Angewandte Chemie International Edition

Cover image for Vol. 46 Issue 44

November 12, 2007

Volume 46, Issue 44

Pages 8305–8519

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Cover Picture: Crystal Engineering: A Holistic View (Angew. Chem. Int. Ed. 44/2007) (page 8305)

      Gautam R. Desiraju

      Version of Record online: 2 NOV 2007 | DOI: 10.1002/anie.200790222

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      What determines the crystal structure, intermolecular interactions or close packing? This dichotomy recurs in crystal engineering, which attempts to understand complexity in molecular solids, as described by G. R. Desiraju in the Review on page 8342 ff. The cover picture shows that while the iodine atoms (blue) are in contact in 1,3,5-trichloro-2,4,6-triiodobenzene, the chlorine atoms (green) are not. The background shows a massive stone wheel of the sun god's chariot in the Konarak temple, symbolizing the scientist's quest for the eternal truth between the atom and the absolute.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Inside Cover: A Millimeter-Wave Absorber Based on Gallium-Substituted ε-Iron Oxide Nanomagnets (Angew. Chem. Int. Ed. 44/2007) (page 8306)

      Shin-ichi Ohkoshi, Shiro Kuroki, Shunsuke Sakurai, Kazuyuki Matsumoto, Kimitaka Sato and Shinya Sasaki

      Version of Record online: 2 NOV 2007 | DOI: 10.1002/anie.200790223

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      Millimeter waves , with a range of 30–300 GHz, are beginning to be used in electronic devices for high-speed wireless communications. In their Communication on page 8392 ff., S. Ohkoshi et al. report a new millimeter-wave absorber composed of ε-GaxFe2−xO3 (0.10≤x≤0.67) nanomagnets, which shows a ferromagnetic resonance in the 35–190-GHz region. The picture shows a Japanese landscape garden, Zuiho-in in Kyoto, in which the center rock, the ripples of sand, and the near rock evoke a millimeter-wave generator, millimeter waves, and the millimeter-wave absorber, respectively.

  3. Graphical Abstract

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

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Nobel Prize 2007 (page 8326)

      Version of Record online: 2 NOV 2007 | DOI: 10.1002/anie.200704723

  5. Book Reviews

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

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. 3D Nanoscopy: Bringing Biological Nanostructures into Sharp Focus (pages 8330–8332)

      Peter Dedecker, Cristina Flors, Jun-ichi Hotta, Hiroshi Uji-i and Johan Hofkens

      Version of Record online: 17 OCT 2007 | DOI: 10.1002/anie.200703314

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      Zooming in: Ultrahigh-resolution microscopy is developing rapidly by different approaches. Photoactivation–localization microscopy (PALM) can now provide 3D images with fast acquisition times through the use of photoactivatable rhodamines and two-photon excitation. In PALM, individual emitters can be localized with nanometer precision simply by determining the centroid of the emission distribution.

  7. Minireview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Learning from Nature: β-Sheet-Mimicking Copolymers Get Organized (pages 8334–8340)

      Hannah M. König and Andreas F. M. Kilbinger

      Version of Record online: 2 OCT 2007 | DOI: 10.1002/anie.200701167

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      Folding sheets: Organizing polymers with the help of β-sheet peptides is an emerging field of polymer research. The peptides employed to date range from linear and cyclic α peptides to fully synthetic peptide analogues. Nature's most basic lesson of secondary structure formation has been learned. Predicting the higher levels of hierarchical organization of peptide–copolymer aggregates will be the topic of the many lessons to come.

  8. Review

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Crystal Engineering: A Holistic View (pages 8342–8356)

      Gautam R. Desiraju

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200700534

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      A crystal structure is a complex convolution of molecular structure and is hard to predict. Crystals are formed under thermodynamic or kinetic control. This dichotomy leads to polymorphism and further difficulties. This review surveys some recent challenges in the design of functional solid-state molecular materials. The picture shows experimental and computer-predicted crystal structures for 3-amino-2-naphthol.

  9. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Molecular Cosensitization for Efficient Panchromatic Dye-Sensitized Solar Cells (pages 8358–8362)

      Juan-José Cid, Jun-Ho Yum, Song-Rim Jang, Mohammad K. Nazeeruddin, Eugenia Martínez-Ferrero, Emilio Palomares, Jaejung Ko, Michael Grätzel and Tomás Torres

      Version of Record online: 2 OCT 2007 | DOI: 10.1002/anie.200703106

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      Dyeing together: An efficient panchromatic dye-sensitized solar cell is constructed by using a “molecular cocktail” composed of an organic dye and a zinc phthalocyanine (see picture). The use of multiple, complementary dyes (cosensitization) is an important step towards solar cells that operate across the full spectrum of solar irradiation.

    2. Synthesis of Heterodimeric Sphere–Prism Nanostructures via Metastable Gold Supraspheres (pages 8363–8367)

      Rafal Klajn, Anatoliy O. Pinchuk, George C. Schatz and Bartosz A. Grzybowski

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200702570

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      Changing shapes: Metastable spherical aggregates of gold nanoparticles undergo a one-to-one, thermally induced transformation into heterodimers comprising connected plate and spherical domains. By controlling the reaction time, it is possible to isolate a variety of structures differing in the relative sizes of the domains and in the overall optical properties (see picture).

    3. Simple Heme Dimers with Strongly Cooperative Ligand Binding (pages 8368–8370)

      Daria Khvostichenko, Qing-Zheng Yang and Roman Boulatov

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200702120

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      Two is better than one: FeII complexes of new porphyrins exist as dimers that bind small ligands cooperatively, as illustrated by the sigmoidal binding curve (fractional occupancy of binding sites, α, versus free-ligand concentration, x) for isocyanide Me2C6H3NC. An allosteric interaction energy of up to 13 kJ mol−1—comparable to that of hemoglobin—is achieved in a simple structural motif.

    4. Mercury Is a Transition Metal: The First Experimental Evidence for HgF4 (pages 8371–8375)

      Xuefang Wang, Lester Andrews, Sebastian Riedel and Martin Kaupp

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200703710

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      A new take on quicksilver: The elements of Group 12 are generally considered post-transition metals with filled d shells. However, calculations predict d8 HgF4 (see plot of the electron localization function) to be stable. IR spectroscopy in solid neon and argon matrixes gives first experimental evidence for HgF4. As HgIV, mercury would be a true transition metal that fully utilizes its 5d orbitals in bonding.

    5. A Concave-Bound CpFe Complex of Sumanene as a Metal in a π Bowl (pages 8376–8379)

      Toru Amaya, Hiroyuki Sakane and Toshikazu Hirao

      Version of Record online: 1 OCT 2007 | DOI: 10.1002/anie.200702826

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      Dished up: The selective synthesis of a concave-bound iron complex was achieved by ligand exchange of a cyclopentadienyl ring of ferrocene with a fullerene-fragment π bowl, sumanene (see picture). The concave π surface serves as an η6 ligand.

    6. Solid-State Protein-Structure Determination with Proton-Detected Triple-Resonance 3D Magic-Angle-Spinning NMR Spectroscopy (pages 8380–8383)

      Donghua H. Zhou, John J. Shea, Andrew J. Nieuwkoop, W. Trent Franks, Benjamin J. Wylie, Charles Mullen, Dennis Sandoz and Chad M. Rienstra

      Version of Record online: 1 OCT 2007 | DOI: 10.1002/anie.200702905

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      Spinning a magical web: The combination of fast magic-angle spinning, isotopic dilution, and high magnetic field yields particularly well-resolved solid-state 1H NMR spectra, which are efficiently utilized to solve protein structure. New techniques are demonstrated, requiring only three days of data collection, to assign the proton signals and solve a high-resolution structure of microcrystalline GB1.

    7. Recognition of “Mirror-Image” DNA by Small Molecules (pages 8384–8387)

      Christian Dose, Dominik Ho, Hermann E. Gaub, Peter B. Dervan and Christian H. Albrecht

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200703007

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      May the force be with you: “Mirror-image” hairpin polyamides distinguish the L enantiomer of DNA (L-DNA) in the presence of natural DNA (D-DNA). This specificity is investigated by a molecular force balance at a single-molecule level. The “DNA balance” allows the measurement of rupture forces of match/mismatch diastereomeric complexes in a single experiment.

    8. Organic Cation and Chiral Anion Templated 3D Homochiral Open-Framework Materials with Unusual Square-Planar {M4(OH)} Units (pages 8388–8391)

      Jian Zhang, Rui Liu, Pingyun Feng and Xianhui Bu

      Version of Record online: 25 SEP 2007 | DOI: 10.1002/anie.200703008

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      The zeolite way: Templating on charged organic species, which have long been used for synthesizing aluminosilicate zeolites, is shown to allow the self-assembly of enantiopure chiral molecular precursors into extended homochiral frameworks (see picture; Cd green, O red, C gray; the sky-blue spheres illustrate the open regions in the channels).

    9. A Millimeter-Wave Absorber Based on Gallium-Substituted ε-Iron Oxide Nanomagnets (pages 8392–8395)

      Shin-ichi Ohkoshi, Shiro Kuroki, Shunsuke Sakurai, Kazuyuki Matsumoto, Kimitaka Sato and Shinya Sasaki

      Version of Record online: 17 OCT 2007 | DOI: 10.1002/anie.200703010

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      Restraining electromagnetic interference in the millimeter-wave region has been accomplished with a new electromagnetic absorber composed of ε-GaxFe2−xO3 (0.10≤x≤0.67) nanomagnets, which shows a ferromagnetic resonance in the range 35–147 GHz. The possibility that the ferromagnetic resonance can achieve a frequency of 190 GHz at x[RIGHTWARDS ARROW]0 is also suggested. See picture: Hc=coercive field; fr=ferromagnetic resonance frequency.

    10. Target-Selective Degradation of Oligosaccharides by a Light-Activated Small-Molecule–Lectin Hybrid (pages 8396–8399)

      Maiko Ishii, Shuichi Matsumura and Kazunobu Toshima

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200702127

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      An innovative method for target-selective degradation of oligosaccharides induced by a light-activated hybrid molecule consisting of anthraquinone and lectin has been developed (see scheme). The reaction takes place under neutral conditions, and no additives are required. PNA=peanut agglutinin.

    11. Closed Mechanoelectrochemical Cycles of Individual Single-Chain Macromolecular Motors by AFM (pages 8400–8404)

      Weiqing Shi, Marina I. Giannotti, Xi Zhang, Mark A. Hempenius, Holger Schönherr and G. Julius Vancso

      Version of Record online: 1 OCT 2007 | DOI: 10.1002/anie.200702387

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      Motor cycles: Mechanoelectrochemical loops of single-chain macromolecular motors based on individual end-grafted poly(ferrocenyldimethylsilane) are shown by AFM to have an efficiency of up to 26 %. Upon oxidation of a prestretched chain, the chain length increases and the force decreases significantly as a result of intramolecular electrostatic repulsion between oxidized ferrocene units (see picture).

    12. A Code for Lysine Modifications of a Silica Biomineralizing Silaffin Protein (pages 8405–8408)

      Manfred Sumper, Robert Hett, Gerhard Lehmann and Stephan Wenzl

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200702413

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      A mass of codes: Lysine-rich silaffin proteins from diatoms guide silica formation by self-assembly processes. Aided by mass spectrometry, the analysis of 28 posttranslationally modified lysine residues in silaffin-3 from Thalassiosira pseudonana uncovers an amino acid sequence based code selecting the type of modification. This code may be a key element in the genetic control of species-specific silica architectures.

    13. Functional G-Quartet Macroscopic Membrane Films (pages 8409–8413)

      Carole Arnal-Hérault, Andreea Pasc, Mathieu Michau, Didier Cot, Eddy Petit and Mihail Barboiu

      Version of Record online: 2 OCT 2007 | DOI: 10.1002/anie.200702605

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      Transport systems: Long-range amplification of G-quadruplex self-organization by K+ ion templating into double dynameric macroscopic films is described. The ordered membrane films (see image) contribute to fast electron/proton or Na+/K+ transport by the formation of directional conduction pathways.

    14. Engineered Alkane-Hydroxylating Cytochrome P450BM3 Exhibiting Nativelike Catalytic Properties (pages 8414–8418)

      Rudi Fasan, Mike M. Chen, Nathan C. Crook and Frances H. Arnold

      Version of Record online: 20 SEP 2007 | DOI: 10.1002/anie.200702616

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      Divide, evolve, and conquer: A domain-based strategy (see scheme) was used to engineer high catalytic and coupling efficiency for propane hydroxylation in a multidomain cytochrome P450 enzyme. The engineered enzymes exhibit high total activities in whole-cell bioconversions of propane to propanol under mild conditions, using air as oxidant.

    15. Connectivity of the Chiral D2-Symmetric Isomer of C76 through a Crystal-Structure Determination of C76Cl18⋅TiCl4 (pages 8419–8421)

      Kalin S. Simeonov, Konstantin Yu. Amsharov and Martin Jansen

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200702632

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      A chiral fullerene: The first ordered crystal structure of a derivative of the D2-symmetric C76 fullerene, C76Cl18, is determined. The distorted carbon skeleton of C76Cl18 contains elongated C[BOND]C bonds and a unique π system. The C76 cage (see picture; green) is surrounded by two helical belts of chlorine atoms (orange).

    16. Solid-Phase Library Synthesis of Polyynes Similar to Natural Products (pages 8422–8425)

      Seonwoo Lee, Taeho Lee, Yun Mi Lee, Deukjoon Kim and Sanghee Kim

      Version of Record online: 25 SEP 2007 | DOI: 10.1002/anie.200703208

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      High in polyunsaturates: The combinatorial synthesis of a 65-membered polyyne library has been achieved by using an iterative acetylene homologation strategy combined with a solid support (see scheme). The library was evaluated against cancer cells to demonstrate its possible utility as a chemical tool to unravel cellular processes or as a platform for drug discovery and design.

    17. A Zirconium Hydrazide as a Synthon for a Metallanitrene Equivalent: Atom-by-Atom Assembly of [EN2]2− Units (E=S, Se) by Chalcogen-Atom Transfer in the Coordination Sphere of a Transition Metal (pages 8426–8430)

      Heike Herrmann, Julio Lloret Fillol, Hubert Wadepohl and Lutz H. Gade

      Version of Record online: 8 OCT 2007 | DOI: 10.1002/anie.200703938

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      Piece by piece: Hydrazides at zirconium centers undergo facile N[BOND]N bond cleavage and react as equivalents for metallanitrenes, thus allowing the atom-by-atom assembly of bridging dinitridosulfate(IV) and dinitridoselenate(IV) ligands (see scheme; TBS=tBuMe2Si).

    18. Water-Compatible Iminium Activation: Organocatalytic Michael Reactions of Carbon-Centered Nucleophiles with Enals (pages 8431–8435)

      Claudio Palomo, Aitor Landa, Antonia Mielgo, Mikel Oiarbide, Ángel Puente and Silvia Vera

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200703261

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      A pool of water-compatible catalysts, namely the chiral prolinol-based catalysts 1, has been developed for highly enantioselective C[BOND]C bond-forming Michael reactions in water (see scheme). The synthesis of (S)-Rolipram, a type IV phosphodiesterase inhibitor, was also demonstrated.

    19. Plasmon-Driven Synthesis of Triangular Core–Shell Nanoprisms from Gold Seeds (pages 8436–8439)

      Can Xue, Jill E. Millstone, Shuyou Li and Chad A. Mirkin

      Version of Record online: 2 OCT 2007 | DOI: 10.1002/anie.200703185

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      Outside silver, inside gold: Gold nanoparticles are used as seeds to probe the role of plasmon excitation in the photomediated growth of silver nanoprisms. This approach generates novel core–shell nanostructures that contain a spherical (see TEM image, inset shows side view) or triangular-prism gold core with a triangular silver prism shell. The architecture of these particles can be tuned by controlling the excitation wavelength and gold-core diameter.

    20. 1,3-Dipolar Cycloaddition: Click Chemistry for the Synthesis of 5-Substituted Tetrazoles from Organoaluminum Azides and Nitriles (pages 8440–8444)

      Valentina Aureggi and Gottfried Sedelmeier

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200701045

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      Cheap and safe: Conventional methods to prepare tetrazoles employ dangerous, toxic reagents. A new route to these heterocycles (see scheme) uses inexpensive and nontoxic dialkyl aluminum azides. The cycloaddition occurs under mild conditions and tolerates a variety of functional groups. The low cost and ecocompatibility make this process attractive for large-scale preparation.

    21. A Highly Selective Fluorescent Probe for Thiophenols (pages 8445–8448)

      Wei Jiang, Qingquan Fu, Hongyou Fan, Joe Ho and Wei Wang

      Version of Record online: 28 SEP 2007 | DOI: 10.1002/anie.200702271

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      A rapid response to thiophenols is obtained with probe 1 (see scheme), which induces a significant (>50-fold) fluorescence enhancement as a result of cleavage of the electron-withdrawing moiety, thus generating strongly fluorescent molecule 2. No fluorescence is obtained with aliphatic thiols, including cysteine and glutathione, or other nucleophiles.

    22. Interlayer Modification of a Layered Titanate with Two Kinds of Organic Functional Units for Molecule-Specific Adsorption (pages 8449–8451)

      Yusuke Ide and Makoto Ogawa

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200702360

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      Selective removal: Alkyl and phenyl groups were immobilized within an interlayer space of a layered titanate to adsorb selectively and effectively 4-nonylphenol (NPh, in light colors) from aqueous solution. The immobilization of two kinds of functional units in a confined nanospace is a useful way to tailor materials with molecular recognition abilities for a wide variety of molecules.

    23. Enzyme-Responsive Materials: Chirality to Program Polymer Reactivity (pages 8452–8454)

      Christopher J. Duxbury, Iris Hilker, Stefaan M. A. de Wildeman and Andreas Heise

      Version of Record online: 5 OCT 2007 | DOI: 10.1002/anie.200702438

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      A programmed response: Enzyme-responsive materials have been prepared from enzymatically synthesized, enantiomerically pure monomers. The extent of the material's response is encoded within its chiral makeup. This code can be effectively read out by an enzymatic process, which leads to a change in the thermal properties of the material. The picture shows esterification of chiral alcohol groups on a polymer backbone (green) with vinyl acetate (red).

    24. Intrinsic Deuterium Kinetic Isotope Effects in Glutamate Mutase Measured by an Intramolecular Competition Experiment (pages 8455–8459)

      Miri Yoon, Anastasia Kalli, Hyang-Yeol Lee, Kristina Håkansson and E. Neil G. Marsh

      Version of Record online: 1 OCT 2007 | DOI: 10.1002/anie.200702448

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      Intramolecular competition between hydrogen and deuterium atoms at the methyl group of methylaspartate was used to measure the intrinsic primary deuterium isotope effect for 5′-deoxyadenosine formation in a B12 enzyme. The value is much smaller than expected based on measurements on other B12 enzymes and model systems. This strongly suggests that glutamate mutase modulates the transition state for hydrogen transfer.

    25. Palladium-Catalyzed Aminocarbonylation of Aryl Chlorides at Atmospheric Pressure: The Dual Role of Sodium Phenoxide (pages 8460–8463)

      Joseph R. Martinelli, Thomas P. Clark, Donald A. Watson, Rachel H. Munday and Stephen L. Buchwald

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200702943

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      No pressure, no worries: A general, functional-group-tolerant, mild system for the Pd-catalyzed carbonylation of aryl chlorides to the corresponding amides has been developed. The catalyst operates at 1 atm CO using an inexpensive, air-stable, and commercially available ligand (see scheme, Cy=cyclohexyl). Sodium phenoxide is a critical additive in this transformation; its role has been studied using in situ IR spectroscopy.

    26. Oxidative Cleavage in the Construction of Complex Molecules: Synthesis of the Leucascandrolide A Macrolactone (pages 8464–8467)

      Hyung Hoon Jung, John R. Seiders II and Paul E. Floreancig

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200702999

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      Oxidation leads to macrolactone: Oxidative carbon–carbon bond activation is a key step in the formal synthesis of leucascandrolide A, which is formed in one step from 1. Additional features are stereoselective BiBr3-mediated allylation, acetal formation as a fragment-coupling reaction, and a rhenium-mediated allylic alcohol transposition leading to stable macrolactol formation.

    27. Asymmetric Activation of tropos 2,2′-Biphenol with Cinchonine Generates an Effective Catalyst for the Asymmetric Strecker Reaction of N-Tosyl-Protected Aldimines and Ketoimines (pages 8468–8470)

      Jun Wang, Xiaolei Hu, Jun Jiang, Shaohua Gou, Xiao Huang, Xiaohua Liu and Xiaoming Feng

      Version of Record online: 4 SEP 2007 | DOI: 10.1002/anie.200703188

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      Tropo' bello! Asymmetric activation of tropos biphenol 1 and Ti(OiPr)4 with cinchonine 2 generates a remarkably effective catalyst in situ for the asymmetric Strecker reaction of N-tosyl (Ts) imines under mild conditions. Various substrates including aldimines, aryl alkyl ketoimines, and unsymmetrical diaryl ketoimines were investigated, and most of them exhibited high enantioselectivities (up to 99 % ee) as well as high reactivities.

    28. Kinetic Resolution of 1,2-Diols through Highly Site- and Enantioselective Catalytic Silylation (pages 8471–8474)

      Yu Zhao, Aurpon W. Mitra, Amir H. Hoveyda and Marc L. Snapper

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200703650

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      Resolved to silylate: A chiral silylation catalyst is used for kinetic resolution of three classes of acyclic 1,2-diols. The catalyst differentiates, with excellent precision, between the two hydroxy groups of a substrate. The majority of the diols, obtained in high enantiomeric purity, cannot be accessed with similar stereochemical purity through catalytic asymmetric dihydroxylation.

    29. Chiral Symmetry Breaking by Chemically Manipulating Statistical Fluctuation in Crystallization (pages 8475–8479)

      Shu-Ting Wu, Yan-Rong Wu, Qing-Qing Kang, Hui Zhang, La-Sheng Long, Zhiping Zheng, Rong-Bin Huang and Lan-Sun Zheng

      Version of Record online: 2 OCT 2007 | DOI: 10.1002/anie.200703443

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      Breaking out: By introducing a relatively stable intermediate to chemically control the nucleation rate, chiral symmetry breaking was achieved in the crystallization of intrinsically chiral helical coordination polymers. The fewer crystal clusters formed, the more pronounced the symmetry breaking (see picture).

    30. Poly(anthrylenebutadiynylene)s: Precursor-Based Synthesis and Band-Gap Tuning (pages 8480–8483)

      Mark S. Taylor and Timothy M. Swager

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200703409

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      Skipping the monomer: A highly efficient reductive aromatization reaction transforms an unconjugated precursor polymer into a high-molecular-weight, butadiyne-linked anthracene homopolymer (see scheme). Photophysical and electrochemical analyses reveal that some of these new materials display remarkable stability in both neutral and doped states and have unusually low intrinsic band gaps.

    31. Bulky Chiral Carbene Ligands and Their Application in the Palladium-Catalyzed Asymmetric Intramolecular α-Arylation of Amides (pages 8484–8487)

      E. Peter Kündig, Thomas M. Seidel, Yi-xia Jia and Gérald Bernardinelli

      Version of Record online: 2 OCT 2007 | DOI: 10.1002/anie.200703408

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      Bring on the big cats: New, C2-symmetric bulky N-heterocyclic carbene ligands bring major improvements in the palladium-catalyzed asymmetric intramolecular α-arylation of amides to give oxindoles (see picture, dba=trans,trans-dibenzylideneacetone), which are formed in high yield and excellent enantiomeric purity.

    32. Promising Material for Infrared Nonlinear Optics: NaI3O8 Salt Containing an Octaoxotriiodate(V) Anion Formed from Condensation of [IO3] Ions (pages 8488–8491)

      Delphine Phanon and Isabelle Gautier-Luneau

      Version of Record online: 2 OCT 2007 | DOI: 10.1002/anie.200703340

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      Off-center: The material NaI3O8 is obtained as millimeter-sized single crystals (see photograph of a single crystal; crystal size: 2×2×5 mm3), and its crystal structure is acentric. It is transparent up to 12.5 μm, thus covering the three atmospheric transparency windows. It generates an intense second-harmonic-generation signal and has a high optical damage threshold.

    33. Isoenzymes of Pig-Liver Esterase Reveal Striking Differences in Enantioselectivities (pages 8492–8494)

      Anke Hummel, Elke Brüsehaber, Dominique Böttcher, Harald Trauthwein, Kai Doderer and Uwe T. Bornscheuer

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200703256

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      An esterase toolbox: A set of isoenzymes of pig liver esterases (PLE) is identified, cloned, and overexpressed in E. coli. They show striking differences in enantioselectivity and enantiopreference in the kinetic resolution of acetates of secondary alcohols as well as the desymmetrization of cis-3,5-diacetoxycyclopent-1-ene to 1 a and 1 b (see picture: enantiopreference of the new isoenzymes and a commercial PLE isoenzyme mixture).

    34. Intracellular Magnetite Biomineralization in Bacteria Proceeds by a Distinct Pathway Involving Membrane-Bound Ferritin and an Iron(II) Species (pages 8495–8499)

      Damien Faivre, Lars H. Böttger, Berthold F. Matzanke and Dirk Schüler

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200700927

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      A time-resolved study of magnetite formation in magnetotactic bacteria has shown that magnetite biomineralization proceeds first by coprecipitation of Fe2+ and Fe3+ ions and then via small magnetite crystallites (see picture) within invaginating magnetosomes associated with the cell membrane, which further develop into mature crystals after magnetosome vesicles are released from the cell membrane.

    35. Cobalt-Catalyzed Alder–Ene Reaction (pages 8500–8502)

      Gerhard Hilt and Jonas Treutwein

      Version of Record online: 26 SEP 2007 | DOI: 10.1002/anie.200703180

      Thumbnail image of graphical abstract

      Next reactant, new pathway: An inexpensive cobalt–diphosphine complex is able to catalyze the intermolecular Alder–ene reaction of internal alkynes with terminal alkenes. The products are functionalized 1,4-dienes (see scheme) which are obtained in good yields and with excellent chemo-, regio-, and stereoselectivities.

    36. Boron Cluster Cations: Transition from Planar to Cylindrical Structures (pages 8503–8506)

      Esther Oger, Nathan R. M. Crawford, Rebecca Kelting, Patrick Weis, Manfred M. Kappes and Reinhart Ahlrichs

      Version of Record online: 1 OCT 2007 | DOI: 10.1002/anie.200701915

      Thumbnail image of graphical abstract

      Above a certain size, boron clusters prefer a cylindrical arrangement over a planar one. Experimental determination of the collision cross section combined with density functional calculations showed that the transition to cylindrical structures takes place at B16+ for boron clusters. The picture shows some of the investigated structures. The left column represents the global minima; the other columns show less favorable structures.

    37. Regioselective 1-Hexene Oligomerization Using Cationic Bis(phenolato) Group 4 Metal Catalysts: Switch from 1,2- to 2,1-Insertion (pages 8507–8510)

      Bing Lian, Klaus Beckerle, Thomas P. Spaniol and Jun Okuda

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200703218

      Thumbnail image of graphical abstract

      A cat of two tales: Cationic Group 4 metal catalysts that contain a linked bis(phenolato) ligand efficiently catalyze the oligomerization of 1-hexene. Whereas oligo(1-hexene)s arising from 2,1-insertion of 1-hexene are observed for the titanium complexes, those prepared using zirconium and hafnium complexes are formed by 1,2-insertion.

    38. Thermodynamic Inhibition Profile of a Cyclopentyl and a Cyclohexyl Derivative towards Thrombin: The Same but for Different Reasons (pages 8511–8514)

      Christof Gerlach, Michael Smolinski, Holger Steuber, Christoph A. Sotriffer, Andreas Heine, David G. Hangauer and Gerhard Klebe

      Version of Record online: 27 SEP 2007 | DOI: 10.1002/anie.200701169

      Thumbnail image of graphical abstract

      Small changes, big effects: Two thrombin inhibitors (see picture; R=cyclopentyl (1 a), R=cyclohexyl (1 b)) were characterized thermodynamically and computationally to explain their identical binding constants. Surprisingly, the free energy of binding is achieved with different enthalpic and entropic contributions (see plot).

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