Showing papers on "Heck reaction published in 2002"
26 Jul 2002
TL;DR: Palladium-CATALYZED Reactions Involving Nucleophilic Attack on -Ligands of Palladium-Alkene, PalladiumAlkyne, and Related Derivatives as mentioned in this paper.
Abstract: PREFACE. CONTRIBUTORS. INTRODUCTION AND BACKGROUND. Historical Background of Organopalladium Chemistry Fundamental Properties of Palladium and Patterns of the Reactions of Palladium and Its Complexes. PALLADIUM COMPOUNDS: STOICHIOMETRIC PREPARATION, IN SITU GENERATION, AND SOME PHYSICAL AND CHEMICAL PROPERTIES. Background for Part II. Pd(0) and Pd(II) Compounds Without Carbon-Palladium Bonds. Organopalladium Compounds Containing Pd(0) and Pd(II). Palladium Complexes Containing Pd(I), Pd(III), or Pd(IV). PALLADIUM-CATALYZED REACTIONS INVOLVING REDUCTIVE ELIMINATION. Background for Part III. Palladium-Catalyzed Carbon-Carbon Cross-Coupling. Palladium-Catalyzed Carbon-Hydrogen and Carbon- Heteroatom Coupling. PALLADIUM-CATALYZED REACTIONS INVOLVING CARBOPALLADATION. Background for Part IV. The Heck Reaction (Alkene Substitution via Carbopalladation- Dehydropalladation) and Related Carbopalladation Reactions. Palladium-Catalyzed Tandem and Cascade Carbopalladation of Alkynes and 1,1-Disubstituted Alkenes. Allylpalladation and Related Reactions of Alkenes, Alkynes, Dienes, and Other -Compounds. Alkynyl Substitution via Alkynylpalladation-Reductive Elimination. Arene Substitution via Addition-Elimination. Carbopalladation of Allenes. Synthesis of Natural Products via Carbopalladation. Cyclopropanation and Other Reactions of Palladium-Carbene (and Carbyne) Complexes. Carbopalladation via Palladacyclopropanes and Palladacyclopropenes. Palladium-Catalyzed Carbozincation. PALLADIUM-CATALYZED REACTIONS INVOLVING NUCLEOPHILIC ATTACK ON LIGANDS. Background for Part V. Palladium-Catalyzed Nucleophilic Substitution Involving Allylpalladium, Propargylpalladium, and Related Derivatives. Palladium-Catalyzed Reactions Involving Nucleophilic Attack on -Ligands of Palladium-Alkene, Palladium-Alkyne, and Related Derivatives. PALLADIUM-CATALYZED CARBONYLATION AND OTHER RELATED REACTIONS INVOLVING MIGRATORY INSERTION. Background for Part VI. Migratory Insertion Reactions of Alkyl-, Aryl-, Alkenyl-, and Alkynylpalladium Derivatives Involving Carbon Monoxide and Related Derivatives. Migratory Insertion Reactions of Allyl, Propargyl, and Allenylpalladium Derivatives Involving Carbon Monoxide and Related Derivatives. Acylpalladation and Related Addition Reactions. Other Reactions of Acylpalladium Derivatives. Synthesis of Natural Products via Palladium-Catalyzed Carbonylation. Palladium-Catalyzed Carbonylative Oxidation. Synthesis of Oligomeric and Polymeric Materials via Palladium-Catalyzed Successive Migratory Insertion of Isonitriles. CATALYTIC HYDROGENATION AND OTHER PALLADIUM-CATALYZED REACTIONS VIA HYDROPALLADATION, METALLOPALLADATION, AND OTHER RELATED SYN ADDITION REACTIONS WITHOUT CARBON-CARBON BOND FORMATION OR CLEAVAGE. Background for Part VII. Palladium-Catalyzed Hydrogenation. Palladium-Catalyzed Isomerization of Alkenes, Alkynes, and Related Compounds without Skeletal Rearrangements. Palladium-Catalyzed Hydrometallation. Metallopalladation. Palladium-Catalyzed Syn-Addition Reactions of X-Pd Bonds (X = Group 15, 16, and 17 Elements). PALLADIUM-CATALYZED OXIDATION REACTIONS THAT HAVE NOT BEEN DISCUSSED IN EARLIER PARTS. Background for Part VIII. Oxidation via Reductive Elimination of Pd(II) and Pd(IV) Complexes. Palladium-Catalyzed or -Promoted Oxidation via 1,2- or 1,4-Elimination. Other Miscellaneous Palladium-Catalyzed or -Promoted Oxidation Reactions. REARRANGEMENT AND OTHER MISCELLANEOUS REACTIONS CATALYZED BY PALLADIUM. Background for Part IX. Rearrangement Reactions Catalyzed by Palladium. TECHNOLOGICAL DEVELOPMENTS IN ORGANOPALLADIUM CHEMISTRY. Aqueous Palladium Catalysis. Palladium Catalysts Immobilized on Polymeric Supports. Organopalladium Reactions in Combinatorial Chemistry. REFERENCES. General Guidelines on References Pertaining to Palladium and Organopalladium Chemistry. Books (Monographs). Reviews and Accounts (as of September 1999). SUBJECT INDEX.
2,193 citations
TL;DR: The Pd-catalyzed cross coupling reactions between sp 2 -C halides and terminal acetylenes have been independently reported by Heck, Cassar and us in 1975 as mentioned in this paper.
1,310 citations
TL;DR: The development of a palladium-catalyzed decarboxylative coupling reaction of arene carboxylates with olefinic substrates is described and reoxidation of the liberated Pd(0) in situ is proposed to establish the catalytic cycle.
Abstract: The development of a palladium-catalyzed decarboxylative coupling reaction of arene carboxylates with olefinic substrates is described. The optimized procedure for decarboxylative palladation employs Pd(O2CCF3)2 as catalyst (0.2 equiv) in the presence of Ag2CO3 (3 equiv) in the solvent 5% DMSO-DMF and proceeds at temperatures of 80−120 °C with a wide range of arene carboxylates and alkenes as substrates. The process is proposed to proceed by an initial Ar-SE reaction involving ipso attack of an electrophilic Pd(II) intermediate on an arene carboxylate to form an arylpalladium(II) species with loss of carbon dioxide. This intermediate is then proposed to react with an olefinic substrate by steps common to the Heck coupling process. Reoxidation of the liberated Pd(0) in situ is proposed to establish the catalytic cycle.
511 citations
TL;DR: In this paper, a summary of palladium-catalyzed cross-coupling reactions, with emphasis on the use of nucleophilic N-heterocyclic carbenes (NHC) as ancillary ligand, is presented.
426 citations
TL;DR: The PdHAP are one of the most active heterogeneous catalysts for both alcohol oxidation under an atmospheric O(2)() pressure and the Heck reaction reported to date and are recyclable in the above organic reactions.
Abstract: Achieving precise control of active species on solid surfaces is one of the most important goals in the development of highly functionalized heterogeneous catalysts. The treatment of hydroxyapatites with PdCl(2)(PhCN)(2) gives two new types of hydroxyapatite-bound Pd complexes. Using the stoichiometric hydroxyapatite, Ca(10)(PO(4))(6)(OH)(2), we found that monomeric PdCl(2) species can be grafted on its surface, which are easily transformed into Pd(0) particles with narrow size distribution in the presence of alcohols. Such metallic Pd species can effectively promote alcohol oxidation using molecular oxygen and are shown to give a remarkably high TON of up to 236 000. Another monomeric Pd(II) phosphate complex can be generated at a Ca-deficient site of the nonstoichiometric hydroxyapatite, Ca(9)(HPO(4))(PO(4))(5)(OH), affording a catalyst with Pd(II) structure and high activity for the Heck and Suzuki reactions. To the best of our knowledge, the PdHAP are one of the most active heterogeneous catalysts for both alcohol oxidation under an atmospheric O(2)() pressure and the Heck reaction reported to date. These Pd catalysts are recyclable in the above organic reactions. Our approach to catalyst preparation based on the control of Ca/P ratios of hydroxyapatites represents a particularly attractive method for the nanoscale design of catalysts.
365 citations
TL;DR: The optimization of the catalyst and reaction conditions allowed Pd/C catalysts with very high activity for Heck reactions of unactivated bromobenzene to be developed and indicate dissolution/reprecipitation of palladium during the reaction.
Abstract: A variety of palladium on activated carbon catalysts differing in Pd dispersion, Pd distribution, Pd oxi- dation state, and water content were tested in Heck reactions of aryl bro- mides with olefins. The optimization of the catalyst (structure ± activity relation- ship) and reaction conditions (temper- ature, solvent, base, and Pd loading) allowed Pd/C catalysts with very high activity for Heck reactions of unactivat- ed bromobenzene (turnover number (TON) 18 000, turnover frequency (TOF) up to 9000, Pd concentrations down to 0.005 mol %) to be developed. High Pd dispersion, low degree of re- duction, sufficient content of water, and uniform Pd impregnation are criteria for the most active system. The catalysts combine high activity and selectivity under ambient conditions (air and mois- ture), easy separation (filtration), and quantitative recovery of palladium. De- termination of Pd in solution after and during the reaction, and catalyst charac- terization before and after the reaction (transmission electron microscopy (TEM), X-ray diffraction (XRD)), indi- cate dissolution/reprecipitation of palla- dium during the reaction. The Pd con- centration in solution is highest at the beginning of the reaction and is a mini- mum ( 1 ppm) at the end of the reac- tion. Palladium leaching correlates sig- nificantly with the reaction parameters.
349 citations
TL;DR: In this paper, the synthesis and X-ray crystallographic characterization of a Pd complex (3) with a rigid C,N,C-tridentate pincer carbene ligand are described.
334 citations
TL;DR: The Pd(OAc)2 or Pd2(dba)3/IMes·HCl (2, IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) system presents very high activity with respect to electron-neutral and electron-rich aryl chlorides.
302 citations
TL;DR: PEG has been used as a solvent medium for regioselective Heck reactions with easy recyclability of solvent and Pd catalyst for the first time.
270 citations
TL;DR: The Heck reaction of aryl chlorides was investigated in the presence of defined monocarbenepalladium(0) complexes to provide the corresponding cinnamic esters and stilbenes in (n)Bu(4)NBr as a ionic liquid in good to excellent yields.
246 citations
TL;DR: In this paper, a straightforward synthesis of ecteinascidin 743 from readily available l-glutamic acid as a single chiral source was accomplished from a simple linear combination of Heck reaction between a diazonium salt and an enamide, oxidative cleavage of the resulting alkene, and intramolecular ortho substitution of the phenol by an aldehyde.
Abstract: A straightforward synthesis of ecteinascidin 743 was accomplished from readily available l-glutamic acid as a single chiral source. Our novel synthesis features a concise and convergent approach for construction of the B-ring, consisting of a sequence involving a stereoselective Heck reaction between a diazonium salt and an enamide, oxidative cleavage of the resulting alkene, and intramolecular ortho substitution of the phenol by an aldehyde.
TL;DR: In this paper, a Pd(OAc)2/diazabutadiene system was developed for the catalytic cross-coupling of aryl halides with arylsboronic acids.
DSM1
TL;DR: In this article, the authors describe their recent efforts in the area of palladium and nickel-catalysed aromatic substitution reactions, and describe the use of a bulky phosphoramidite (13b) as ligand for palladium.
Abstract: In this article we describe our recent efforts in the area of palladium- and nickel-catalysed aromatic substitution reactions. Main focus is on low cost and low waste production methods. The use of aromatic carboxylic anhydrides in the Heck reaction leads to a waste-free protocol. In addition these reactions are easy to work up as no ligands or bases are used. For Heck reactions where substrates or products do not tolerate high temperatures we found that use of a bulky phosphoramidite (13b) as ligand for palladium leads to a very fast reaction at low temperatures. Recycle of palladium in ligand-free Heck and Suzuki reactions is easily accomplished by treating the palladium black that precipitates at the end of the reaction on a carrier material with a small excess of I2 prior to its re-use in the next run. Use of aryl chlorides in the palladium- and nickel-catalysed formation of biaryls can be accomplished by using the nickel-catalysed coupling with arylzinc chlorides. Better still, it was possible to make use of the arylgrignard and use a catalytic amount of ZnCl2. Whereas the strength of these aromatic substitution reactions lies in their broad tolerance of functional groups, one exception was the Sonogashira reaction on 3-bromoaniline. The problem was solved by making use of in situ catalytic protection of the NH2 group with benzaldehyde.
TL;DR: In this paper, a specially optimized air-stable Pd on activated carbon catalyst is demonstrated to be a highly active (TON up to 36,000), selective and convenient heterogeneous catalyst for CC couplings of aryl halides in Heck, Suzuki, and Sonogashira reactions.
Abstract: A specially optimized air-stable Pd on activated carbon catalyst is demonstrated to be a highly active (TON up to 36,000), selective and convenient heterogeneous catalyst for CC couplings of aryl halides in Heck, Suzuki, and Sonogashira reactions. The Pd/ C catalyst developed allows extremely low Pd concentrations (down to 0.0025 mol% for Heck coupling, 0.005 mol% for Suzuki coupling) and high conversions of aryl bromides within a few hours. Easy and complete Pd separation and recovery is possible.
DSM1
TL;DR: In this article, a catalytic cycle based on anionic palladium intermediates is proposed, which results in excellent yields and selectivities, even for the less reactive aryl bromides.
Abstract: Ligand-free palladium can be recovered almost quantitatively from Heck reaction mixtures by filtration after its deposition on a carrier such as silica or celite. Subsequently, it is re-activated to its original activity by adding a small amount of iodine or bromine prior to the next reaction cycle. The catalyst results in excellent yields and selectivities, even for the less reactive aryl bromides. A catalytic cycle based on anionic palladium intermediates is proposed.
TL;DR: In this article, supported palladium catalysts are used for Heck vinylation of iodobenzene with methyl acrylate in N-methylpyrrolidone (NMP) in the presence of triethylamine and sodium carbonate bases.
Abstract: When supported palladium catalysts are used for Heck vinylation of iodobenzene with methyl acrylate in N-methylpyrrolidone (NMP) in the presence of triethylamine and sodium carbonate bases, the reaction proceeds homogeneously with dissolved active palladium species that are formed through coordination of NMP and triethylamine with palladium. These active species easily react with iodobenzene (oxidative addition), beginning the catalytic cycle of Heck coupling. The last step of catalyst regeneration takes place with the action of sodium carbonate. The active palladium species are not stable and deposit the metal to support when they cannot find iodobenzene to react in the reaction mixture after this substrate is completely consumed. The re-deposition of palladium occurs on the surfaces of bare support and/or palladium particles remaining on it, depending on the nature of support surface and the number and size of residual metal particles. The growth of palladium particles has been observed after the reuse of catalyst in some case. However, the supported catalysts are recyclable without loss of activity.
TL;DR: In this article, Heck reactions were performed with 4-bromoacetophenone and n-butyl acrylate, yielding the trans-arylated acrylated ester with high selectivity.
TL;DR: The potentially tridentate ligand 2,6-bis[(methylimidazolium-1-yl)methyl]pyridine dibromide reacts readily with silver(I) oxide in dichloromethane or dimethylsulfoxide to give a dinuclear silver-I-carbene complex that was isolated as the tetrafluoroborate salt as discussed by the authors.
TL;DR: In this article, the palladium leaching during and after Heck reactions of aryl bromides with olefins catalyzed by heterogeneous Pd on activated carbon systems is reported.
Abstract: Parameters that influence the palladium leaching during and after Heck reactions of aryl bromides with olefins catalyzed by heterogeneous Pd on activated carbon systems are reported. Pd leaching correlates significantly with the progress of the reaction, the nature of starting materials and products, solvent, base and atmosphere. The Pd concentration in solution is highest at the beginning of the reaction and is reduced when the reaction is finished. Reaction procedures were developed that allow easy and practicable control and minimization of the Pd leaching at the end of the reaction: Pd re-deposition by: (i) increased temperature, (ii) addition of reducing agents and (iii) working under inert conditions. The Pd concentration in solution after the reaction is reduced to 0.05 ppm Pd (μg Pd/g solution). The catalyst meets all demands for practical application: high activity and selectivity under ambient conditions, complete separation (filtration) of Pd from the product mixture, easy recovery of Pd and commercial availability.
TL;DR: Rate, recycling, and other data suggest that the palladacycles serve as sources of palladium nanoparticles, which are the dominant active catalysts.
TL;DR: Excellent enantioselectivities up to 96% ee are reached for the first time in a Heck reaction with monodentate ligands.
Abstract: An efficient enantioselective intramolecular Heck reaction of cyclohexadienones, using readily available and modular TADDOL-based mono- and bidentate phosphoramidites as chiral ligands and not requiring any additives, has been developed. Excellent enantioselectivities up to 96% ee are reached for the first time in a Heck reaction with monodentate ligands.
TL;DR: In this article, an Oxime-derived, chloro-bridged palladacycles 16 are used for the Heck vinylation of aryl halides, which can be performed under aerobic conditions, with aryls iodides, bromides and chlorides with acrylic esters and olefins displaying turnover numbers (TON) of up to 1010 for phenyl iodide and turnover frequencies (TOF) of 1.4×108 h−1.
Abstract: Oxime-derived, chloro-bridged palladacycles 16 are efficient complexes for the Heck vinylation of aryl halides. The isolated catalysts are thermally stable, not sensitive to air or moisture and easily accessible from inexpensive starting materials. The reaction can be performed under aerobic conditions, with aryl iodides, bromides and chlorides with acrylic esters and olefins displaying turnover numbers (TON) of up to 1010 for phenyl iodide and turnover frequencies (TOF) of 1.4×108 h−1. Deactivated aryl bromides undergo the Heck reaction with styrene with TON and TOF values up to 97,000 and 6063 h−1, respectively. Even aryl chlorides undergo the coupling reaction with olefins with TON up to 920. Complexes 16 catalyze the synthesis of 2,3-disubstituted indenones and indoles in good yields via annulation reaction of internal alkynes with o-bromo- or o-chlorobenzaldehyde and o-iodoaniline, respectively.
TL;DR: A novel 1,4-palladium migration in organopalladium intermediates derived from o-iodobiaryls has been observed under modified Heck reaction conditions.
Abstract: A novel 1,4-palladium migration in organopalladium intermediates derived from o-iodobiaryls has been observed under modified Heck reaction conditions. This migration process can be switched “on” or “off” by simply choosing the appropriate reaction conditions.
TL;DR: The first monocarbenepalladium(0) complexes with benzoquinone and naphthoquinone as additional ligands have been prepared and show a unique coordination mode giving quinone-bridged dimers.
Abstract: The first monocarbenepalladium(0) complexes with benzoquinone and naphthoquinone as additional ligands have been prepared. As demonstrated by NMR spectroscopy and X-ray analysis, the complexes show a unique coordination mode giving quinone-bridged dimers. The monocarbenepalladium(0) complexes allow efficient cross-coupling reactions of aryldiazonium salts with olefins (Heck reaction) and arylboronic acids (Suzuki reaction).
TL;DR: Under the conditions used, crossover is increasingly favored when electron-deficient arenes are involved and products derived from transfer onto the pyridine ring have also been observed.
TL;DR: Catalyst formed from N,N-bis(2,6-diisopropylphenyl)dihydroimidazolium chloride and palladium(II) acetate was used, without added base, to efficiently produce Heck coupled products with olefins and aryl diazonium tetrafluoroborate substrates.
TL;DR: Oxidative addition of oximes to palladium(0) complexes generates alkylideneaminopalladium(II) species, which are utilized as key intermediates for carbon-nitrogen bond formation, and various aza-heterocycles can be synthesized from O-pentafluorobenzoyloximes having an olefinic moiety via an intramolecular Heck-type reaction.
Abstract: Oxidative addition of oximes to palladium(0) complexes generates alkylideneaminopalladium‘II’ species, which are utilized as key intermediates for carbon–nitrogen bond formation. Various aza-heterocycles, such as pyrrole, pyridine, isoquinoline, spiroimine, and azaazulene, can be synthesized from O-pentafluorobenzoyloximes having an olefinic moiety via an intramolecular Heck-type reaction ‘amino-Heck reaction’ by treatment with a catalytic amount of a Pd‘0’ complex. © 2002 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 2: 268–277, 2002: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10030
TL;DR: The complexes efficiently catalyze the Heck olefination of aryl iodides and provide a good yield under phosphine-free conditions and are very sensitive to the nature of the chelating ligand.
TL;DR: The (E )-3,4′,5-trihydroxystilbene (resveratrol) was synthesized via Heck reaction in few steps and with an overall 70% yield as discussed by the authors.