Chemistry - A European Journal

Cover image for Vol. 16 Issue 5

February 1, 2010

Volume 16, Issue 5

Pages 1403–1709

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
    8. Full Papers
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    1. Cover Picture: Reactive Intermediates: A Transient Electrophilic Phosphinidene Caught in the Act (Chem. Eur. J. 5/2010) (page 1403)

      Helen Jansen, Michiel C. Samuels, Erik P. A. Couzijn, J. Chris Slootweg, Andreas W. Ehlers, Peter Chen and Koop Lammertsma

      Version of Record online: 26 JAN 2010 | DOI: 10.1002/chem.201090013

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      Phosphinidene complex [Me3NC6H4[BOND]P[DOUBLE BOND]W(CO)5]+ was observed by tandem mass spectrometry and its identity was confirmed by the addition to alkenes in the instrument's ion guide that is shown in the background of the cover picture. The gas-phase experiments are consistent with solution-phase and computational studies as reported by K. Lammertsma, P. Chen et al. in their Communication on page 1454 ff.

  2. Graphical Abstract

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    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
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  3. Corrigendum

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    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
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    1. You have free access to this content
      Striking AcOH Acceleration in Direct Intramolecular Allylic Amination Reactions (page 1414)

      Fady Nahra, Frédéric Liron, Guillaume Prestat, Carlo Mealli, Abdelatif Messaoudi and Giovanni Poli

      Version of Record online: 26 JAN 2010 | DOI: 10.1002/chem.201090015

      This article corrects:

      Striking AcOH Acceleration in Direct Intramolecular Allylic Amination Reactions

      Vol. 15, Issue 42, 11078–11082, Version of Record online: 30 SEP 2009

  4. News

    1. Top of page
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    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
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  5. Concept

    1. Top of page
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    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
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    1. Singularity Model

      A Singularity Model for Chemical Reactivity (pages 1420–1427)

      Fredric M. Menger and Rafik Karaman

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902683

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      An absolute catastrophe! A singularity (or catastrophe) is defined classically as an abrupt change resulting from a smooth increase or decrease in external conditions. This article proposes a model for chemical reactivity that involves singularities in the timing of bond-making and bond-breaking events. Experimental observations are provided to support the singularity effect.

  6. Communications

    1. Top of page
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    4. Corrigendum
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    1. Drug Delivery

      Evidence for Drug Release from a Metalla-Cage Delivery Vector Following Cellular Internalisation (pages 1428–1431)

      Olivier Zava, Johan Mattsson, Bruno Therrien and Paul J. Dyson

      Version of Record online: 23 DEC 2009 | DOI: 10.1002/chem.200903216

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      A new journey in the Trojan horse odyssey: Encapsulation of a fluorescent guest in the hydrophobic cavity of a cationic metalla-prismatic cage shows that the guest is released following cellular uptake, which illustrates the potential of this kind of water-soluble metalla-cage to act as drug carrier.

    2. Synthesis Design

      An Expeditious Route to 1α,25-Dihydroxyvitamin D3 and Its Analogues by an Aqueous Tandem Palladium-Catalyzed A-Ring Closure and Suzuki Coupling to the C/D Unit (pages 1432–1435)

      Pranjal Gogoi, Rita Sigüeiro, Silvina Eduardo and Antonio Mouriño

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902972

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      Daily vitamins: A mild, general, and highly stereoselective Pd0-catalyzed cascade to the triene system of the hormone 1α,25-dihydroxyvitamin D3 and six representative analogues is reported. The intramolecular cyclization of an enol–triflate (lower fragment) followed in situ by Suzuki–Miyaura coupling with an alkenyl boronic ester (upper fragment, also efficiently prepared by Pd0-catalyzed coupling) in equimolar amounts under protic conditions is ideal for the preparation of small amounts of new vitamin D analogues for biological testing (see scheme).

    3. C[BOND]H Activation

      One-Pot Synthesis of Diarylmethylidenefluorenes and Phenanthrenes by Palladium-Catalyzed Multiple C[BOND]H Bond Functionalization (pages 1436–1440)

      Vedhagiri S. Thirunavukkarasu, Kanniyappan Parthasarathy and Chien-Hong Cheng

      Version of Record online: 29 DEC 2009 | DOI: 10.1002/chem.200902726

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      A palladium-catalyzed rapid synthesis of diarylmethylidenefluorenes and phenanthrenes by multiple C[BOND]H bond activation, C[BOND]C bond formation, and Heck-type cyclization is described (see scheme).

    4. Porous Membranes

      A pH-Responsive Gate Fabricated with Nanochannels and Nanoparticles (pages 1441–1444)

      Xiaoli Zhu, Yuexing Liu, Junyi Huang and Genxi Li

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902783

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      Open for business! A novel pH-responsive gate has been constructed of nanochannels, nanoparticles, and amphoteric compounds to form a complete gate (see figure; PAAOM=porous anodic aluminum oxide membrane). The advantage of this system is that more readily available and tunable compounds than smart polymers have been used.

    5. Stereoselective Reactions

      A Convergent General Strategy for the Functionalized 2-Aryl Cycloalkyl-Fused Chromans: Intramolecular Hetero-Diels–Alder Reactions of ortho-Quinone Methides (pages 1445–1448)

      Jumreang Tummatorn, Somsak Ruchirawat and Poonsakdi Ploypradith

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902403

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      Five and six: 3,4-Cyclopentyl- and cyclohexyl-fused 2-arylchromans could be readily prepared from the intramolecular hetero-Diels–Alder reactions of the corresponding ortho-quinone methide (o-QM) precursors tethered to the styrenes under mild reaction conditions. The products were obtained with good to excellent diastereoselectivity (up to>99:1 dr; see scheme; MOM=methoxymethyl).

    6. Vibrational Signature of Double-End-Linked Molecules at Au Nanojunctions Probed by Surface-Enhanced Raman Spectroscopy (pages 1449–1453)

      Yi-Fan Huang, Nai-Ning Yin, Xiang Wang, De-Yin Wu, Bin Ren and Zhong-Qun Tian

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902199

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      Up the junction! Au/molecule/Au junctions were obtained by spreading Au NPs over an Au substrate pre-adsorbed with molecules with a bifunctional group. Molecules binding to the surface with the heterocyclic aromatic molecules show signature a band after the formation of molecular junctions, as revealed by SERS and quantum chemical calculations.

    7. Phosphinidene Complexes

      Reactive Intermediates: A Transient Electrophilic Phosphinidene Caught in the Act (pages 1454–1458)

      Helen Jansen, Michiel C. Samuels, Erik P. A. Couzijn, J. Chris Slootweg, Andreas W. Ehlers, Peter Chen and Koop Lammertsma

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902715

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      Trapped! Transient electrophilic phosphinidenes [R[BOND]P[DOUBLE BOND]W(CO)5] have emerged as versatile intermediates that are highly valuable in the synthesis of a plethora of organophosphorus compounds, nevertheless their existence has never been unequivocally established. By employing electrospray ionisation tandem mass spectrometry (ESI-MS/MS), this low-valent species has now been detected and its gas-phase reactivity perfectly matches the well-established solution-phase data.

    8. Nanoparticles

      Size-Tunable Synthesis of Monodisperse Water-Soluble Gold Nanoparticles with High X-ray Attenuation (pages 1459–1463)

      Zhijiang Wang, Lina Wu and Wei Cai

      Version of Record online: 23 DEC 2009 | DOI: 10.1002/chem.200902463

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      Cluster control: Highly stable, monodisperse, water-soluble gold nanoparticles with high X-ray attenuation have been prepared by controlling the reaction kinetics for the formation and growth of the gold nuclei by a green single-phase method (see figure). The process developed can produce high-quality gold nanoparticles in controlled sizes without going through a laborious size-sorting procedure.

  7. Full Papers

    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
    8. Full Papers
    9. Preview
    1. Cluster Compounds

      Structure-Directing Forces in Intercluster Compounds of Cationic [Ag14(C[TRIPLE BOND]CtBu)12Cl]+ Building Blocks and Polyoxometalates: Long-Range versus Short-Range Bonding Interactions (pages 1464–1469)

      Franziska Gruber, Martin Schulz-Dobrick and Martin Jansen

      Version of Record online: 7 JAN 2010 | DOI: 10.1002/chem.200902538

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      Power of the force: Opposite to the expectation that structures of intercluster compounds, consisting of charged, nanometer-sized building blocks, were primarily determined by long-range Coulomb interactions (an example is shown here), the topologies found experimentally are rather indicative for various types of short-range bonding to dominate, even allowing direct contact among equally charged nanounits.

    2. Oligoynes

      Efficient Intramolecular Charge Transfer in Oligoyne-Linked Donor–π–Acceptor Molecules (pages 1470–1479)

      Lars-Olof Pålsson, Changsheng Wang, Andrei S. Batsanov, Simon M. King, Andrew Beeby, Andrew P. Monkman and Martin R. Bryce

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902099

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      Conjugation makes the difference: The synthesis of a series of triphenylamine–(C[TRIPLE BOND]C)n–2,5-diphenyl-1,3,4-oxadiazole dyad molecules (see picture) and a related triphenylamine–C6H4–(C[TRIPLE BOND]C)3–oxadiazole dyad is reported. Cyclic voltammetric and photophysical studies of these compounds reveal new insights into conjugative effects in oligoyne molecular wires.

    3. Anion Sensing

      Colourimetric Carboxylate Anion Sensors Derived from Viologen-Based Receptors (pages 1480–1492)

      Adam N. Swinburne, Martin J. Paterson, Kathrin H. Fischer, Sara Jane Dickson, Emma V. B. Wallace, Warwick J. Belcher, Andrew Beeby and Jonathan W. Steed

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902609

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      Purple patch! Tri- and tetrapodal viologen-based anion receptors showing a colourimetric response to carboxylates, such as acetate, have been synthesised. Alteration of the anion binding sites allows for binding-site competition within a receptor, resulting in a delayed colourimetric response that is dependent on the binding arms. DFT calculations and experimental measurements allow the colour change to be assigned to an anion–receptor charge-transfer process (see scheme).

    4. Ionic Liquids

      Amino Acid Based Low-Molecular-Weight Ionogels as Efficient Dye-Adsorbing Agents and Templates for the Synthesis of TiO2 Nanoparticles (pages 1493–1505)

      Sounak Dutta, Dibyendu Das, Antara Dasgupta and Prasanta Kumar Das

      Version of Record online: 17 DEC 2009 | DOI: 10.1002/chem.200901917

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      Such a versatile medium: Ionic liquids are immobilized with amino acid based low-molecular-weight gelators. A logical structure–property correlation is shown between the probable factors of ionogelation by using various spectroscopic and microscopic studies. The self-assembled supramolecular ionogels are used as a template for the synthesis of small-sized TiO2 nanoparticles (see picture). A representative ionogel was also used for water purification because these gels show efficient dye-adsorption abilities.

    5. Reactive Intermediates

      Intermediates Involved in the Oxidation of Nitrogen Monoxide: Photochemistry of the cis-N2O2⋅O2 complex and of sym-N2O4 in Solid Ne Matrices (pages 1506–1520)

      Helmut Beckers, Xiaoqing Zeng and Helge Willner

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902406

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      Triple change: IR irradiation is shown to induce a rearrangement of the cis-N2O2⋅O2 complex isolated in a Ne matrix to form a weakly bound (NO2)2 radical pair, which further isomerises to trans-ONONO2 and sym-N2O4 (D2h) (see figure).

    6. Reaction Mechanisms

      Pincer-Type Heck Catalysts and Mechanisms Based on PdIV Intermediates: A Computational Study (pages 1521–1531)

      Olivier Blacque and Christian M. Frech

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902091

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      Controversial PdII/PdIVcycles often have been proposed in Heck reactions promoted by pincer complexes as alternatives to the formation of palladium nanoparticles. Computational studies on experimentally used aminophosphine-, phosphine-, and phosphite-based pincer-type Heck catalysts demonstrate that PdII/PdIV mechanisms (see scheme) are indeed thermally accessible and hence are a true alternative to palladium nanoparticle formation. Consequently, pincer-type PdIV complexes should be considered as intermediates in polar, nonprotic solvents in reactions with aryl halides performed at elevated temperatures.

    7. Metal-Ion Recognition

      Selective Metal-Cation Recognition by [2.2]Ferrocenophanes: The Cases of Zinc- and Lithium-Sensing (pages 1532–1542)

      Francisco Otón, Imma Ratera, Arturo Espinosa, Klaus Wurtz, Teodor Parella, Alberto Tárraga, Jaume Veciana and Pedro Molina

      Version of Record online: 9 DEC 2009 | DOI: 10.1002/chem.200901421

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      Selective metal-ion recognition: In the same way as a geostationary satellite is fixed in a planetary orbit, a Li+ ion is selectively trapped in the planetary orbit of a ferrocene with the help of the attractive field of the two nitrogen atoms of the iminophosphorane bridges of a structurally rigid [2.2]ferrocenophane (see figure). The rigid architecture of multinuclear [2.2]ferrocenophane also permits, in another receptor, the selective binding of Zn2+ in the presence of Cd2+.

    8. Boronated Protoporphyrins

      Boron-Containing Protoporphyrin IX Derivatives and Their Modification for Boron Neutron Capture Therapy: Synthesis, Characterization, and Comparative In Vitro Toxicity Evaluation (pages 1543–1552)

      Mohamed E. El-Zaria, Hyun Seung Ban and Hiroyuki Nakamura

      Version of Record online: 17 DEC 2009 | DOI: 10.1002/chem.200901532

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      Prodrugs: A new series of natural boronated protoporphyrins with systematically varied properties was prepared. The differences in the natures of the covalent bonds between the porphyrin and the borate anion components, as well as in the lengths of the alkoxy chain linkages to the former vinyl groups of protoporphyrin IX resulted in molecules that exhibited a wide spectrum of water solubility.

    9. Metal–Organic Frameworks

      Reversible Interconversion between Luminescent Isomeric Metal–Organic Frameworks of [Cu4I4(DABCO)2] (DABCO=1,4-Diazabicyclo[2.2.2]octane) (pages 1553–1559)

      Dario Braga, Lucia Maini, Paolo P. Mazzeo and Barbara Ventura

      Version of Record online: 9 DEC 2009 | DOI: 10.1002/chem.200900743

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      Switch your MOF: Metal–organic frameworks (MOF) of cluster [Cu4I4(DABCO)2] have been prepared and characterized as two different crystalline forms, I and II. MOF I converts into II on exposure to acetonitrile or methanol vapour, whereas II reverts to I when heated in a closed pan at 250 °C (see figure). Both isomers exhibit luminescence properties in the solid state and these have been characterized at room temperature and at 77 K.

    10. Zeolite Analogues

      Adsorption of CO2, CH4, and N2 on Zeolitic Imidazolate Frameworks: Experiments and Simulations (pages 1560–1571)

      Javier Pérez-Pellitero, Hedi Amrouche, Flor R. Siperstein, Gerhard Pirngruber, Carlos Nieto-Draghi, Gérald Chaplais, Angélique Simon-Masseron, Delphine Bazer-Bachi, David Peralta and Nicolas Bats

      Version of Record online: 8 DEC 2009 | DOI: 10.1002/chem.200902144

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      Successful simulation: A newly developed intermolecular force field can accurately reproduce the measured gas-adsorption isotherms on two zeolitic imidazolate frameworks. The simulation results can be used to identify preferential adsorption sites, which can be correlated with various parameters by topological mapping of electrostatic potential-energy surfaces (see figure).

    11. Ionic Liquids

      Ionic Liquids Based on Azolate Anions (pages 1572–1584)

      Marcin Smiglak, C. Corey Hines, Timothy B. Wilson, Shailendra Singh, Adam S. Vincek, Kostyantyn Kirichenko, Alan R. Katritzky and Robin D. Rogers

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200901418

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      Energetic ionic liquids: We present work the on synthesis and characterization of new energetic organic salts with an emphasis on organic azolate anions. Thirty one salts were synthesized (such as depicted) by pairing diverse cations with azolate energetically substituted anions. The azolates in general are surprisingly stable in the systems explored and ionic liquid behavior was observed with all combinations of the 1-butyl-3-methylimidazolium cation and the heterocyclic azolate anions studied.

    12. Organocatalysis

      Dynamic Kinetic Asymmetric Transformation (DYKAT) by Combined Amine- and Transition-Metal-Catalyzed Enantioselective Cycloisomerization (pages 1585–1591)

      Gui-Ling Zhao, Farman Ullah, Luca Deiana, Shuangzheng Lin, Qiong Zhang, Junliang Sun, Ismail Ibrahem, Pawel Dziedzic and Armando Córdova

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902818

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      Dual catalysis: A one-pot combination of asymmetric amine organocatalysis and transition-metal catalysis allowed dynamic kinetic asymmetric transformations (DYKATs) with α,β-unsaturated aldehydes and propargylated carbon acids, affording functionalized cyclopentenes with up to 99 % ee (see graphic). This system also proved useful for the generation of all-carbon quaternary stereocenters.

    13. Cycloaddition

      The Sequential Building of Chiral Macrocyclic Bis-β-Lactams by Double Staudinger–Cu-Catalyzed Azide–Alkyne Cycloadditions (pages 1592–1600)

      Daniel Pellico, Mar Gómez-Gallego, Pedro Ramírez-López, María José Mancheño, Miguel A. Sierra and M. Rosario Torres

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902685

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      Copper-catalyzed cycloaddition: A novel approach for the synthesis of macrocyclic bis-β-lactams based on the Cu-catalyzed alkyne–azide cycloaddition (CuAAC) is reported (see graphic). The procedure is general and allows access to a full range of diastereomerically or enantiomerically pure macrocyclic cavities in good yields.

    14. Supramolecular Chemistry

      Self-Assembly of Ureido-Pyrimidinone Dimers into One-Dimensional Stacks by Lateral Hydrogen Bonding (pages 1601–1612)

      Marko M. L. Nieuwenhuizen, Tom F. A. de Greef, Rob L. J. van der Bruggen, Jos M. J. Paulusse, Wilco P. J. Appel, Maarten M. J. Smulders, Rint P. Sijbesma and E. W. Meijer

      Version of Record online: 28 DEC 2009 | DOI: 10.1002/chem.200902107

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      An isodesmic pathway is followed in the self-assembly of ureido-pyrimidinone (UPy) dimers substituted with an additional urea functionality into one-dimensional stacks through lateral non-covalent interactions (see scheme) in various solvents. In CDCl3, NMR studies show the formation of short stacks, whereas temperature-dependent CD studies on chiral UPy dimers in heptane show the formation of larger helical stacks.

    15. Cluster Compounds

      The Role of Solvent on the Mechanism of Proton Transfer to Hydride Complexes: The Case of the [W3PdS4H3(dmpe)3(CO)]+ Cubane Cluster (pages 1613–1623)

      Andrés G. Algarra, Manuel G. Basallote, Marta Feliz, M. Jesús Fernández-Trujillo, Rosa Llusar and Vicent S. Safont

      Version of Record online: 22 DEC 2009 | DOI: 10.1002/chem.200902233

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      It′s down to the solvent! Proton transfer from acids to the coordinated hydride in the [W3PdS4H3(dmpe)3(CO)]+ cluster can go through a variety of reaction pathways that depend on the nature of the solvent. In noncoordinating solvents such as dichloromethane, the reaction goes through dihydrogen-bonded adducts with one and two acid molecules.

    16. Oxidation of Alkenes

      Efficient Aerobic Wacker Oxidation of Styrenes Using Palladium Bis(isonitrile) Catalysts (pages 1624–1628)

      Anu Naik, Liu Meina, Manfred Zabel and Oliver Reiser

      Version of Record online: 10 DEC 2009 | DOI: 10.1002/chem.200901560

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      No cocatalysts needed! Bidentate isonitrile ligands were synthesized from readily available oxazolines. Their palladium complexes proved to be effective in the oxidation of alkenes to give the corresponding ketones in high yield and selectivity (see scheme). Molecular oxygen at ambient pressure could be employed as the oxidant without the need of additional cocatalysts.

    17. Porous Materials

      Evolution of Helical Mesostructures (pages 1629–1637)

      Pei Yuan, Lingzhi Zhao, Nian Liu, Guangfeng Wei, Yunhua Wang, Graeme J. Auchterlonie, J. Drennan, Gao Qing Lu, Jin Zou and Chengzhong Yu

      Version of Record online: 10 DEC 2009 | DOI: 10.1002/chem.200902435

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      A simple transition: An evolution from a straight internal helical to hierarchical helical (HH) mesostructure with both internal and external helices or screwlike and concentric circular (CC) mesostructures is successfully observed. The HH structures with both internal and external helices are formed during the helix–coil transition process (region I; see picture). Structural mutation occurs in the restricted region (II), thus resulting in the complicated screwlike and CC mesostructures.

    18. Asymmetric Catalysis

      Chiral Brønsted Acid Directed Iron-Catalyzed Enantioselective Friedel–Crafts Alkylation of Indoles with β-Aryl α′-Hydroxy Enones (pages 1638–1645)

      Lei Yang, Qiming Zhu, Shengmei Guo, Bo Qian, Chungu Xia and Hanmin Huang

      Version of Record online: 23 DEC 2009 | DOI: 10.1002/chem.200902705

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      A tiny proton makes a big difference: A cooperative catalytic system established by the combination of an iron salt and a chiral Brønsted acid has proven to be effective in the asymmetric Friedel–Crafts alkylation of indoles with β-aryl α′-hydroxy enones. The reaction exhibits high catalytic activity and enantioselectivity (see scheme).

    19. Raman Spectroscopy

      Surface Dynamics of A Vanadyl Pyrophosphate Catalyst for n-Butane Oxidation to Maleic Anhydride: An In Situ Raman and Reactivity Study of the Effect of the P/V Atomic Ratio (pages 1646–1655)

      Fabrizio Cavani, Silvia Luciani, Elisa Degli Esposti, Carlotta Cortelli and Roberto Leanza

      Version of Record online: 9 DEC 2009 | DOI: 10.1002/chem.200902017

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      Phased out: The nature of the active layer in vanadyl pyrophosphate, a catalyst for n-butane oxidation to maleic anhydride, is a function of the atomic phosphorus/vanadium ratio in catalysts and of the temperature of reaction (see figure).

    20. Enantiodifferentiation

      Enhancing the Orienting Properties of Poly(γ-benzyl-L-glutamate) by means of Additives (pages 1656–1663)

      Andreas Marx, Benjamin Böttcher and Christina M. Thiele

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902287

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      Get tuned! The orienting properties of poly(γ-benzyl-L-glutamate) (PBLG) can be tuned by the use of additives. CCl4 allows for increased enantiodiscrimination, whereas DMSO makes the orientation of a salt, which is insoluble in chloroform (see figure), possible.

    21. Asymmetric Catalysis

      Highly Enantioselective Synthesis of β-Heteroaryl-Substituted Dihydrochalcones Through Friedel–Crafts Alkylation of Indoles and Pyrrole (pages 1664–1669)

      Wentao Wang, Xiaohua Liu, Weidi Cao, Jun Wang, Lili Lin and Xiaoming Feng

      Version of Record online: 10 DEC 2009 | DOI: 10.1002/chem.200902355

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      Scimply the best: A highly enantioselective Friedel–Crafts alkylation of indoles and pyrrole with chalcone derivatives catalyzed by a chiral N,N′-dioxide–ScIII complex has been developed (see scheme). The reaction tolerates a wide range of substrates and proceeds in moderate to excellent yields and high enantioselectivities (85–92 % ee).

    22. Bridged Palladacycles

      σ-Alkylpalladium Intermediates in Intramolecular Heck Reactions:Isolation and Catalytic Activity (pages 1670–1678)

      Egle M. Beccalli, Elena Borsini, Stefano Brenna, Simona Galli, Micol Rigamonti and Gianluigi Broggini

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902071

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      Heck intermediates: A series of novel bridged five-membered palladacycles (see picture) arising from intramolecular Heck cyclizations of N-allyl-2-halobenzylamines were isolated and purified. These σ-alkylpalladium complexes showed high stability to air, moisture, and heating. Moreover, they were proven to be effective precatalysts in Heck, Suzuki, and Stille reactions.

    23. Hydrogen Bonds

      Symmetrization of Cationic Hydrogen Bridges of Protonated Sponges Induced by Solvent and Counteranion Interactions as Revealed by NMR Spectroscopy (pages 1679–1690)

      Mariusz Pietrzak, Jens P. Wehling, Shushu Kong, Peter M. Tolstoy, Ilya G. Shenderovich, Concepción López, Rosa María Claramunt, José Elguero, Gleb S. Denisov and Hans-Heinrich Limbach

      Version of Record online: 18 DEC 2009 | DOI: 10.1002/chem.200902259

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      Chilled sponges: By using low-temperature NMR spectroscopy, the properties of the intramolecular hydrogen bonds of doubly 15N-labeled protonated sponges of the 1,8-bis(dimethylamino)naphthalene type (see image) have been studied as a function of the solvent, counteranion, and temperature.

    24. Covalent Hydrates

      Synthetic and Structural Studies on Copper 1 H-[1,10]-Phenanthrolin-2-one Coordination Complexes: Isolation of a Novel Intermediate During 1,10-Phenanthroline Hydroxylation (pages 1691–1696)

      Katherine B. Szpakolski, Kay Latham, Colin J. Rix, Jonathan M. White, Boujemaa Moubaraki and Keith S. Murray

      Version of Record online: 9 DEC 2009 | DOI: 10.1002/chem.200901720

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      Covalent hydrates code cracked? Here's Hophen: The synthesis and crystal structure elucidation of a novel intermediate dinuclear heteroleptic copper(II) complex (see figure), has led to the suggestion of an alternative mechanism in the formation of covalent hydrates.

    25. Diene Synthesis

      Applications of Allylsamarium Bromide as a Grignard Reagent and a Single-Electron Transfer Reagent in the One-Pot Synthesis of Dienes and Trienes (pages 1697–1705)

      Yuanyuan Hu, Tao Zhao and Songlin Zhang

      Version of Record online: 11 DEC 2009 | DOI: 10.1002/chem.200901927

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      Two in one! A general, efficient, and experimentally simple one-pot method for the preparation of 1,4-dienes and trienes is described. The utility of allylsamarium bromide simultaneously acting as a nucleophilic reagent and a single-electron transfer (SET) reagent is reported for the first time.

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    1. Top of page
    2. Cover Picture
    3. Graphical Abstract
    4. Corrigendum
    5. News
    6. Concept
    7. Communications
    8. Full Papers
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      Preview: Chem. Eur. J. 6/2010 (page 1709)

      Version of Record online: 26 JAN 2010 | DOI: 10.1002/chem.201090017

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