Showing papers on "Heck reaction published in 1995"
TL;DR: The Heck reaction has been a topic of fluctuating interest; however, in the last six years activity in this area has flourished as discussed by the authors, leading to impressive sequences consisting of even different reaction types that occur not only in a consecutive mode, but also in a single operation.
Abstract: The palladium-catalyzed coupling of haloarenes and haloalkenes with alkenes, which was discovered by Richard F. Heck in the late sixties, has been a topic of fluctuating interest; however, in the last six years activity in this area has flourished. Careful choice of substrates and skillful tailoring of reaction conditions lead to impressive sequences consisting of even different reaction types that occur not only in a consecutive mode, but also in a single operation. The wellestablished Heck reaction, together with other mechanistically related palladiumcatalyzed transformations with arene, alkene, and alkyne derivatives, opens the door to a tremendous variety of elegant and highly convergent routes to structurally complex molecules. The reaction is not disturbed by heteroatoms such as oxygen and nitrogen (nor by sulfur and phosphorus with some limitations). The spectrum of recent achievements starts with a range of chemoselective and regioselective monocouplings of highly functionalized substrates with unsymmetrical and multisubstituted reaction partners. Other advances include cascade reactions in which three, four, five, and even eight new CC bonds are formed to yield oligofunctional and oligocyclic products with impressive molecular complexity. Even the enantioselective construction of complex natural products with quaternary stereocenters has been achieved with Heck reactions in key steps, as exemplified by the synthesis of crinan, picrotoxinin, and morphine. Today, the Heck reaction is indispensible in the arsenal of synthetic methods available to organic chemists. Certainly it is only a matter of time before the Heck reaction is applied in industrial syntheses.
974 citations
840 citations
249 citations
01 Jan 1995
TL;DR: A discussion of the state of the art and future directions of aqueous organometallic chemistry and catalysis in Debrecen, Hungary can be found in this paper.
Abstract: Preface. NATO Advanced Research Workshop on aqueous organometallic chemistry and catalysis in Debrecen, Hungary L.T. Horvath. The catalytic properties of water soluble phosphine complexes M.T. Beck. Early work on catalysis by water soluble transition metal phosphine complexes F. Joo. Summery of the round table discussion of the state of the art and future directions of aqueous organometallic chemistry and catalysis L.T. Horvath, F. Joo. Transition metal catalyzed reactions of olefins in water: olefin metathesis and isomerization R.H. Grubbs. Aqueous organometallic chemistry: effects of a reactive solvent F. Joo, et al. Aqueous chemistry and catalytic activity of organometallic iridium complexes J.S. Merola, et al. Organometallic radical chemistry in aqueous solution D.R. Tyler. The use of 1,3,5-triaza-7-phosphaadamantane (PTA), a water-soluble, air stable ligand, in organometallic chemistry and catalysis D.J. Darensbourg, et al. Recent developments in metal catalyzed biphasic reactions V. Grushin, A. Alper. Counter phase transfer catalysis by water-soluble phosphine complexes T. Okano. Metal-catalyzed hydrophosphination as a route to water-soluble phosphines P.G. Pringle, et al. Aqueous media in the intramolecular Heck reaction D.B. Grotjahn, X. Zhang. New efficient water-soluble catalysts for two-phase olefin hydroformylation W.A. Herrmann, et al. Rhodium and Palladium water-soluble complexes in the carbonylation reactions. Improvements in the transfer between the organic and aqueous phases F. Monteil, et al. New water soluble phosphines for organometallic chemistry and catalysis in the aqueous phase B.E. Honson, et al. Hexaaquaruthenate(II) as a catalyst precursor in aqueous organometallic catalysis A. C. Beyei. Ruthenium-catalyzedoxidation of chlorinated hydrocarbons in aqueous medium M. Bressan. Hydrosoluble ligands for a new technology E.G. Kuntz. Comparative study of biphase reduction of carbonyl compounds catalyzed by homogeneous and water soluble Ru catalysts S. Sabata, et al. Three approaches to catalytic aqueous organometallic chemistry involving water soluble ligands, some modified cyclodextrins as ligands, and reactions in an aluminophosphate cavity W.R. Jackson, et al. Models for supported aqueous-phase catalysis I. Toth, et al. Stoichiometric and exhaustive hydrolysis of N,N-dialkylcarbamates D. Belli Dell'Amico, et al. Composite hydrogels of the polysaccharide/polyvalent metal type T. Spychaj, et al. Organometallic catalysis in water and in a two-phase system D. Sinou. Chiral sulfonated phosphines in enantioselective catalysis J. Bakos. Asymmetric complex catalysis in micellar systems G. Oehme, et al. Bioorganometallic chemistry: the reaction of a 5-pentamethylcyclopentadienyl)rhodium aqua complex with nucleobases, nucleosides, nucleotides, and oligonucleotides R.H. Fish, et al. On nature's aqueous organometallic and radical chemistry with B12-derivatives B. Krautler. Catalytic hydrogenation of biological membranes: the effects on membrane physical state and functions L. Vigh, F. Joo. Aqueous phospholipid dispersions as vectors for selective homogeneous catalysis P.J. Quinn. Modification of biomembranes by catalytic hydrogenation L. Nadasdi, et al. Subject index.
111 citations
TL;DR: The Heck reaction between aryl halides ArX (X = Br, Cl) and n-butyl acrylate was studied in the presence of catalyst systems containing Pd(OAc)2 and a tertiary phosphine ligand as mentioned in this paper.
Abstract: The Heck reaction between aryl halides ArX (X = Br, Cl) and n-butyl acrylate was studied in the presence of catalyst systems containing Pd(OAc)2 and a tertiary phosphine ligand (PR3, R2P(CH2)PR2). It is shown that all tested arylphosphines except P(o-Tol)3 and P(Mes)3 undergo an extensive PC bond cleavage at temperatures higher than 120°C. As a consequence, vinylic side products are formed with concomitant catalyst deactivation. In the case of triarylphosphines side products originate from reaction intermediates of the type PdII(PAr3)2(Ar)X. These species undergo an aryl-aryl exchange between the palladium center and coordinated phosphine ligands. Subsequent intermolecular phosphine scrambling leads to several isomerized arylpalladium species, all of which couple with n-butyl acrylate to give the corresponding cinnamic ester side products.
95 citations
91 citations
TL;DR: In this article, a mechanism for the Heck arylation on a tetrahedral corner atom is proposed based on the Frontier Molecular Orbitals of this site and the corresponding mechanism established for the homogenously catalyzed reaction.
Abstract: Data have been presented which show that dispersed metals can be considered as viable catalysts for synthetically useful organometallic reactions. In addition, the material used as the catalyst support has been shown to influence the regiochemistry of the reaction. In the Heck arylation an acidic support, such as silica, withdraws electrons from the palladium and this leads to predominant β enol ether formation. Palladium supported on a basic support, such as magnesia, which is electron donating, produces primarily the α product. Electron withdrawal also increases the rate of the reaction. As with a number of other synthetically useful reactions the heterogeneously catalyzed Heck arylation takes place on the coordinately unsaturated corner atoms and adatoms on the metal surface. These single atom active sites are the only ones having a sufficient number of orbitals available for interaction with both the aryl species and the enol ether at the same time, a procedure needed for the reaction to take place. A mechanism for the reaction on a tetrahedral corner atom is proposed. This is based on the Frontier Molecular Orbitals of this site and the corresponding mechanism established for the homogenously catalyzed reaction.
91 citations
TL;DR: In this paper, the palladium promoted vinylation of aryl iodide bound to a solid support was studied under the reaction conditions of water/DMF/Pd(OAc) 2 /PPh 3 /base, the reaction proceeds smoothly and leads to moderate to high yield of product at 37°C after 4-18 hours.
82 citations
TL;DR: A variety of S -thiophenol protecting groups have been evaluated for the Heck reaction as discussed by the authors, and the S -acetyl group appears to be the best suited for facile removal under mild conditions to provide the corresponding free thiols in high yields.
76 citations
TL;DR: The conventional palladium catalysts used in Heck reactions suffer from extensive PC-bond cleavage at temperatures that would be necessary to activate aryl chlorides and electron-rich bromides (> 120°C) as mentioned in this paper.
69 citations
TL;DR: In this article, the Heck reaction was used for the final ring closure step in the construction of a series of macrocyclic compounds, and the Heck reactions were employed for the last ring closure phase of the process.
TL;DR: In this paper, the first pure guanidinium functions were used as active catalysts for aqueous Heck reaction in combination with palladium acetate for the first time.
TL;DR: In this paper, the Heck coupling of 5 with ethylene followed by an NCS mediated oxidative cyclization and elimination sequence was used to synthesize furopyridine 2 in 52% overall yield from 6-hydroxynicotinic acid.
TL;DR: E- and Z-1-alkenyl iodides react with pinacol ester 1 under palladium(0) catalysed, Heck conditions to provide polyenylboronates in moderate yields after purification as discussed by the authors.
TL;DR: In this article, a model of the active surface compound is proposed and confirmed, and strong interaction indicating the existence of chemical bonding was found between the modified silica support and palladium complex.
Abstract: The vinylation of iodobenzene with methyl acrylate was studied using palladium-based heterogeneous catalysts. Methyl cinnamate was formed as vinylation product and benzene as side product. All catalysts were of the type SiO2X-(NH)2-Pd-L2, where L = P(C6H5)3 or C6H5CN and X = Sn, Al or Ti. The catalysts were stable and could be reused several times in normal atmosphere without suffering appreciable loss in catalytic activity. The activity of the catalysts was good even at low temperature, and selectivities were very high. Strong interaction indicating the existence of chemical bonding was found between the modified silica support and palladium complex. A model of the active surface compound is proposed and confirmed.
TL;DR: Aryl triazenes upon treatment with TFA or HBF4 undergo Heck reaction via in-situ generated aryldiazonium salts as mentioned in this paper, where the Heck reaction occurs when the triazene is treated with a TFA/HBF4 mixture.
TL;DR: Aqueous Heck reaction of arenediazonium salts derived from L-Phe and L-Tyr produced styryl amino acids in high yields as discussed by the authors, but the reaction was not considered in this paper.
TL;DR: In this article, two pathways towards the construction of the trikentrin skeleton were presented, one leading to the total synthesis of (±)-cis-Trikentrin A (1).
TL;DR: In this article, the Heck reaction of acrylates was accelerated and partially controlled under high pressure conditions by using a palladium-catalyzed arylation of the acrylate.
TL;DR: Starting from a judiciously substituted N-aminoindole, the Heck reaction led to new classes of heterocyclic compounds: the pyrido[2′,3′-d′]pyridazino[2,3-a]indoles 7 and 8, and pyridioxine[2.3,a]diazepino[1,6,7-h,i]indole 15 as discussed by the authors.
TL;DR: In this article, a catalytic asymmetric synthesis of the key intermediate of (−)-oppositol 4 and (−)-prepinnaterpene 5, brominated terpenes isolated from the marine red algae, has been achieved from cis-hydrindane derivative 2 obtained by an asymmetric Heck reaction.
Abstract: A catalytic asymmetric synthesis of the key intermediate of (−)-oppositol 4 and (−)-prepinnaterpene 5 , brominated terpenes isolated from the marine red algae, has been achieved from cis -hydrindane derivative 2 obtained by an asymmetric Heck reaction.
TL;DR: In this article, the Heck coupling reaction was used to synthesize functional poly(phenylenevinylene) [Ph(NO 2 )-CH=CH-Ph(NR 2 )]-n (R= Hex] n (R = Hex).
Abstract: Functional poly(phenylenevinylene) [Ph(NO 2 )-CH=CH-Ph(NR 2 )-CH=CH] n (R= Hex) has been synthesized using the Heck coupling reaction
TL;DR: In this article, one and two electron processes can be involved in metal catalyzed polycondensations, including the Heck reaction and the Ni-catalyzed synthesis of polyphenylenes.
Abstract: Metal catalyzed polymerizations are chain reactions necessitating a constant valence of the metal. In contrast to that metal catalyzed polycondensations are step growth reactions involving a change of the valence of the metal. Tuning of the reaction by structural variations of the metal catalyst are demonstrated with the Pd-catalyzed vinyl polymerization of norbornene, the alternating copolymerization of ethylene with carbon monoxide and the Heck reaction as examples. One and two electron processes can be involved in metal catalyzed polycondensations. The oxidative polymerization of 2,6-dimethylphenol, the Heck reactions as well the Ni-catalyzed synthesis of polyphenylenes are discussed.