Angewandte Chemie International Edition

Cover image for Vol. 48 Issue 35

August 17, 2009

Volume 48, Issue 35

Pages 6363–6561

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Review
    7. Highlights
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Cover Picture: A Soluble and Highly Conductive Ionomer for High-Performance Hydroxide Exchange Membrane Fuel Cells (Angew. Chem. Int. Ed. 35/2009) (page 6363)

      Shuang Gu, Rui Cai, Ting Luo, Zhongwei Chen, Minwei Sun, Yan Liu, Gaohong He and Yushan Yan

      Article first published online: 12 AUG 2009 | DOI: 10.1002/anie.200990181

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      A hydroxide-conducting and stable ionomer is required to maximize the performance of hydroxide-exchange membrane fuel cells (HEMFCs). In their Communication on page 6499 ff. Y. S. Yan et al. report the synthesis of such an ionomer—a polysulfone–methylene phosphonium hydroxide—as well as its method of action which is based on creating a three-phase boundary in the catalyst layer.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Review
    7. Highlights
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Inside Cover: Biotransformation on Polymer–Peptide Conjugates: A Versatile Tool to Trigger Microstructure Formation (Angew. Chem. Int. Ed. 35/2009) (page 6364)

      Hans Kühnle and Hans G. Börner

      Article first published online: 12 AUG 2009 | DOI: 10.1002/anie.200990182

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      The BioSwitch Concept uses posttranslational modification to control the formation of hierarchical microstructures. As described by H. Kühnle and H. G. Börner in their Communication on page 6431 ff, the incorporation of phosphorylated threonine residues into the peptide segment of a polymer–peptide conjugate effectively suppresses the self-assembly of the bioconjugate. The acid phosphatase cleaves the phosphate groups from the peptide segment, activates the peptide function of the β-sheet aggregation domain, and triggers the self-assembly process.

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Review
    7. Highlights
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Graphical Abstract: Angew. Chem. Int. Ed. 35/2009 (pages 6367–6377)

      Article first published online: 12 AUG 2009 | DOI: 10.1002/anie.200990183

  4. News

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

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Review
    7. Highlights
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Cathedrals of Science.The Personalities and Rivalries that Made Modern Chemistry. By Patrick Coffey. (pages 6384–6385)

      Anthony S. Travis

      Article first published online: 12 AUG 2009 | DOI: 10.1002/anie.200903223

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      Oxford University Press, Oxford 2008. 379 pp., hardcover $ 29.95.—ISBN 978-0195321340

  6. Highlights

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

      Radicals and Transition-Metal Catalysis: An Alliance Par Excellence to Increase Reactivity and Selectivity in Organic Chemistry (pages 6386–6389)

      Leigh Ford and Ullrich Jahn

      Article first published online: 24 JUN 2009 | DOI: 10.1002/anie.200901761

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      Welcome to radical catalysis: Radicals are “tamed” in transition-metal complexes which serve as catalysts for a number of reactions—Kumada couplings (see scheme), highly regioselective cobalt-catalyzed eliminations, Markovnikov additions, and reductive epoxide openings catalyzed by a titanium/rhodium system. All of these reactions are powered by the high reactivity of radical intermediates in the catalytic cycle of the metal-catalyzed process.

    2. Divergent Reactions

      Transition-Metal-Catalyzed Ring Opening of Hetero-Diels–Alder Adducts (pages 6390–6393)

      Gerhard Hilt

      Article first published online: 29 JUN 2009 | DOI: 10.1002/anie.200901939

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      Either–or: Exciting developments have been made in the field of transition-metal-catalyzed ring-opening reactions of bicyclic, heteroatom-containing Diels–Alder adducts. These regio- und stereodivergent reactions open interesting new alternatives to conventional methods (see scheme, cod=1,5-cyclooctadiene).

    3. Drug Discovery in Insects

      Insects: True Pioneers in Anti-Infective Therapy and What We Can Learn from Them (pages 6394–6396)

      Helge B. Bode

      Article first published online: 30 JUN 2009 | DOI: 10.1002/anie.200902152

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      Candicidin D is a potent natural product that was recently re-isolated from bacterial insect symbionts. Some insects cultivate the producing bacteria in specialized organs in order to fight pathogens. Besides the identification of new natural products for human use, these findings have also implications for our understanding of resistance development and drug discovery strategies in general.

  7. Minireview

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

      The Challenge of Atropisomerism in Drug Discovery (pages 6398–6401)

      Jonathan Clayden, Wesley J. Moran, Paul J. Edwards and Steven R. LaPlante

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200901719

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      A twist in the tale: Recent reports have highlighted solutions to the problems encountered when drug candidates exist as slowly interconverting conformers or atropisomers (see scheme). This Minireview brings together the various strategies that have been adopted and proposes a general approach to handling an aspect of stereochemistry which has received little attention from drug regulatory agencies.

  8. Review

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

      Jahn–Teller Effects in Molecular Cations Studied by Photoelectron Spectroscopy and Group Theory (pages 6404–6424)

      Hans Jakob Wörner and Frédéric Merkt

      Article first published online: 10 AUG 2009 | DOI: 10.1002/anie.200900526

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      More than distortion: The Jahn–Teller effect in molecules is more complex than a simple geometric distortion. It significantly alters the electronic and geometric structure, and can result in unexpected isomerism and chirality, for example in deuterated isotopologues of CH4+ (see picture). Rotationally resolved photoelectron spectroscopy and group theory provide precise information about the dynamic structure of Jahn–Teller distorted molecules.

  9. Communications

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

      Bismuth-Catalyzed Growth of SnS2 Nanotubes and Their Stability (pages 6426–6430)

      Aswani Yella, Enrico Mugnaioli, Martin Panthöfer, Helen Annal Therese, Ute Kolb and Wolfgang Tremel

      Article first published online: 9 JUN 2009 | DOI: 10.1002/anie.200900546

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      Nanotubes of tin disulfide were fabricated from SnS2 nanoflakes by the vapor–liquid–solid process using bismuth nanodroplets as a catalyst. The SnS2 reagent in the gas phase preferentially adsorbs onto the bismuth particles; upon cooling, nucleation and growth of SnS2 nanotubes occurs (see HRTEM image). Annealing the nanotubes results in the formation of SnS2/SnS superlattices.

    2. Polymer-Peptide Conjugates

      Biotransformation on Polymer–Peptide Conjugates: A Versatile Tool to Trigger Microstructure Formation (pages 6431–6434)

      Hans Kühnle and Hans G. Börner

      Article first published online: 8 JUL 2009 | DOI: 10.1002/anie.200805768

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      At the flick of a switch: Introducing phosphate moieties into (Thr-Val)X peptide aggregation domains disturbs the formation of secondary structures. This suppression is used to regulate the self-assembly of polymer–peptide conjugates. A phosphatase enzyme which hydrolyzes the phosphate esters then triggers the self-assembly process generating fibrillar aggregates (see scheme).

    3. Zintl Anions

      [Zn6Sn3Bi8]4−: Expanding the Intermetalloid Zintl Anion Concept to Ternary Systems (pages 6435–6438)

      Felicitas Lips and Stefanie Dehnen

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200902249

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      Zintl to the third: [Zn§Zn5Sn3Bi3§Bi5]4− (see structure), the first ternary intermetalloid Zintl anion, was obtained upon reaction of the binary anion [Sn2Bi2]2− with ZnPh2 in 1,2-diaminoethane/[2.2.2]crypt solution. X-ray structure analysis and DFT calculations indicate varied bonding within the intermetalloid cage and rationalize the impact of the ternary composition on structural and electronic properties.

    4. Interfaces

      Different Molecules Experience Different Polarities at the Air/Water Interface (pages 6439–6442)

      Sobhan Sen, Shoichi Yamaguchi and Tahei Tahara

      Article first published online: 7 AUG 2009 | DOI: 10.1002/anie.200901094

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      Split the difference: Interface-selective nonlinear spectroscopy disclosed that five coumarin derivatives exhibit significantly different solvachromatic shifts at the air/water interface, revealing that structurally different molecules experience notably different local effective polarities (equation image), even at the same water interface (see picture; arrows indicate transition dipole moments).

    5. Peptide Rotaxanes

      Rotaxane-Based Propeptides: Protection and Enzymatic Release of a Bioactive Pentapeptide (pages 6443–6447)

      Anthony Fernandes, Aurélien Viterisi, Frédéric Coutrot, Stéphanie Potok, David A. Leigh, Vincent Aucagne and Sébastien Papot

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200903215

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      Ring of protection: A [2]rotaxane 1 protects and selectively releases a bioactive pentapeptide. The rotaxane macrocycle provides a defensive shield that very significantly improves the poor stability of the peptide to both individual peptidases and the cocktail of enzymes present in human plasma. Glycosidase-catalyzed cleavage of a carbohydrate ‘stopper’ in the rotaxane triggers release of the parent peptide (see picture).

    6. Antitumor Agents

      Sulindac Inhibits Canonical Wnt Signaling by Blocking the PDZ Domain of the Protein Dishevelled (pages 6448–6452)

      Ho-Jin Lee, Nick X. Wang, De-Li Shi and Jie J. Zheng

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200902981

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      A new application: The nonsteroidal anti-inflammatory drug sulindac interacts directly and specifically with the PDZ domain of the protein Dishevelled (Dvl), which is a key intracellular component of the Wnt signaling pathways. Sulindac binds to the conventional peptide-binding pocket of the domain (see picture), and may exert a cancer chemoprotective effect by blocking it, thereby inhibiting canonical Wnt signaling.

    7. Metallacycles

      Annulation of Metallabenzenes: From Osmabenzene to Osmabenzothiazole to Osmabenzoxazole (pages 6453–6456)

      Tongdao Wang, Shunhua Li, Hong Zhang, Ran Lin, Feifei Han, Yumei Lin, Ting Bin Wen and Haiping Xia

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200902738

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      Fused metallaaromatics have been conveniently prepared from metallabenzenes (see scheme). The intramolecular SNAr reaction of an osmabenzene allowed the first examples of a metallabenzothiazole and a metallabenzoxazole to be isolated.

    8. H2 Activation

      The Crystal Structure of an [Fe]-Hydrogenase–Substrate Complex Reveals the Framework for H2 Activation (pages 6457–6460)

      Takeshi Hiromoto, Eberhard Warkentin, Johanna Moll, Ulrich Ermler and Seigo Shima

      Article first published online: 21 JUL 2009 | DOI: 10.1002/anie.200902695

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      An open and closed case: The structure of a binary complex of C176A [Fe]-hydrogenase with methylenetetrahydromethanopterin was solved at 2.15 Å resolution in an open conformation. A closed form of the complex was modeled on the basis of the experimentally determined structure. In this model, the iron-site trans to the acyl carbon is located next to the C14a and therefore considered as H2 binding site.

    9. Artificial Photosynthesis

      Topologically Matching Supramolecular n/p-Heterojunction Architectures (pages 6461–6464)

      Rajesh Bhosale, Alejandro Perez-Velasco, Velayutham Ravikumar, Ravuri S. K. Kishore, Oksana Kel, Alberto Gomez-Casado, Pascal Jonkheijm, Jurriaan Huskens, Plinio Maroni, Michal Borkovec, Tomohisa Sawada, Eric Vauthey, Naomi Sakai and Stefan Matile

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200902551

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      Matching matters when building supramolecular n/p-heterojunction photosystems on solid supports that excel with efficient photocurrent generation, important critical thickness, smooth surfaces, and flawless responsiveness to functional probes for the existence of operational intra- and interlayer recognition motifs.

    10. Glycome Analysis

      A Simple Electrochemical Cytosensor Array for Dynamic Analysis of Carcinoma Cell Surface Glycans (pages 6465–6468)

      Wei Cheng, Lin Ding, Shijia Ding, Yibing Yin and Huangxian Ju

      Article first published online: 7 JUL 2009 | DOI: 10.1002/anie.200902356

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      Sugar and spice: The title method for the simultaneous multiplex analysis of intact cell-surface glycans (see picture) shows excellent performance in sensitivity, stability, and practicality. The strategy can be used to analyze the dynamic variation of the cell-surface glycome and to decipher cellular pathophysiological processes.

    11. Bond Theory

      Hypervalent Carbon Atom: “Freezing” the SN2 Transition State (pages 6469–6471)

      Simon C. A. H. Pierrefixe, Sebastiaan J. M. van Stralen, Joost N. P. van Stralen, Célia Fonseca Guerra and F. Matthias Bickelhaupt

      Article first published online: 21 JUL 2009 | DOI: 10.1002/anie.200902125

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      High Five! Under certain circumstances a carbon atom can become hypervalent (see structure) and bind five substituents in the trigonal-bipyramidal structure, which is normally the labile SN2 transition state.

    12. Core–Shell Particles

      Spatially Resolved Catalysis for Controlling the Morphology of Polymer Particles (pages 6472–6475)

      Till Diesing, Giovanni Rojas, Markus Klapper, Gerhard Fink and Klaus Müllen

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200902047

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      Two in one: A replication effect allows the formation of core–shell particles in a single olefin polymerization step, which occurs through the simultaneous use of spatially resolved metallocene catalysts immobilized on a hybrid inorganic–organic support (see picture). Catalyst A was exclusively supported in the inorganic core, while catalyst B was immobilized in the organic shell.

    13. Lanthanides

      A Miniaturized Linear pH Sensor Based on a Highly Photoluminescent Self-Assembled Europium(III) Metal–Organic Framework (pages 6476–6479)

      Bogdan V. Harbuzaru, Avelino Corma, Fernando Rey, Jose L. Jordá, Duarte Ananias, Luis D. Carlos and João Rocha

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200902045

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      Small but important: A miniaturized prototype for pH sensing in the pH range 5–7.5 has been constructed from a photoluminescent Eu3+ metal–organic framework that contains two different Eu3+ sites (Eu1 and Eu2; see picture) and self-assembles through hydrogen bonding and π–π interactions. This material has a very high quantum yield and an excellent balance between absorption, energy transfer, and emission rate.

    14. Fluorescent Probes

      Exciton-Controlled Hybridization-Sensitive Fluorescent Probes: Multicolor Detection of Nucleic Acids (pages 6480–6484)

      Shuji Ikeda, Takeshi Kubota, Mizue Yuki and Akimitsu Okamoto

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200902000

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      A colorful bunch: A series of fluorescent probes designed on the basis of fluorescence quenching caused by an excitonic interaction contain different dye moieties and fluoresce in various colors upon hybridization with their target nucleic acid. The picture shows simultaneous fluorescence in three colors in the nucleus of a cell containing an excess of three different microRNA strands. Left: differential interference contrast image.

    15. Nanotechnology

      Encapsulation of Sn@carbon Nanoparticles in Bamboo-like Hollow Carbon Nanofibers as an Anode Material in Lithium-Based Batteries (pages 6485–6489)

      Yan Yu, Lin Gu, Chunlei Wang, Abirami Dhanabalan, Peter A. van Aken and Joachim Maier

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200901723

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      Carbon-coated Sn nanoparticles in carbon nanofibers (see image) were fabricated by pyrolysis of coaxially electrospun nanofibers as an anode material for Li-ion batteries. The significantly improved electrochemical performance of such an electrode is believed to result from the unique nanostructure consisting of a thin carbon shell around tin nanoparticles, which are further encapsulated in hollow carbon nanofibers.

    16. POM-Based Nanocomposites

      Supramolecular Silver Polyoxometalate Architectures Direct the Growth of Composite Semiconducting Nanostructures (pages 6490–6493)

      Carsten Streb, Ryo Tsunashima, Donald A. MacLaren, Thomas McGlone, Tomoyuki Akutagawa, Takayoshi Nakamura, Antonino Scandurra, Bruno Pignataro, Nikolaj Gadegaard and Leroy Cronin

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200901650

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      Nanosilver on a string: Crystalline silver polyoxovanadate supramolecular architectures are employed as precursors for the synthesis of composite nanowires (see scheme). The nanostructures are composed of semiconducting vanadium oxide which forms wires with high aspect ratios, and are embedded with metallic silver nanoparticles.

    17. Drug Delivery

      Reversible Cell-Specific Drug Delivery with Aptamer-Functionalized Liposomes (pages 6494–6498)

      Zehui Cao, Rong Tong, Abhijit Mishra, Weichen Xu, Gerard C. L. Wong, Jianjun Cheng and Yi Lu

      Article first published online: 21 JUL 2009 | DOI: 10.1002/anie.200901452

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      Aptamer advantages: Cell-specific delivery of the anticancer drug cisplatin through a nucleolin-aptamer-conjugated, cisplatin-encapsulating liposome delivery system is described. Calcein was incorporated into the target MCF-7 cells (see top image) but not into LNCaP cells (see bottom image). More importantly, the extent of delivery can be controlled by using a complementary DNA of the aptamer as an antidote.

    18. Ionomers

      A Soluble and Highly Conductive Ionomer for High-Performance Hydroxide Exchange Membrane Fuel Cells (pages 6499–6502)

      Shuang Gu, Rui Cai, Ting Luo, Zhongwei Chen, Minwei Sun, Yan Liu, Gaohong He and Yushan Yan

      Article first published online: 8 MAY 2009 | DOI: 10.1002/anie.200806299

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      Easy cell: The new polymeric ionomer TPQPOH with a tris(2,4,6-trimethoxyphenyl)phosphonium unit has excellent solubility in some low-boiling-point water-soluble solvents, high ionic conductivity, and outstanding alkaline stability. A hydroxide exchange membrane fuel cell containing this ionomer exhibits increased peak power density and reduced internal resistance.

    19. Asymmetric Catalysis

      An Asymmetric Catalytic Darzens Reaction between Diazoacetamides and Aldehydes Generates cis-Glycidic Amides with High Enantiomeric Purity (pages 6503–6506)

      Wei-Jun Liu, Bing-Da Lv and Liu-Zhu Gong

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200903061

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      Titanium strength: The title reaction was catalyzed by a chiral titanium complex formed in situ from commercially available Ti(OiPr)4 and (R)-binol, and gave cis-glycidic amides with excellent enantiomeric purity (see scheme). This new method has been applied to the preparation of chiral building blocks used for the synthesis of the side chain of taxol and (−)-bestatin.

    20. Total Synthesis

      Synthesis of (−)-Hygromycin A: Application of Mitsunobu Glycosylation and Tethered Aminohydroxylation (pages 6507–6510)

      Timothy J. Donohoe, Aida Flores, Carole J. R. Bataille and Fátima Churruca

      Article first published online: 31 JUL 2009 | DOI: 10.1002/anie.200902840

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      Key points in the synthesis of (−)-hygromycin A are the tethered aminohydroxylation reaction used to prepare the aminocyclitol unit and the choice of a bulky protecting group on the sugar unit to facilitate selective Mitsunobu glycosylation and also bestow kinetic stability upon an otherwise vulnerable proton.

    21. C[BOND]H Alkenylation

      Palladium(II)-Catalyzed Regioselective Direct C2 Alkenylation of Indoles and Pyrroles Assisted by the N-(2-Pyridyl)sulfonyl Protecting Group (pages 6511–6515)

      Alfonso García-Rubia, Ramón Gómez Arrayás and Juan C. Carretero

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200902802

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      Easy on, easy off: The N-(2-pyridyl)sulfonyl group controls the direct PdII-catalyzed alkenylation of indoles, affording the corresponding products in good yields and with complete regiocontrol at C2 (see scheme, DMA=dimethylacetamide). The protocol was also extended to pyrrole derivatives. The final reductive desulfonylation affords the C2-substituted indoles and pyrroles in good yields.

    22. Liquid Crystals

      All-Organic Discotic Radical with a Spin-Carrying Rigid-Core Showing Intracolumnar Interactions and Multifunctional Properties (pages 6516–6519)

      Sonia Castellanos, Francisco López-Calahorra, Enric Brillas, Luis Juliá and Dolores Velasco

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200902641

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      The discotic liquid crystal radical 1, which is very stable in the solid state or solution, has an enantiotropic ordered hexagonal columnar mesophase above room temperature with magnetic interactions among molecular spins. Radical 1 shows electrochemical amphotericity and absorption and light-emission properties that cover the red region of the visible spectrum.

    23. Tandem Reactions

      A Base-Promoted Tandem Reaction of 3-(1-Alkynyl)chromones with 1,3-Dicarbonyl Compounds: An Efficient Approach to Functional Xanthones (pages 6520–6523)

      Lizhi Zhao, Fuchun Xie, Gang Cheng and Youhong Hu

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200902618

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      No need for a transition-metal catalyst is characteristic for the tandem process presented herein to obtain functionalized xanthones. The sequence involves multiple reactions, such as Michael addition-elimination/cyclization/1,2-addition/elimination reactions (see scheme).

    24. Asymmetric Catalysis

      pH-Regulated Asymmetric Transfer Hydrogenation of Quinolines in Water (pages 6524–6528)

      Chao Wang, Chaoqun Li, Xiaofeng Wu, Alan Pettman and Jianliang Xiao

      Article first published online: 21 JUL 2009 | DOI: 10.1002/anie.200902570

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      In buffered water, a broad range of quinoline derivatives underwent asymmetric transfer hydrogenation in air with the rhodium catalyst 1 and sodium formate as the hydrogen source to furnish synthetically important 1,2,3,4-tetrahydroquinolines with excellent enantioselectivities (see scheme; R=H, Me, F, Cl, Br, OMe; R′=alkyl, aryl).

    25. Biomass Conversion

      Catalytic Conversion of Biomass-Derived Carbohydrates into γ-Valerolactone without Using an External H2 Supply (pages 6529–6532)

      Li Deng, Jiang Li, Da-Ming Lai, Yao Fu and Qing-Xiang Guo

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200902281

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      Simplified procedure: A new catalytic route was developed for the conversion of biomass carbohydrates into γ-valerolactone (GVL) without using an external H2 supply. A model experiment with glucose provided γ-valerolactone in 48 % yield. An interesting positive effect of CO2 on the Ru-catalyzed hydrogenation was also observed. py=pyridine.

    26. Microfabrication

      Microfluidic Formation of Monodisperse, Cell-Sized, and Unilamellar Vesicles (pages 6533–6537)

      Sadao Ota, Satoko Yoshizawa and Shoji Takeuchi

      Article first published online: 30 JUL 2009 | DOI: 10.1002/anie.200902182

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      Gently down the stream: A microfluidic technique uses a continuous fluid stream to generate monodisperse unilamellar phospholipid vesicles from a single bilayer (see picture). Since the vesicles are robust and efficiently encapsulate high concentrations of various molecules, they are useful as delivery vehicles and as model cellular systems.

    27. Polyoxometalates

      Counterion Distribution around Hydrophilic Molecular Macroanions: The Source of the Attractive Force in Self-Assembly (pages 6538–6542)

      Joseph M. Pigga, Melissa L. Kistler, Chwen-Yang Shew, Mark R. Antonio and Tianbo Liu

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200902050

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      Growing blackberries: The association of counterions around {Mo72V30} polyoxometalate macroanions increases with increasing macroion concentration and decreasing solvent polarity. The counterion distribution extends about 2–9 Å from the macroion surface with the highest probability at 2–3 Å from the macroion surface. A close connection between counterion association and the self-assembly of {Mo72V30} into “blackberry” structures is observed.

    28. Functionalized Nanotubes

      Defect-Mediated Functionalization of Carbon Nanotubes as a Route to Design Single-Site Basic Heterogeneous Catalysts for Biomass Conversion (pages 6543–6546)

      Jean-Philippe Tessonnier, Alberto Villa, Olivier Majoulet, Dang Sheng Su and Robert Schlögl

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200901658

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      Graft it! Target active sites were directly grafted onto structural defects of carbon nanotubes (see picture) by electrophilic attack. This synthetic route is faster and more efficient than other approaches, and it allows a single-site design of carbon nanotube-based heterogeneous catalysts. The potential of such catalysts is tremendous for liquid-phase biomass conversion reactions.

    29. MRI Agents

      Multimodal Magnetic-Resonance/Optical-Imaging Contrast Agent Sensitive to NADH (pages 6547–6551)

      Chuqiao Tu, Ryan Nagao and Angelique Y. Louie

      Article first published online: 23 JUL 2009 | DOI: 10.1002/anie.200900984

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      Agents get smart: A macrocycle-based gadolinium complex undergoes an isomerization in the presence of NADH, leading to an r1 relaxivity increase of 54 %, while the intense fluorescence disappears (see scheme). This agent could facilitate the use of magnetic resonance imaging (MRI) for probing tissue redox status.

    30. Ethylene Polymerization

      Isolation of a Self-Activating Ethylene Trimerization Catalyst (pages 6552–6556)

      Indu Vidyaratne, Grigory B. Nikiforov, Serge I. Gorelsky, Sandro Gambarotta, Robbert Duchateau and Ilia Korobkov

      Article first published online: 27 JUL 2009 | DOI: 10.1002/anie.200900957

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      Self-help groups: The aluminatopyrrolyl complexes [{η5-2,3,4,5-Me4C4N(AlClMe2)}2Cr] and [{η5-2,3,4,5-Me4C4N(AlClMe2)CrMe(μ-NPh)2AlMe2}{Me3Al(thf)}] self-activate to give single-site ethylene polymerization catalysts. The closely related dinuclear chromium(II) complex [{η5-2,3,4,5-Me4C4N(AlClMe2)Cr}2(μ-Me)2] (see picture) is a highly active self-activating ethylene trimerization catalyst.

  10. Preview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
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      Preview: Angew. Chem. Int. Ed. 36/2009 (page 6561)

      Article first published online: 12 AUG 2009 | DOI: 10.1002/anie.200990185

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