Angewandte Chemie International Edition

Cover image for Vol. 48 Issue 20

May 4, 2009

Volume 48, Issue 20

Pages 3541–3711

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. Cover Picture: Nanoscale Chemical Imaging of the Reduction Behavior of a Single Catalyst Particle (Angew. Chem. Int. Ed. 20/2009) (page 3541)

      Emiel de Smit, Ingmar Swart, J. Fredrik Creemer, Chithra Karunakaran, Drew Bertwistle, Henny W. Zandbergen, Frank M. F. de Groot and Bert M. Weckhuysen

      Version of Record online: 28 APR 2009 | DOI: 10.1002/anie.200990101

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      Iron-based catalysts for the Fischer–Tropsch synthesis bring about the conversion of synthesis gas (CO/H2) derived from coal or biomass into liquid transportation fuels. In their Communication on page 3632 ff., B. M. Weckhuysen, F. M. F. de Groot, and co-workers provide insights into the difference in behavior of the catalyst precursors during pretreatment in H2 on both the nanoscopic and the bulk scale. These findings enable further understanding of how the activated catalyst works.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. Inside Cover: Challenging the Metallocene Dominance in Actinide Chemistry with a Soft PNP Pincer Ligand: New Uranium Structures and Reactivity Patterns (Angew. Chem. Int. Ed. 20/2009) (page 3542)

      Thibault Cantat, Christopher R. Graves, Brian L. Scott and Jaqueline L. Kiplinger

      Version of Record online: 28 APR 2009 | DOI: 10.1002/anie.200990102

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      A standing iceberg illustrates how the soft PNP pincer ligand challenges the metallocene dominance (ship) in actinide chemistry, as described by J. L. Kiplinger and co-workers in their Communication on page 3681 ff. Replacement of C5Me5 by the PNP ligand is a successful strategy for the promotion of new reactivities and to support new actinide structures. The specific electronic and steric properties of the PNP ligand enable access to structures not available for the C5Me5 ligand set and as yet unreported for uranium. (We thank Mr. Anthony Mancinco for the design of the graphic.)

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
  4. News

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
  5. Author Profile

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. V. Gouverneur (page 3559)

      Version of Record online: 28 APR 2009 | DOI: 10.1002/anie.200901599

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      „The biggest challenge facing scientists is finding a way to make clean energy. If I could have dinner with three famous scientists from history, they would be Marie Curie, Dmitri Mendeleev, and Henri Moissan. …“ This and more about Véronique Gouverneur can be found on page 3559.

  6. Book Reviews

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. Modern Supramolecular Gold Chemistry.Gold-Metal Interactions and Applications. Edited by A. Laguna. (page 3560)

      Richard J. Puddephatt

      Version of Record online: 28 APR 2009 | DOI: 10.1002/anie.200900872

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      Wiley-VCH, Weinheim 2008. 505 pp., hardcover € 159.00.—ISBN 978-352732095

    2. The Power of Functional Resins in Organic Synthesis.Edited by Judit Tulla-Puche and Fernando Albericio. (pages 3560–3561)

      Rolf Breinbauer

      Version of Record online: 28 APR 2009 | DOI: 10.1002/anie.200900955

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      Wiley-VCH, Weinheim 2008. 663 pp., hardcover € 159.00.—ISBN 978-3527319367

  7. Highlights

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. Polyoxometalates

      Are Particulate Noble-Metal Catalysts Metals, Metal Oxides, or Something In-Between? (pages 3562–3564)

      James C. Goloboy and Walter G. Klemperer

      Version of Record online: 12 MAR 2009 | DOI: 10.1002/anie.200805382

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      A good model? Noble-metal particulate catalysts often require small amounts of oxygen to obtain optimal activity. However, the structure and stoichiometry of the oxidized metal clusters involved remains obscure, even almost two hundred years after their discovery. A heteropolypalladate salt (see picture; Pd yellow, O red) now offers a view of how oxygen might be incorporated into small noble-metal clusters.

    2. Cross-Coupling

      Devising Boron Reagents for Orthogonal Functionalization through Suzuki–Miyaura Cross-Coupling (pages 3565–3568)

      Mamoru Tobisu and Naoto Chatani

      Version of Record online: 23 MAR 2009 | DOI: 10.1002/anie.200900465

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      Seeing the sites: The Suzuki–Miyaura reaction of substrates containing multiple coupling sites has been performed in a directed manner through the reactivity modulation of the boron moiety (see scheme). Several other strategies are also discussed.

    3. C[BOND]O Activation

      C(aryl)[BOND]O Activation of Aryl Carboxylates in Nickel-Catalyzed Biaryl Syntheses (pages 3569–3571)

      Lukas J. Gooßen, Käthe Gooßen and Corneliu Stanciu

      Version of Record online: 11 MAR 2009 | DOI: 10.1002/anie.200900329

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      Crucial breakthroughs in the activation of the C(aryl)[BOND]O bond of phenol derivatives were achieved almost simultaneously by two research groups (see scheme; Cy=cyclohexyl). Garg et al. coupled a range of aryl pivalates with arylboronic acids to give unsymmetrical biaryls. Shi et al. achieved this through C(aryl)[BOND]O activation of aryl carboxylates; the best results for the coupling of aryl boroxines were again obtained with aryl pivalates.

  8. Minireview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. Luminescent Materials

      Recent Developments in the Field of Inorganic Phosphors (pages 3572–3582)

      Henning A. Höppe

      Version of Record online: 6 APR 2009 | DOI: 10.1002/anie.200804005

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      Energy efficiency is in! New inorganic luminescent materials can help to increase energy efficiency when used in plasma display panels and white-light-emitting diodes (see color diagram; mixing the three emissions A–C produces any given point within the triangle). In mercury-free fluorescent lamps these phosphors might contribute to environmental protection, and they provide better scintillation materials for medical diagnostics.

  9. Reviews

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. Biomimetic Polymers

      Spider Silk: From Soluble Protein to Extraordinary Fiber (pages 3584–3596)

      Markus Heim, David Keerl and Thomas Scheibel

      Version of Record online: 11 FEB 2009 | DOI: 10.1002/anie.200803341

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      On a silky thread: Spider silks have mechanical properties that outperform most natural and synthetic fibers. Classical spinning methods have failed to mimic the highly complex natural in-vivo spinning process. Analyzing this process in combination with in-vitro findings allows the development of biomimetic spinning devices for the technical production of silk fibers (see picture).

    2. Telomerization

      Telomerization: Advances and Applications of a Versatile Reaction (pages 3598–3614)

      Arno Behr, Marc Becker, Thomas Beckmann, Leif Johnen, Julia Leschinski and Sebastian Reyer

      Version of Record online: 3 MAR 2009 | DOI: 10.1002/anie.200804599

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      A chameleonic reaction: The transition-metal-catalyzed telomerization of 1,3-dienes with different nucleophiles leads to the synthesis of numerous products which can be applied in the cosmetic and pharmaceutical industry as well as in polymers and flavors. This Review shows the versatility of the telomerization based on recent research and industrial applications.

  10. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview
    1. Phosphorus Nanostructures

      Synthesis of Pure Phosphorus Nanostructures (pages 3616–3621)

      Richard A. L. Winchester, Max Whitby and Milo S. P. Shaffer

      Version of Record online: 29 JAN 2009 | DOI: 10.1002/anie.200805222

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      To Bi or not to Bi? The synthesis of phosphorus nanorods of two differing morphologies is reported, in both the presence and absence of a bismuth catalyst. Not only do these materials represent a new class of elemental nanorods but they also give valuable insight into the complex allotropy of phosphorus.

    2. Nonheme Iron Complexes

      A Synthetic High-Spin Oxoiron(IV) Complex: Generation, Spectroscopic Characterization, and Reactivity (pages 3622–3626)

      Jason England, Marlène Martinho, Erik R. Farquhar, Jonathan R. Frisch, Emile L. Bominaar, Eckard Münck and Lawrence Que Jr.

      Version of Record online: 16 APR 2009 | DOI: 10.1002/anie.200900863

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      High versus low: The high-yield generation of a synthetic high-spin oxoiron(IV) complex, [FeIV(O)(TMG3tren)]2+ (see picture, TMG3tren = 1,1,1-tris{2-[N2-(1,1,3,3-tetramethylguanidino)]ethyl}amine), has been achieved by using the very bulky tetradentate TMG3tren ligand, in order to both sterically protect the oxoiron(IV) moiety and enforce a trigonal bipyramidal geometry at the iron center, for which an S=2 ground state is favored.

    3. Asymmetric Synthesis

      Synthesis of a Chiral Quaternary Carbon Center Bearing a Fluorine Atom: Enantio- and Diastereoselective Guanidine-Catalyzed Addition of Fluorocarbon Nucleophiles (pages 3627–3631)

      Zhiyong Jiang, Yuanhang Pan, Yujun Zhao, Ting Ma, Richmond Lee, Yuanyong Yang, Kuo-Wei Huang, Ming Wah Wong and Choon-Hong Tan

      Version of Record online: 17 APR 2009 | DOI: 10.1002/anie.200900964

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      The perfect combination: The title reaction provides adducts having quaternary carbon centers bearing a fluorine atom with high ee and d.r. values (see scheme). The mechanism and origin of stereoselectivity were elucidated by DFT calculations. The bifunctional mode of the guanidine catalysis was demonstrated in the transition states resulting from the DFT results.

    4. Heterogeneous Catalysis

      Nanoscale Chemical Imaging of the Reduction Behavior of a Single Catalyst Particle (pages 3632–3636)

      Emiel de Smit, Ingmar Swart, J. Fredrik Creemer, Chithra Karunakaran, Drew Bertwistle, Henny W. Zandbergen, Frank M. F. de Groot and Bert M. Weckhuysen

      Version of Record online: 10 FEB 2009 | DOI: 10.1002/anie.200806003

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      A closer look: Investigation of the reduction properties of a single Fischer–Tropsch catalyst particle, using in situ scanning transmission X-ray microscopy with spatial resolution of 35 nm, reveals a heterogeneous distribution of Fe0, Fe2+, and Fe3+ species. Regions of different reduction properties are defined and explained on the basis of local chemical interactions and catalyst morphology.

    5. Metal–Organic Frameworks

      Unusual Interlocking and Interpenetration Lead to Highly Porous and Robust Metal–Organic Frameworks (pages 3637–3640)

      Liqing Ma and Wenbin Lin

      Version of Record online: 7 APR 2009 | DOI: 10.1002/anie.200806227

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      Stop the breathing: As the organic bridging ligands become more elaborate and large, the resulting MOFs tend to experience significant framework distortion (i.e., breathing) upon solvent removal. Rigidification of MOFs that are built from elongated tetracarboxylate bridging ligands by unusual interlocking and interpenetration leads to highly porous and robust hybrid materials.

    6. Molecular Imaging

      Dual-Function Probe to Detect Protease Activity for Fluorescence Measurement and 19F MRI (pages 3641–3643)

      Shin Mizukami, Rika Takikawa, Fuminori Sugihara, Masahiro Shirakawa and Kazuya Kikuchi

      Version of Record online: 7 APR 2009 | DOI: 10.1002/anie.200806328

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      Dynamic duo: Magnetic resonance imaging (MRI) can visualize deep regions of living bodies, whereas fluorescence measurement offers excellent sensitivity. These methods thus offer signal enhancement potential for detecting enzyme activities. A dual-mode off/on probe to detect caspase-3 activity by fluorescence and 19F MRI is presented.

    7. Synthetic Methods

      Iridium Catalysis for C[BOND]H Bond Arylation of Heteroarenes with Iodoarenes (pages 3644–3647)

      Benoît Join, Takuya Yamamoto and Kenichiro Itami

      Version of Record online: 7 APR 2009 | DOI: 10.1002/anie.200806358

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      Efficient couplings using equimolar quantities of each coupling partner and multiple C[BOND]H bond arylation reactions are achieved with an Ir-based catalytic system for the C[BOND]H bond arylation of electron-rich heteroarenes with iodoarenes to construct extended π-systems. The dramatic ligand effect on reaction efficiency leads to the discovery that Crabtree's catalyst (see scheme) is the optimal catalyst precursor.

    8. Complex Allylation by the Direct Cross-Coupling of Imines with Unactivated Allylic Alcohols (pages 3648–3652)

      Masayuki Takahashi, Martin McLaughlin and Glenn C. Micalizio

      Version of Record online: 9 APR 2009 | DOI: 10.1002/anie.200900236

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      Regioselective, stereoselective: The convergent coupling of allylic alcohols with imines to deliver stereodefined homoallylic amines is described (see scheme). The process proceeds with net allylic transposition without the intermediacy of allylic organometallic reagents. Two stereodefined centers and a geometrically defined di- or trisubstituted alkene are forged with high selectivity.

    9. Fluorescent Materials

      1,4-Bis(alkenyl)-2,5-dipiperidinobenzenes: Minimal Fluorophores Exhibiting Highly Efficient Emission in the Solid State (pages 3653–3656)

      Masaki Shimizu, Youhei Takeda, Masahiro Higashi and Tamejiro Hiyama

      Version of Record online: 7 APR 2009 | DOI: 10.1002/anie.200900963

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      Minimum requirements: Crystals and thin films of 1,4-bis(alkenyl)-2,5-dipiperidinobenzenes, which contain only one benzene ring as the aromatic component, emit visible light with excellent solid-state quantum yields upon irradiation with UV light. Polystyrene thin films doped with the benzenes also exhibit brilliant fluorescence. By modifying the alkenyl groups, the emission color can be tuned in the range from blue to red.

    10. Nanotubes

      Reversible Scrolling of Two-Dimensional Sheets from the Self-Assembly of Laterally Grafted Amphiphilic Rods (pages 3657–3660)

      Eunji Lee, Jung-Keun Kim and Myongsoo Lee

      Version of Record online: 16 APR 2009 | DOI: 10.1002/anie.200900079

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      Deep-water scrolls: It is demonstrated that amphiphilic rods containing lateral flexible chains self-assemble into two-dimensional sheets in aqueous solution (see picture). Remarkably, the sheets roll up reversibly into tubular scrolls upon heating, as confirmed by cryo-transmission electron microscopy and fluorescence microscopy.

    11. Nanostructures

      Silver Nanoparticle Formation in Different Sizes Induced by Peptides Identified within Split-and-Mix Libraries (pages 3661–3664)

      Kirsten Belser, Tünde Vig Slenters, Conelious Pfumbidzai, Grégory Upert, Laurent Mirolo, Katharina M. Fromm and Helma Wennemers

      Version of Record online: 16 APR 2009 | DOI: 10.1002/anie.200806265

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      Split-and-mix libraries are an excellent tool for the identification of peptides that induce the formation of Ag nanoparticles in the presence of either light or sodium ascorbate to reduce Ag+ ions. Structurally diverse peptides were detected in colorimetric on-bead screenings that generate Ag nanoparticles of different sizes, as confirmed by SEM and X-ray powder diffraction studies.

    12. Microdroplets

      Coupling Microdroplet Microreactors with Mass Spectrometry: Reading the Contents of Single Droplets Online (pages 3665–3668)

      Luis M. Fidalgo, Graeme Whyte, Brandon T. Ruotolo, Justin L. P. Benesch, Florian Stengel, Chris Abell, Carol V. Robinson and Wilhelm T. S. Huck

      Version of Record online: 7 APR 2009 | DOI: 10.1002/anie.200806103

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      Fully integrated: Mass spectrometry has been integrated into a detection scheme for microdroplets that are created within microfluidic channels (see picture, scale bar 200 μm). This technique allows droplets to be identified based on the compounds they contain, and combines fluorescence screening with MS analysis. These experiments indicate how similar approaches can be applied to the ambitious goals of on-chip protein evolution and chemical synthesis.

    13. CO Analogues

      Coordination and Activation of the BF Molecule (pages 3669–3672)

      Dragoslav Vidovic and Simon Aldridge

      Version of Record online: 16 APR 2009 | DOI: 10.1002/anie.200901022

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      No CO: Fluoroborylene (BF), isoelectronic with CO and N2, can be trapped by a transition metal. The structurally characterized complex [{CpRu(CO)2}2(μ-BF)] contains an unsupported bridging BF ligand, which is unprecedented in the structural chemistry of CO. With AlCl3 , metal-bound CO coordinates through the O atom without bond rupture, while the more polar and less π-bonded BF ligand is heterolytically cleaved (see picture).

    14. Heterogeneous Catalysis

      High Catalytic Activity of Palladium(II)-Exchanged Mesoporous Sodalite and NaA Zeolite for Bulky Aryl Coupling Reactions: Reusability under Aerobic Conditions (pages 3673–3676)

      Minkee Choi, Dong-Hwan Lee, Kyungsu Na, Byung-Woo Yu and Ryong Ryoo

      Version of Record online: 9 APR 2009 | DOI: 10.1002/anie.200806334

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      Exchange for the better: Mesoporous sodalite and NaA zeolite exchanged with Pd2+ exhibit remarkably high activity and reusability in C[BOND]C coupling reactions under aerobic atmosphere. It is proposed that the catalytic reactions are mediated by a molecular Pd0 species generated in situ within the pores (see picture), which is oxidized back to Pd2+ by O2, preventing the formation of catalytically inactive Pd0 agglomerates.

    15. Synthetic Methods

      Palladium-Catalyzed Insertion of α-Diazoesters into Vinyl Halides To Generate α,β-Unsaturated γ-Amino Esters (pages 3677–3680)

      Romas Kudirka, Sean K. J. Devine, Christopher S. Adams and David L. Van Vranken

      Version of Record online: 7 APR 2009 | DOI: 10.1002/anie.200805483

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      As easy as 1, 2, 3: A palladium-catalyzed three-component coupling generates α,β-unsaturated γ-amino acids in a single step (see scheme). The reaction is believed to involve migration of a vinyl substituent to a highly electrophilic palladium carbene. Unlike previous synthetic approaches, this synthesis provides access to γ-amino acids with non-natural side chains.

    16. Actinide Chemistry

      Challenging the Metallocene Dominance in Actinide Chemistry with a Soft PNP Pincer Ligand: New Uranium Structures and Reactivity Patterns (pages 3681–3684)

      Thibault Cantat, Christopher R. Graves, Brian L. Scott and Jaqueline L. Kiplinger

      Version of Record online: 16 FEB 2009 | DOI: 10.1002/anie.200806115

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      A soft embrace for U: Replacement of C5Me5 by the soft PNP pincer ligand is a successful strategy to promote new reactivities and support new structures for the actinide series (see picture, py–O=pyridine-N-oxide). The specific electronic and steric properties of the PNP ligand enable access to previously unreported structures not available for the C5Me5 ligand set and support not only low-valent uranium but also the high-valent uranium(VI) ion.

    17. Natural Products Synthesis

      Formal Total Synthesis of Platencin (pages 3685–3688)

      Georgy N. Varseev and Martin E. Maier

      Version of Record online: 7 APR 2009 | DOI: 10.1002/anie.200900447

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      The right bicycle: A concise formal synthesis of platencin was based on an efficient oxygen-mediated palladium-catalyzed cycloalkenylation of 1 to form a bicyclo[3.2.1]octane, and a deoxygenative rearrangement of tosylhydrazone 2 to construct the bicyclo[2.2.2]octane 3. The total yield of the core structure 4 of platencin was 17.5 % for 13 steps from a commercially available compound. Ts=p-toluenesulfonyl, TBS=tert-butyldimethylsilyl, Piv=pivaloyl.

    18. Multicomponent Reactions

      Diastereoselective Synthesis of Pentasubstituted γ-Butyrolactones from Silyl Glyoxylates and Ketones through a Double Reformatsky Reaction (pages 3689–3691)

      Stephen N. Greszler and Jeffrey S. Johnson

      Version of Record online: 16 APR 2009 | DOI: 10.1002/anie.200900215

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      Three contiguous stereocenters can be established with remarkable diastereoselectivity in a double Reformatsky sequence. Densely functionalized γ-butyrolactones were assembled rapidly by this approach, in which a ketone is used as the terminal electrophile (see scheme). Secondary transformations of the lactone products enhance their synthetic utility. R1=Me, H; R2=alkyl, aryl, CF3; Bn=benzyl, TBS=tert-butyldimethylsilyl.

    19. Catalytic Promiscuity

      Efficient Catalytic Promiscuity for Chemically Distinct Reactions (pages 3692–3694)

      Ann C. Babtie, Subhajit Bandyopadhyay, Luis F. Olguin and Florian Hollfelder

      Version of Record online: 16 APR 2009 | DOI: 10.1002/anie.200805843

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      High catalytic proficiencies observed for the native and promiscuous reaction of the Pseudomonas aeruginosa arylsulfatase (PAS; the picture shows transition states of the two substrates with corresponding binding constants Ktx) suggest that the trade-off between high activity and tight specificity can be substantially relaxed.

    20. Surface Chemistry

      Formaldehyde Formation on Vanadium Oxide Surfaces V2O3(0001) and V2O5(001): How does the Stable Methoxy Intermediate Form? (pages 3695–3698)

      Daniel Göbke, Yuriy Romanyshyn, Sébastien Guimond, Jacobus Marinus Sturm, Helmut Kuhlenbeck, Jens Döbler, Ulrike Reinhardt, Maria Veronica Ganduglia-Pirovano, Joachim Sauer and Hans-Joachim Freund

      Version of Record online: 16 APR 2009 | DOI: 10.1002/anie.200805618

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      Hydroxy-mediated methoxy formation or stabilization is probably an important process in many methanol adsorption systems. Hydrogen atoms originating from the scission of the methanol O[BOND]H bond react with the substrate and form water. This process may result 1) in the production of additional surface defects as reactive centers for methoxy formation and 2) in the stabilization of methoxy groups by suppression of methanol formation.

    21. Asymmetric Domino Catalysis

      Asymmetric Organocatalytic Domino Michael/Aldol Reactions: Enantioselective Synthesis of Chiral Cycloheptanones, Tetrahydrochromenones, and Polyfunctionalized Bicyclo[3.2.1]octanes (pages 3699–3702)

      Magnus Rueping, Alexander Kuenkel, Francisco Tato and Jan W. Bats

      Version of Record online: 17 APR 2009 | DOI: 10.1002/anie.200900754

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      C′mon 1,2-dione: A new diastereo- and enantioselective Lewis base catalyzed domino Michael/aldol reaction converts α,β-unsaturated aldehydes and 1,2-diones into chiral bicyclo[3.2.1]octane-6-carbaldehydes. The products are produced in good to excellent enantioselectivities (90–98 % ee) and can be transformed into bicyclic diols and triols. Additionally, a retro-aldol cyclization provides access to valuable tetrahydrochromenones (see scheme).

    22. Fe[BOND]Fe Dimer with Redox-Active Ligands

      [{Fe(tim)}2]: An Fe[BOND]Fe Dimer Containing an Unsupported Metal–Metal Bond and Redox-Active N4 Macrocyclic Ligands (pages 3703–3706)

      Corinna R. Hess, Thomas Weyhermüller, Eckhard Bill and Karl Wieghardt

      Version of Record online: 17 APR 2009 | DOI: 10.1002/anie.200900725

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      Mixed doubles: The dimeric complex [{Fe(tim)}2] (see structure, tim=2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene) represents an unprecedented complex containing an unsupported Fe[BOND]Fe bond. The crystal structure confirms the presence of reduced tim units, thus indicating ligand redox activity. Spectroscopic and computational studies establish a triplet ground state for [{Fe(tim)}2] and suggest a mixed-valence compound with respect to both the Fe ions and the ligands.

  11. Preview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. Book Reviews
    8. Highlights
    9. Minireview
    10. Reviews
    11. Communications
    12. Preview

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