- PROCESSES FOR THE PREPARATION OF ORTHO-ALLYLATED HYDROXY ARYL COMPOUNDS
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The present application describes process for preparing an ortho-allylated hydroxy aryl compounds such as compounds of Formula (I) by reacting an allylic alcohol with a hydroxy aryl compound in the presence of aluminum compound selected from alumina and aluminum alkoxides and in a non-protic solvent wherein at least one carbon atom ortho to the hydroxy group in the hydroxy aryl compound is unsubstituted. The present application also includes compounds of Formula (I).
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- The Employment of Sodium Hydride as a Michael Donor in Palladium-catalyzed Reductions of α, β-Unsaturated Carbonyl Compounds
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Sodium hydride was employed as a Michael donor under the catalysis of PdCl2 for 1,4-conjugate reductions of α, β-unsaturated carbonyl compounds, which features operational simplicity, mild conditions and high atom-economy. The merits of NaH as a reductant were demonstrated by the one-pot or cascade reactions for the syntheses of complex molecules. (Figure presented.).
- Liu, Ye,Mao, Yujian,Hu, Yanwei,Gui, Jingjing,Wang, Liang,Wang, Wei,Zhang, Shilei
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supporting information
p. 1554 - 1558
(2019/02/16)
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- Probing the Evolution of Palladium Species in Pd@MOF Catalysts during the Heck Coupling Reaction: An Operando X-ray Absorption Spectroscopy Study
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The mechanism of the Heck C-C coupling reaction catalyzed by Pd@MOFs has been investigated using operando X-ray absorption spectroscopy (XAS) and powder X-ray diffraction (PXRD) combined with transmission electron microscopy (TEM) analysis and nuclear magnetic resonance (1H NMR) kinetic studies. A custom-made reaction cell was used, allowing operando PXRD and XAS data collection using high-energy synchrotron radiation. By analyzing the XAS data in combination with ex situ studies, the evolution of the palladium species is followed from the as-synthesized to its deactivated form. An adaptive reaction mechanism is proposed. Mononuclear Pd(II) complexes are found to be the dominant active species at the beginning of the reaction, which then gradually transform into Pd nanoclusters with 13-20 Pd atoms on average in later catalytic turnovers. Consumption of available reagent and substrate leads to coordination of Cl- ions to their surfaces, which causes the poisoning of the active sites. By understanding the deactivation process, it was possible to tune the reaction conditions and prolong the lifetime of the catalyst.
- Yuan, Ning,Pascanu, Vlad,Huang, Zhehao,Valiente, Alejandro,Heidenreich, Niclas,Leubner, Sebastian,Inge, A. Ken,Gaar, Jakob,Stock, Norbert,Persson, Ingmar,Martín-Matute, Belén,Zou, Xiaodong
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supporting information
p. 8206 - 8217
(2018/06/22)
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- Iron catalysis for the synthesis of ligands: Exploring the products of hydrophosphination as ligands in cross-coupling
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Catalytic hydrophosphination is a useful technique for the synthesis of phosphines, however, the phosphine products have been little exploited as ligands in catalysis. We have selected three phosphines prepared by iron catalyzed hydrophosphination and used them as ligands in a series of cross-coupling reactions: Heck, Suzuki-Miyaura and Buchwald-Hartwig. Rather than limit the chemistry to simple cross-coupling partners which are almost guaranteed to perform well in these transformations, industrially relevant substrates which are challenging from and electronic and/or steric perspective, along with substrates which contain several heteroatoms, were explored in order to gauge the true potential of these phosphine ligands.
- Espinal-Viguri, Maialen,Mahon, Mary F.,Tyler, Simon N.G.,Webster, Ruth L.
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- Functionalized β-cyclodextrin as supramolecular ligand and their Pd(OAc)2 complex: Highly efficient and reusable catalyst for Mizoroki-Heck cross-coupling reactions in aqueous medium
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A novel class of water soluble palladium complexes with recognition abilities based on functionalized β-cyclodextrin has been synthesized. The complex demonstrated high catalytic activity and a supramolecular platform for phosphine-free Mizoroki-Heck cross-coupling reactions in water. The efficient arylation of alkenes was carried out using different iodo- and bromo-arenes with good to excellent yields (up to 96%). The advantages, like recyclability of catalysts, operational simplicity and accessibility in aqueous medium, make this protocol eco-friendly.
- Dindulkar, Someshwar D.,Jeong, Daham,Kim, Hwanhee,Jung, Seunho
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- Scope and Limitation of the Microwave-Assisted Catalytic Wittig Reaction
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We have developed a microwave-assisted catalytic Wittig reaction. In this paper, we give full account of the scope and limitations of this reaction. A screening of various commercially available phosphine oxides as precatalysts revealed Bu3P=O to be the most promising candidate. We tested 10 silanes for the in situ reduction of the phosphine oxide to generate Bu3P as the actual catalyst. Different epoxides were tested as masked bases. In this context, cyclohexene oxide as well as butylene oxide proved to be suitable. The reaction could be carried out at 125 C, but higher yields and E/Z selectivities were obtained at 150 °C. Under the optimised reaction conditions, more than 40 examples for the conversion of various aldehydes into the corresponding alkenes are reported. The products were obtained in yields of up to 88 with high E selectivities. Moreover, we also describe the further screening of several chiral phosphines as catalysts for the microwave-assisted enantioselective catalytic Wittig reaction. The scope and limitations of the microwave-assisted catalytic Wittig reaction have been evaluated with respect to the catalyst, silane, solvent, reaction conditions, and substrates.
- Hoffmann, Marcel,Deshmukh, Sunetra,Werner, Thomas
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p. 4532 - 4543
(2015/07/27)
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- First Microwave-Assisted Catalytic Wittig Reaction
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We introduce a novel catalytic Wittig reaction based on an inexpensive and readily available phosphane oxide as a precatalyst. The performance of the reaction under microwave irradiation led to significantly improved yields and reaction rates relative to those obtained under conventional heating. Moreover, herein we enclose the first example of the asymmetric catalytic Wittig reaction based on a chiral phosphane as the catalyst.
- Werner, Thomas,Hoffmann, Marcel,Deshmukh, Sunetra
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supporting information
p. 6873 - 6876
(2016/02/19)
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- Multicomponent, flow diazotization/mizoroki-heck coupling protocol: Dispelling myths about working with diazonium salts
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A single pass flow diazotization/Mizoroki-Heck protocol has been developed for the production of cinnimoyl and styryl products. The factors that govern aryl diazonium salt stability have been examined in detail leading to the development of a MeOH/DMF co-solvent system in which the diazonium salts can be generated in the presence of all other reaction components and then coupled selectively to give the desired products. Finally the key role of the reaction quench for flow reactions has been demonstrated.
- Nalivela, Kumara S.,Tilley, Michael,McGuire, Michael A.,Organ, Michael G.
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supporting information
p. 6603 - 6607
(2014/06/09)
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- A robust first-pass protocol for the heck-mizoroki reaction
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The Heck-Mizoroki (HM) reaction is one of the most widely used C-C bond-forming methods of contemporary synthesis. Notwithstanding this, these reactions frequently require significant optimization before efficient transformations can be obtained. We describe here the results of a study that aimed to establish a generic experimental protocol for HM reactions which enables acceptable yields from first-pass experiments. The methodology utilizes readily available stable catalysts and can be applied to a broad range of coupling partners.
- Murray, Paul M.,Bower, John F,Cox, David K,Galbraith, Ewan K,Parker, Jeremy S,Sweeney, Joseph B.
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p. 397 - 405
(2013/04/24)
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- Sustainable heck-matsuda reaction with catalytic amounts of diazonium salts: An experimental and theoretical study
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The palladium-catalyzed Heck-Matsuda reaction with a catalytic amount of an in-situ-generated diazonium salt proceeded under mild and sustainable conditions. The reaction proceeded at room temperature, under base-free conditions, and only generated tBuOH, H2O, and N2 as by-products. Ortho-substituted diazonium salts were more-efficiently coupled to methyl acrylate than their corresponding paraisomers, which required the addition of anisole as an additive. In support of these experimental data, we carried out theoretical studies to gain a deeper understanding of these reaction outcomes.
- Susperregui, Nicolas,Miqueu, Karinne,Sotiropoulos, Jean-Marc,Lecallonnec, Francois,Fouquet, Eric,Felpin, Francois-Xavier
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experimental part
p. 7210 - 7218
(2012/07/27)
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- Tandem reduction + cyclization of ortho-substituted cinnamic esters
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Conjugate reduction of ortho-substituted cinnamic esters by Stryker's reagent to form copper enolates, followed by intramolecular aldol-type cyclization, successfully generated indane and tetralin rings in one pot efficiently. This tandem reaction is generally diastereoselective and provides good yields.
- Sass, Daiane Cristina,De Lucca Jr., Emílio Carlos,Da Silva Barbosa, Jader,De Oliveira, Kleber Thiago,Constantino, Mauricio Gomes
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p. 5371 - 5374
(2011/10/31)
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- Unprecedented substoichiometric use of hazardous aryl diazonium salts in the Heck-Matsuda reaction via a double catalytic cycle
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The first Heck-Matsuda reaction using a catalytic amount of diazonium salts has been discovered. The reaction proceeds through an unprecedented double catalytic cycle in which the electrophile is in situ generated through the reaction advancement. This concept features mild and safe conditions as hazardous aryl diazonium salts are not isolated anymore. Importantly, this sustainable procedure generates only environmentally friendly byproduct such as t-BuOH, H2O, and N2.
- Callonnec, Franccois Le,Fouquet, Eric,Felpin, Franccois-Xavier
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supporting information; experimental part
p. 2646 - 2649
(2011/06/28)
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- Perfluoro-tagged, phosphine-free palladium nanoparticles supported on silica gel: Application to alkynylation of aryl halides, Suzuki-Miyaura cross-coupling, and Heck reactions under aerobic conditions
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The utilization of perfluoro-tagged palladium nanoparticles immobilized on fluorous silica gel through fluorous-fluorous interactions (Pd np-A/FSG) or through covalent bonding to silica gel (Pd np-B) in the alkynylation of aryl halides, in the Suzuki-Miyaura cross-coupling, as well as in the Heck reaction between methyl acrylate and aryl iodides is described. The reactions are carried out under aerobic and phosphine-free conditions with excellent to quantitative product yields in each case. The catalysts are easily recovered and reused several times without significant loss of activity. The alkynylation of aryl halides (under copper-free conditions) and the Suzuki-Miyaura cross-coupling are carried out in water. The Heck reaction of methyl acrylate with aryl iodides is best performed in MeCN. The utilization of Pdnp-B in the synthesis of 2,3-disubstituted indoles from 2-(alkynyl)trifluoroacetanilides and aryl halides is also reported.
- Bernini, Roberta,Cacchi, Sandro,Fabrizi, Giancarlo,Forte, Giovanni,Petrucci, Francesco,Prastaro, Alessandro,Niembro, Sandra,Shafir, Alexandr,Vallribera, Adelina
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supporting information; experimental part
p. 150 - 158
(2010/05/18)
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- Phosphine-free perfluoro-tagged palladium nanoparticles supported on fluorous silica gel: Application to the heck reaction
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The immobilization of phosphine-free perfluoro-tagged palladium nanoparticles Pd-1 on fluorous silica gel (FSG) and their utilization in the Heck reaction have been investigated. High yields of vinylic substitution products have been obtained. Recycling s
- Bernini, Roberta,Cacchi, Sandro,Fabrizio, Giancarlo,Forte, Giovanni,Niembro, Sandra,Petrucci, Francesco,Pleixats, Roser,Prastaro, Alessandro,Sebastian, Rosa Maria,Soler, Roger,Tristany, Mar,Vallribera, Adelina
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p. 561 - 564
(2008/03/28)
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- Highly selective Diels-Alder reactions of directly connected enyne dienophiles
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The paper describes the course of cycloadditions of Diels-Alder dienophiles containing linked enyne sites, each substituted with activating groups. Consistently, it was found that in the enyne cases the Diels-Alder reaction occurred specifically at the ac
- Dai, Mingji,Sarlah, David,Yu, Maolin,Danishefsky, Samuel J.,Jones, Gavin O.,Houk
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p. 645 - 657
(2007/10/03)
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- Templating photodimerization of trans-cinnamic acid esters with a water-soluble Pd nanocage
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A water-soluble octahedral Pd nanocage acting as a reaction vessel templates the photodimerization of substituted trans-cinnamic acid methyl esters in water. Irradiation of the host-guest complexes of trans-cinnamic acid methyl esters with the Pd nanocage resulted in selective formation of a syn head-head dimer in addition to the corresponding cis isomer. These results suggest that the guest molecules are preoriented in a selective fashion with the hydrophilic ester group facing water and the hydrophobic aryl group tucked within the cavity of the host. Such an orientation occurs at the hydrophobic-hydrophilic interface between the nanocage exterior and interior. Weak intermolecular C-H-π and π-π interactions between the host and the guest(s) are likely to be responsible for the lack of mobility of the reactant olefins during their short excited-state lifetime.
- Karthikeyan,Ramamurthy
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p. 452 - 458
(2007/10/03)
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- Heck reactions of ortho-substituted arenediazonium salts: Critical observations on electronic effects
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An attempted Heck reaction of o-diethylamido phenyldiazonium tetrafluoroborate follows a unique radical-chain protodediazoniation pathway that is triggered by a facile 1,5-[H] shift of the derived aryl radical. Other ortho-substituted salts, irrespective of their redox potentials and structure, behave in the normal way.
- Sengupta, Saumitra,Bhattacharyya, Sanchita
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p. 2035 - 2037
(2007/10/03)
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- Synthesis and biological activity of cinnamaldehydes as angiogenesis inhibitors
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A series of 2-hydroxycinnamaldehyde derivatives was synthesized for examing a structure-activity relationship for inhibition of angiogenesis. The anti-angiogenic effects of 2'-substituted cinnamaldehydes and related analogs were determined in a chick embryo chorioallantoic membrane assay system.
- Kwon, Byoung-Mog,Lee, Seung-Ho,Cho, Young-Kwon,Bok, Song-Hae,So, Seung-Ho,Youn, Mi-Ran,Chang, Soo-Ik
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p. 2473 - 2476
(2007/10/03)
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- Palladium complexes supported on hybrid organic-inorganic zirconium phosphite: Selectivity in the Heck reaction
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Supported palladium complex on zirconium phosphite-phosphonate was made from triphenylphosphine phosphonic acid. The supported catalyst showed significant selectivity in the competitive Heck reaction between iodobenzene and different iodobenzoates. The re
- Villemin, Didier,Jaffres, Paul-Alain,Nechab, Belkacem,Courivaud, Frederic
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p. 6581 - 6584
(2007/10/03)
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- Formation of Lactones in the Heck Reaction
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The Heck reaction of methyl 2-bromobenzoate with methyl acrylate gave a mixture of alkene 1 and lactone 9.Acrylonitrile and methyl 2-bromobenzoate gave lactone 10.Ethyl 2-bromobenzoate and methyl acrylate or acrylonitrile gave the alkenes 2 and 4 respecti
- Parker, Julie A.,Stanforth, Stephen P.
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p. 1587 - 1588
(2007/10/03)
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- Synthesis of 6-(3-Aryl-2-propenyl)-2,3-dihydro-5-hydroxybenzofuran Derivatives by Cross Coupling Reactions
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The synthesis of 6-(3-aryl-2-propenyl)-2,3-dihydro-5-hydroxybenzofuran derivatives by cross coupling between 6-bromo-2,3-dihydrobenzofurans and cinnamyl halides via organo-metallic compounds has been explored.Palladium catalysed reaction between benzofury
- Alabaster, Ramon J.,Cottrell, Ian F.,Hands, David,Humphrey, Guy R.,Kennedy, Derek J.,et al.
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p. 598 - 603
(2007/10/02)
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