(,-enaminoketonato) titanium complexes [(Ph)NC(R2)CHC(R1)O]2TiCl2 (1a: R1 = CF3, R2 = CH3; 1b: R1 = Ph, R2 = CF3; and 1c: R1 = t -Bu, R2 = CF3), activated with modified methylaluminoxane as a cocatalyst, have been investigated. The catalyst activity, comonomer incorporation, and molecular weight, and molecular weight distribution of the polymers produced can be controlled over a wide range by the variation of the catalyst structure, ,-olefin, and reaction parameters such as the comonomer feed concentration. The substituents R1 and R2 of the ligands affect considerably both the catalyst activity and comonomer incorporation. Precatalyst 1a exhibits high catalytic activity and produces high-molecular-weight copolymers with high ,-olefin insertion. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6323,6330, 2005 [source] ChemInform Abstract: Rational Exploration of N-Heterocyclic Carbene (NHC) Palladacycle Diversity: A Highly Active and Versatile Precatalyst for Suzuki,Miyaura Coupling Reactions of Deactivated Aryl and Alkyl Substrates.CHEMINFORM, Issue 39 2010Guang-Rong Peh Abstract A small library of NHC-palladacycles is prepared by heating readily available palladacycle acetates with imidazolium salts. [source] Simple Ruthenium Precatalyst for the Synthesis of Stilbene Derivatives and Ring-Closing Metathesis in the Presence of Styrene Initiators.CHEMINFORM, Issue 28 2007Cheikh Lo 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] Easily Prepared Air- and Moisture-Stable Pd,NHC (NHC: N-Heterocyclic Carbene) Complexes: A Reliable, User-Friendly, Highly Active Palladium Precatalyst for the Suzuki,Miyaura Reaction.CHEMINFORM, Issue 43 2006Christopher J. O'Brien 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] Combining Enabling Techniques in Organic Synthesis: Solid Phase Assisted Catalysis under Microwave Conditions Using a Stable Pd(II)-Precatalyst.CHEMINFORM, Issue 13 2006Kamal M. Dawood 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] ChemInform Abstract: Ti(NMe2)4 as a Precatalyst for Hydroamination of Alkynes with Primary Amines.CHEMINFORM, Issue 2 2002Yanhui 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] Biaryls Made Easy: PEPPSI and the Kumada,Tamao,Corriu ReactionCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2007Michael G. Organ Prof. Abstract An easily employed, highly versatile Kumada,Tamao,Corriu (KTC) protocol utilizing the PEPPSI (Pyridine, Enhanced, Precatalyst, Preparation, Stabilization and Initiation) precatalysts 1 and 2 is detailed. The ease-of-use of these catalysts and the synthesis of a wide range of hindered biaryls, large coupling partners and drug-like heterocycles, in high yield, makes the PEPPSI-KTC protocol very attractive. The high reactivity of the PEPPSI system allowed a tetra- ortho -substituted heterocycle, 11 to be synthesized at room temperature for the first time using any protocol. The PEPPSI protocols also tolerated the Boc protecting group and phenols required no protection in modified conditions. A relatively large scale (10 g) reaction was also performed with no loss in performance. Furthermore, PEPPSI-IPr, 1, was compared to previously reported highly active phosphine ligands 42, 43, and 44 and was shown to result in significantly better yields under identical conditions. Finally, we demonstrated that the PEPPSI catalyst system is very adept at performing sequential KTC coupling reactions, analogous to multicomponent reactions, which allow complex polyaryl and polyheteroaryl architectures to be produced in one single operation. [source] A Supported Copper Hydroxide as an Efficient, Ligand-free, and Heterogeneous Precatalyst for 1,3-Dipolar Cycloadditions of Organic Azides to Terminal AlkynesCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 1 2009Tatsuyori Katayama Click together: The supported copper hydroxide Cu(OH)x/Al2O3 acts as an efficient heterogeneous precatalyst for the 1,3-dipolar cycloaddition of organic azides to terminal alkynes (click chemistry). The recovered Cu(OH)x/Al2O3 retains its high activity and can be reused. [source] Amino-phosphanes in RhI -Catalyzed Hydroformylation: New Mechanistic Insights Using D2O as Deuterium-Labeling AgentEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2006Jacques Andrieu Abstract In previous work, we have demonstrated that the dangling amino group in amino-phosphane ligands increases the rate of Rh-catalyzed styrene hydroformylation as a function of the amino group basicity and of the distance between the P and N functions. We now report additional stereochemical and mechanistic insights resulting from new catalytic experiments performed with Rh-,-P,N catalytic systems in the presence of D2O. In addition to the expected D0 product, the formation of the ,-D1 aldehyde, PhCH(CH2D)CHO was observed in all cases by 1H and 13C NMR spectroscopy, indicating that H/D exchange occurs for the rhodium-hydride complex. Minor amounts of a ,-D2 product, PhCH(CHD2)CHO, were also formed under certain conditions, demonstrating the reversibility of the olefin coordination step. The composition of the aldehyde mixture is slightly affected by the nature of the catalytic precursor or the P,N ligand used. In the specific case of the ,-P,N ligand [,-P,N = (SAr,SC)-Ph2PCH{o -C6H4Cl(Cr(CO)3)}NHPh], in combination with the [RhCl(COD)]2 precatalyst, products PhCD(CH3)CHO (,-D1) and PhCD(CH2D)CHO (,,,-D2) were also produced. This result suggests a reversible deprotonation assisted by an intramolecular H-bonding interaction between the dangling ammonium function and the carbonyl moiety. This isotopic exchange process decreases the asymmetric induction from 14 to 7,% ee when using the enantiopure version of this ligand. Aldehydes bearing a D atom on the formyl group, e.g. PhCH(CH3)CDO, were never observed. The latter observation excludes protonolysis of the rhodium-acyl intermediate as the aldehyde forming step. In addition, it also excludes a bimolecular reaction involving the rhodium-acyl and rhodium-hydride intermediates.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Iminohydroxamato Early and Late Transition Metal Halide Complexes , New Precatalysts for Aluminoxane-Cocatalyzed Olefin Insertion PolymerizationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2004Alexander Krajete Abstract We report on new families of non-metallocene metal precatalysts for olefin polymerization with titanium, zirconium, vanadium and nickel as the active metal sites. The novel ligand design concept is based on iminohydroxamic acids and their derivatives as the principal chelating units. Various anionic and neutral [N,O] and [N,N] ligand systems are easily accessible by a modular synthetic sequence of imidoyl chlorides with substituted hydroxylamines or hydrazines, respectively. Steric protection of the metal coordination site, a necessary requirement for suppression of chain termination pathways of non-metallocene catalysts, is brought about by bulky aryl substituents on the imino nitrogen atoms. Crystal structures of some of the hydroxamato ligands reveal interesting intermolecular hydrogen-bridged structures, whereas in the solid-state structure of one titanium precatalyst a five-membered chelate was observed, in line with the design principle of these systems. Preliminary ethylene polymerization studies with methylaluminoxane-activated metal complexes (M = Ti, Zr, V, Ni) show that the most active systems are [N,O]NiBr2 catalysts containing neutral O -alkyl iminohydroxamate ligands. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Gold-Catalyzed Cycloisomerization of ,-Aminoallenes to 3-Pyrrolines ,Optimization and Mechanistic Studies,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2006Nobuyoshi Morita Abstract The gold-catalyzed cycloisomerization of various ,-aminoallenes affords the corresponding 3-pyrrolines in good to high chemical yields and , if the amino group is unprotected , with complete axis-to-center chirality transfer. Diminished levels of chirality transfer were observed in cases of N -protected substrates, which may be the result of partial epimerization of the allene in the presence of the gold precatalyst. The low reactivity of the intramolecular hydroamination of unprotected ,-aminoallenes with AuCl3 was improved by use of gold(I) halides as the precatalyst. Mechanistic studies suggest that a gold(I) compound (formed by oxidation of the aminoallene) is the catalytically active species even if the reaction is started with a gold(III) precatalyst. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] N-Heterocyclic Carbene-Mediated Enantioselective Addition of Phenols to Unsymmetrical AlkylarylketenesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Carmen Concellón Abstract Chiral N-heterocyclic carbenes (NHCs) mediate the enantioselective addition of 2-phenylphenol to unsymmetrical alkylarylketenes, delivering ,-alkyl-,-arylacetic acid derivatives with good levels of enantiocontrol (up to 84% ee). Enantiodivergent stereochemical outcomes are observed using 2-phenylphenol and benzhydrol in the NHC-promoted esterification reaction using a triazolium precatalyst derived from pyroglutamic acid, consistent with distinct mechanistic pathways operating within these processes. [source] Ruthenium Catalysts for Controlled Mono- and Bis-Allylation of Active Methylene Compounds with Aliphatic Allylic SubstratesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16 2009Hui-Jun Zhang Abstract The allylation of 1,3-dicarbonyl compounds and malononitrile with aliphatic allylic substrates is achieved under mild conditions in the presence of new ruthenium catalysts. The ruthenium complex [Ru(C5Me5)(2-quinolinecarboxylato)(CH2CHCH- n -Pr)],[BF4] as a precatalyst, allows the synthesis of mono-allylated branched derivatives. On the other hand, the parent complex [Ru(C5Me5)(MeCN)3],[PF6] as a precatalyst, straightforwardly favours the bis-allylation of the procarbonucleophiles leading to bis-allylated bis-linear products. The involvement of the two precatalysts provides a sequential synthesis of unsymmetrical mixed linear-branched bis-allylated derivatives. [source] Organocatalytic Activity of N-Heterocyclic Carbenes in the Michael Addition of 1,3-Dicarbonyl Compounds: Application to a Stereoselective Spirocyclization SequenceADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Thomas Boddaert Abstract An eco-compatible diversity-oriented synthesis of ,-spirolactones and ,-spirolactams is described. The overall transformation involves an olefin cross-metathesis followed by an intramolecular organocatalytic Michael-induced spirocyclization. Under microwave irradiation, the Hoveyda,Grubbs precatalyst can be iteratively used as the source of both the metathesis ruthenium-based catalyst, and the spirocyclization N-heterocyclic carbene catalyst. [source] A Lutidine-Bridged Bis-Perimidinium Salt: Synthesis and Application as a Precursor in Palladium-Catalyzed Cross-Coupling ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009Tao Tu Abstract A novel lutidine-bridged bis-perimidinium dibromide 3 was synthesized in quantitative yield from cheap commercial starting materials. The bisylidene prepared therefrom in situ upon deprotonation is a potent precatalyst in palladium-catalyzed Heck and Suzuki cross-coupling reactions under aerobic conditions, and is efficient even with a ppm scale catalyst loading. Its stronger ,-donor character is held to be responsible for its superior catalytic performance compared with imidazole- and benzimidazole-based analogues bearing the same skeleton precursors. [source] Ruthenium-Indenylidene Complexes: Scope in Cross-Metathesis TransformationsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2008Fabien Boeda Abstract A comparative study examining the catalytic activity of a series of five indenylidene-containing ruthenium complexes in olefin cross-metathesis reactions is presented. Results reveal the greater efficiency of precatalyst 5, highlighting the key role of the N,N, -bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) ligand for this transformation. The scope of this precatalyst was investigated and several microwave experiments were carried out allowing for catalyst loadings as low as 0.1 mol%. Overall, cross-metathesis products were isolated in moderate to excellent yields with high stereoselectivity. [source] From Mono-Triazolium Salt to Bis-Triazolium Salt: Improvement of the Asymmetric Intermolecular Benzoin CondensationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16 2008Yajun Ma Abstract A solution to the long-standing challenge of developing a highly effective method for the enantioselective intermolecular benzoin condensation of aromatic aldehydes is described. The chiral bis-bicyclic triazolium salt , 1,3-bis{(S)-5-benzyl-6,8-dihydro-5H -[1,4]oxazino[2,1- c][1,2,4]triazol-2-ium-2-yl}benzene dichloride [(S)- 5a-1] is currently the most efficient precatalyst for the asymmetric variant of the benzoin condensation. [source] Simple Ruthenium Precatalyst for the Synthesis of Stilbene Derivatives and Ring-Closing Metathesis in the Presence of Styrene InitiatorsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2007Cheikh Lo Abstract The ruthenium complex RuCl2(p -cymene)(IMes) was found to be an efficient precatalyst, with styrene as an initiating species, for the alkene metathesis of various styrenes into symmetrical and unsymmetrical stilbene derivatives and for the ring-closing metathesis reaction of a sterically hindered olefin leading to a tetrasubstituted cycloolefin. [source] 4-Aryl-2-quinolones through a Pseudo-Domino Heck/Buchwald,Hartwig Reaction in a Molten Tetrabutylammonium Acetate/ Tetrabutylammonium Bromide MixtureADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2007Gianfranco Battistuzzi Abstract 4-Aryl-2-quinolones can be prepared from readily available o -bromocinnamamide and aryl iodides using phosphine-free palladium(II) acetate as the precatalyst and a molten tetra(n -butyl)ammonium acetate/tetra(n -butyl)ammonium bromide mixture as the reaction medium. The reaction proceeds through a pseudo-domino process involving two mechanistically independent, sequential catalytic cycles: a Heck reaction followed by an intramolecular Buchwald,Hartwig CN bond forming reaction. [source] Ligand Influence on Metathesis Activity of Ruthenium Carbene Catalysts: A DFT StudyADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2007Bernd Abstract A survey of the concept of active and inactive ligand conformations in ruthenium alkene carbene complexes of the Grubbs catalyst type is presented. This concept is extended to a variety of anionic ligand atoms. Density functional theory calculations at the B3LYP/LACV3P**+//B3LYP/LACVP* level of theory were performed on the precatalyst, 14 valence-electron intermediate, alkene carbene conformers and ruthena(IV)cyclobutane model intermediates for several ligands, such as methoxide, methanethiolate, fluoride, mesylate, water, and ammonia. The rule of the superiority of metathesis catalysts with small and electron-withdrawing halogens does not apply to fluoride ligands. Alkoxides and thiolates also destabilize active carbene conformations, while mesylate ligands lead to a balanced energetic relation of active and inactive carbene orientations. Cationic ruthenium carbene species with aqua or ammine ligands are limited by unfavored ligand dissociation to 14 valence-electron intermediates. A guideline for the design of novel ligand systems for ruthenium carbene complexes as metathesis catalysts is proposed. [source] Yttrium(III)-Catalyzed Intramolecular Alkyne HydroaminationsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2006Hyunseok Kim Abstract The neutral Y(III) complex 4 has been shown to be an effective precatalyst for intramolecular alkyne hydroaminations that provide cyclic amines in good to excellent yields. [source] A Convenient High Activity Catalyst for the Sonogashira Coupling of Aryl BromidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Axel Köllhofer Abstract A mixture of Na2PdCl4, CuI and (t -Bu)3PH+BF4, (molar ratio 4,:,3,:,8) dispersed in H2N(i -Pr)2+Br, can be used as a "single source" precatalyst for the Sonogashira coupling of aryl bromides with various aryl- and alkylacetylenes in HN(i -Pr)2 solvent. Arylacetylenes require just 0.005,mol,% of Pd catalyst at 80,°C, with TOFs ranging between 3,200 and 10,000,h,1. [source] The synthesis and application of 2-acetyl-6-(1-naphthyl)-pyridine oxime as a new ligand for palladium precatalyst in Suzuki coupling reactionJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2009Yongchang Zhou The synthesis of 2-acetyl-6-(1-naphthyl)-pyridine oxime ligand from 2,6-dibromopyridine and 1-bromo-naphthalene is described, and the new palladium(II) complex used as a Pd(0) precatalyst in the Suzuki cross-coupling reaction was studied. The results showed that the novel naphthalene pyridine oxime complex could serve as an efficient precatalyst. J. Heterocyclic Chem., 46, 116 (2009). [source] An environmentally benign room temperature aqueous homo- and copolymerization of styrene and methylmethacrylate catalyzed by [Cp2TiCl2]/NaBPh4JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2009Sudip K. De Abstract [Cp2TiCl2] has been found to be an effective precatalyst for room temperature aqueous homo- and copolymerization of methyl methacrylate and styrene in the presence of a cocatalyst, NaBPh4 and an emulsifier, sodium n -dodecyl sulfate. The polymers obtained are of high molecular weight with low molecular weight distribution. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6496,6503, 2009 [source] Silyl-Terminated Ethylene- co -Norbornene Copolymers by Organotitanium-Based CatalystsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 1 2009Roberto Marconi Abstract Ethylene (E) and norbornene (N) were copolymerized in the presence of PhSiH3 as chain-transfer agent with [Ti(,5:,1 -C5Me4SiMe2NBut)(,1 -Me)2] precatalyst combined with [Ph3C][B(C6F5)4]. The silane was introduced at chain-ends of E- co -N copolymers with concomitant reinitiation of the growing polymer chain. The concentrations of the silane and polymer molecular weight are inversely correlated. The characteristic signals of SiH2Ph chain-ends were observed by 1H NMR. The Si heteroatom is predominantly adjacent to ethylene units in E- co -N copolymers with high N content. [source] Alkyl exchange reaction between dialkylzinc compounds and methylaluminoxane and the effect on propylene polymerizationAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 9 2010Chuanhui Zhang Abstract Alkyl exchange reaction between dialkylzinc compounds and vacuum-dried methylaluminoxane (MAO) was investigated. 1H NMR shows a clear and direct proof of alkyl exchange reaction between ZnEt2 and trimethylaluminum associated with MAO. Detailed analysis of polymers produced in the presence of dialkylzinc compounds gave other indirect but equally strong evidence of alkyl exchange. Therefore, care must be taken to investigate dialkylzinc-based chain transfer reaction in combination with a precatalyst and MAO. Copyright © 2010 John Wiley & Sons, Ltd. [source] One-Pot Synthesis of Bicyclic Fused Cyclopentenone Derivatives from 1-Ethynylcycloalkanols and AldehydesCHEMCATCHEM, Issue 5 2010Victorio Cadierno Dr. Give ,em enough Rupe: A straightforward route to bicyclic fused cyclopentenone derivatives, involving a Rupe rearrangement/aldol condensation/Nazarov cyclization sequence, has been developed starting from readily available 1-ethynylcycloalkanols and aldehydes in the presence of the 16- electron allyl-ruthenium(II) precatalyst [Ru(,3 -2-C3H4Me)(CO)(dppf)][SbF6] and trifluoroacetic acid. [source] Tetraalkylammonium-Free Heck Olefination of Deactivated Chloroarenes by Using a Macrocyclic Catalyst PrecursorCHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2010Christoph Röhlich Dipl.-Chem. Palladium reservoir: A macrocyclic dinuclear Pd complex is applied to the Heck coupling of strongly deactivated aryl chlorides. The complex serves as a very stable precatalyst, which releases active Pd under normal reaction conditions (see scheme). The controlled release and recapture of active Pd provides sufficient stabilization to supersede the addition of tetrabutylammonium bromide. Quantitative conversions can be achieved under additive-free conditions. [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] | |||||||||||||||||||||||||