Angewandte Chemie International Edition

Cover image for Vol. 52 Issue 42

October 11, 2013

Volume 52, Issue 42

Pages 10911–11171

  1. Cover Pictures

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. You have free access to this content
      Cover Picture: On the Way Towards Greener Transition-Metal-Catalyzed Processes as Quantified by E Factors (Angew. Chem. Int. Ed. 42/2013) (page 10911)

      Dr. Bruce H. Lipshutz, Nicholas A. Isley, James C. Fennewald and Eric D. Slack

      Article first published online: 25 SEP 2013 | DOI: 10.1002/anie.201308153

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      As E Factors drop it's a win-win for chemistry and the environment. In their Minireview on page 10952 ff., B. H. Lipshutz and co-workers document, by direct comparisons with transition-metal-catalyzed cross-coupling reactions from pharma, just how low they can go using a commercially available designer surfactant in water as the reaction medium. As the organic solvent usage drops, E Factors can plummet by as much as an order of magnitude. Let's get organic solvents out of organic reactions, and increase sustainability.

    2. You have free access to this content
      Inside Cover: The Catalytically Active Copper-Amyloid-Beta State: Coordination Site Responsible for Reactive Oxygen Species Production (Angew. Chem. Int. Ed. 42/2013) (page 10912)

      Laure-Estelle Cassagnes, Vincent Hervé, Prof.Dr. Françoise Nepveu, Dr. Christelle Hureau, Prof.Dr. Peter Faller and Dr. Fabrice Collin

      Article first published online: 4 SEP 2013 | DOI: 10.1002/anie.201307308

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      In Alzheimer's disease, the redox-active copper center bound to the amyloid-beta peptide is able to produce reactive oxygen species by way of a low-populated redox-competent state. Insights into the coordination sphere of this state are reported by P. Faller, F. Collin, and co-workers in their Communication on page 11110 ff. The copper atom is bound by the N-terminal aspartate and the histidine dyad, while the third histidine acts as a gate keeper.

    3. You have free access to this content
      Inside Back Cover: A Co-catalyst-Loaded Ta3N5 Photoanode with a High Solar Photocurrent for Water Splitting upon Facile Removal of the Surface Layer (Angew. Chem. Int. Ed. 42/2013) (page 11173)

      Mingxue Li, Dr. Wenjun Luo, Dapeng Cao, Xin Zhao, Prof. Zhaosheng Li, Prof. Tao Yu and Prof. Zhigang Zou

      Article first published online: 2 SEP 2013 | DOI: 10.1002/anie.201307185

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      The highest solar photocurrent among all currently available tantalum nitride (Ta3N5) photoanodes is obtained by oxidation and nitridation of tantalum foils, as described by W. Luo, Z. Zou et al. in their Communication on page 11016 ff. The high photocurrent mainly originates from the facile thermal or mechanical exfoliation of surface recombination centers.

    4. You have free access to this content
      Back Cover: Arimetamycin A: Improving Clinically Relevant Families of Natural Products through Sequence-Guided Screening of Soil Metagenomes (Angew. Chem. Int. Ed. 42/2013) (page 11174)

      Dr. Hahk-Soo Kang and Prof. Sean F. Brady

      Article first published online: 2 SEP 2013 | DOI: 10.1002/anie.201307204

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      Watch your step, there is new chemistry everywhere In their Communication on page 11063 ff., S. F. Brady and H.-S. Kang describe a potent new anthracycline discovered by soil-DNA mining methods. DNA extracted from Sonoran Desert soil (USA) was screened for gene clusters predicted to produce new natural products. The soil-DNA-derived arm cluster encodes arimetamycin A, an anthracycline that is active against multidrug-resistant cancer cells and more potent than natural anthracyclines currently used in cancer therapy.

  2. Editorial

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. You have free access to this content
  3. Graphical Abstract

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
  4. News

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
  5. Author Profile

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. Sir John Meurig Thomas (pages 10938–10940)

      Article first published online: 31 MAY 2013 | DOI: 10.1002/anie.201303486

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      “My greatest achievement has been to combine being a teacher, a researcher, and a popularizer of science for over 50 years. My worst nightmare is to find myself dumbstruck when I am about to give a lecture …” This and more about Sir John Meurig Thomas can be found on page 10938.

  6. News

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
  7. Book Review

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. One-Dimensional Nanostructures. Principles and Applications. Edited by Tianyou Zhai and Jiannian Yao. (pages 10942–10943)

      Lifeng Chi

      Article first published online: 14 AUG 2013 | DOI: 10.1002/anie.201305485

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      John Wiley and Sons, Hoboken, 2012. 576 pp., hardcover, € 129.00.—ISBN 978-1118071915

  8. Highlights

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. Antioxidants

      One Size Does Not Fit All—Bacterial Cell Death by Antibiotics Cannot Be Explained by the Action of Reactive Oxygen Species (pages 10946–10948)

      Prof. Dr. Nikolai Kuhnert

      Article first published online: 3 SEP 2013 | DOI: 10.1002/anie.201304548

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      Back to square one: Two recent studies prove that reactive oxygen species (ROS) are not responsible for bacterial cell death after treatment with antibiotics. The ROS concept cannot be generalized to explain all processes resulting in cell death. The search for the mechanism of action of bacterial antibiotics must thus return to the beginning.

    2. Fluorescence Microscopy

      Tissue Clearing for Optical Anatomy (pages 10949–10951)

      Dr. Dmytro A. Yushchenko and Priv.-Doz. Dr. Carsten Schultz

      Article first published online: 3 SEP 2013 | DOI: 10.1002/anie.201306039

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      Quest for transparency: Detailed optical imaging of complex biological entities remains an unmet goal mainly because of the light scattering of biological tissue. A new approach to tissue clearing termed CLARITY is getting us closer to an anatomical view of thick tissues and entire organs with cellular resolution.

  9. Minireview

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. Green Chemistry

      On the Way Towards Greener Transition-Metal-Catalyzed Processes as Quantified by E Factors (pages 10952–10958)

      Dr. Bruce H. Lipshutz, Nicholas A. Isley, James C. Fennewald and Eric D. Slack

      Article first published online: 12 SEP 2013 | DOI: 10.1002/anie.201302020

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      En vogue: Consider greening up palladium-catalyzed reactions by using a minimum amount of water as the only reaction medium, enabled by designer surfactants. Direct comparisons with several commonly used reactions in the pharmaceutical industry illustrate the potential to reduce the dependence on organic solvents, and thereby drive organic waste and, hence, E Factors down and economic benefits up.

  10. Review

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. Natural Products

      The Psymberin Story—Biological Properties and Approaches towards Total and Analogue Syntheses (pages 10960–10985)

      Dr. Max Bielitza and Prof. Dr. Jörg Pietruszka

      Article first published online: 17 SEP 2013 | DOI: 10.1002/anie.201301259

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      After its isolation from different sponges, the cytotoxic compound psymberin has drawn enormous attention in terms of its structure elucidation and (bio)synthesis because of its fascinating architecture and impressive biological properties. This endeavor resulted in an array of new synthetic strategies that also led to more potent analogues by altering different structural motifs.

  11. Communications

    1. Top of page
    2. Cover Pictures
    3. Editorial
    4. Graphical Abstract
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    1. Mesoporous Materials

      Surface-Metastable Phase-Initiated Seeding and Ostwald Ripening: A Facile Fluorine-Free Process towards Spherical Fluffy Core/Shell, Yolk/Shell, and Hollow Anatase Nanostructures (pages 10986–10991)

      Lu Cao, Dr. Dehong Chen and Prof. Rachel A. Caruso

      Article first published online: 23 AUG 2013 | DOI: 10.1002/anie.201305819

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      Versatile synthetic method: Monodisperse anatase microspheres with various complex morphologies have been synthesized by using a versatile fluorine-free solvothermal process in the presence of ammonia. Unambiguous evidence related to surface seeding and a subsequent hollowing process revealed an Ostwald ripening evolution process.

    2. Cascade Reactions

      Copper-Catalyzed Domino Cycloaddition/C[BOND]N Coupling/Cyclization/(C[BOND]H Arylation): An Efficient Three-Component Synthesis of Nitrogen Polyheterocycles (pages 10992–10996)

      Dr. Wenyuan Qian, Hao Wang and Dr. Jennifer Allen

      Article first published online: 6 SEP 2013 | DOI: 10.1002/anie.201305970

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      A cat of all trades: A single copper catalyst promoted up to three reaction steps with separate catalytic cycles in a domino sequence (azide–alkyne cycloaddition/Goldberg amidation/Camps cyclization/(C[BOND]H arylation)) for the rapid construction of complex heterocycles from three simple components under mild conditions (see scheme). Facile cleavage of the triazole ring enables further elaboration of the condensation products.

    3. Bone Repair

      Bone-Crack Detection, Targeting, and Repair Using Ion Gradients (pages 10997–11001)

      Vinita Yadav, Jonathan D. Freedman, Prof. Mark Grinstaff and Prof. Ayusman Sen

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201305759

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      Bone cracks can be detected by utilizing the damaged matrix itself as both the trigger and the fuel. A crack in a material with a high mineral content such as bone generates ion gradients, which can be utilized for active targeting and treatment. This approach to targeting a biological structure augments current methods, which are focused on biomacromolecular interactions involving proteins and nucleic acids.

    4. Energetic Materials

      [BH3C(NO2)3]: The First Room-Temperature Stable (Trinitromethyl)borate (pages 11002–11006)

      Guillaume Bélanger-Chabot, Dr. Martin Rahm, Prof. Ralf Haiges and Prof. Karl O. Christe

      Article first published online: 27 AUG 2013 | DOI: 10.1002/anie.201305602

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      The marriage of fire and water: The strongly oxidizing trinitromethyl and strongly reducing BH3 groups were successfully combined for the first time in the novel [BH3C(NO2)3] ion. The stability at room temperature of the new (trinitromethyl)borate is in sharp contrast to the behavior of [BCl3C(NO2)3], which already decomposes at −20 °C.

    5. Scanning Tunneling Spectroscopy

      Broken Symmetry of an Adsorbed Molecular Switch Determined by Scanning Tunneling Spectroscopy (pages 11007–11010)

      Dr. Thiruvancheril G. Gopakumar, Dr. Tugba Davran-Candan, Julia Bahrenburg, Reinhard J. Maurer, Prof. Dr. Friedrich Temps, Prof. Dr. Karsten Reuter and Prof. Dr. Richard Berndt

      Article first published online: 6 SEP 2013 | DOI: 10.1002/anie.201305027

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      An asymmetric turn: Scanning tunneling spectroscopy has been used to analyze the structure of tris[4-(phenylazo)phenyl)]amine on a Au(111) surface. A degenerate marker state serves as a sensitive probe for the structure of the adsorbed molecules.

    6. Asymmetric Catalysis

      Asymmetric Diboration of Terminal Alkenes with a Rhodium Catalyst and Subsequent Oxidation: Enantioselective Synthesis of Optically Active 1,2-Diols (pages 11011–11015)

      Kenji Toribatake and Prof. Dr. Hisao Nishiyama

      Article first published online: 2 SEP 2013 | DOI: 10.1002/anie.201305181

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      Pin it down: A highly enantioselective diboration of terminal alkenes with chiral 1 and bis(pinacolato)diboron (B2pin2) was realized. Subsequent oxidation of the diboron adducts with sodium peroxoborate readily gave the corresponding optically active 1,2-diols in high yields and high enantioselectivities.

    7. Solar Water Splitting

      A Co-catalyst-Loaded Ta3N5 Photoanode with a High Solar Photocurrent for Water Splitting upon Facile Removal of the Surface Layer (pages 11016–11020)

      Mingxue Li, Dr. Wenjun Luo, Dapeng Cao, Xin Zhao, Prof. Zhaosheng Li, Prof. Tao Yu and Prof. Zhigang Zou

      Article first published online: 14 AUG 2013 | DOI: 10.1002/anie.201305350

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      Surface exfoliation: A Ta3N5 photoanode prepared by a thermal oxidation and nitridation method shows a high solar photocurrent. This photocurrent is currently the highest achieved by a Ta3N5 photoanode. The photocurrent is obtained mainly because of facile thermal and mechanical exfoliation of the surface passivation layer of the Ta3N5 photoanode (see picture).

    8. Structural Biology

      Opsin, a Structural Model for Olfactory Receptors? (pages 11021–11024)

      Prof. Dr. Jung Hee Park, Dr. Takefumi Morizumi, Yafang Li, Joo Eun Hong, Prof. Dr. Emil F. Pai, Prof. Dr. Klaus Peter Hofmann, Prof. Dr. Hui-Woog Choe and Prof. Dr. Oliver P. Ernst

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201302374

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      Receptor–ligand interaction: Olfactory receptors (ORs) are G-protein-coupled receptors (GPCRs), which detect signaling molecules such as hormones and odorants. The structure of opsin, the GPCR employed in vision, with a detergent molecule bound deep in its orthosteric ligand-binding pocket provides a template for OR homology modeling, thus enabling investigation of the structural basis of the mechanism of odorant–receptor recognition.

    9. Mass Spectrometry

      Rapid Removal of Matrices from Small-Volume Samples by Step-Voltage Nanoelectrospray (pages 11025–11028)

      Zhenwei Wei, Shuo Han, Xiaoyun Gong, Yaoyao Zhao, Chengdui Yang, Prof. Sichun Zhang and Prof. Xinrong Zhang

      Article first published online: 23 AUG 2013 | DOI: 10.1002/anie.201302870

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      Matrix unloaded: By changing from fixed-voltage (left) to step-voltage nanoelectrospray (right), the mass-spectrometric analysis of small-volume physiological samples is possible. Separation and ionization are achieved in one process, which avoids sample loss and dilution and prevents interference by the matrix. The result is high sensitivity even for samples at the nanoliter level.

    10. Reaction Mechanisms

      The Concerted Nature of the Cyclization of Squalene Oxide to the Protosterol Cation (pages 11029–11033)

      Prof. Dr. B. Andes Hess Jr. and Prof. Dr. Lidia Smentek

      Article first published online: 3 SEP 2013 | DOI: 10.1002/anie.201302886

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      Concerted A–C ring formation: A concerted, but highly asynchronous, pathway was identified for the formation of rings A–C in the biosynthetic conversion of squalene oxide to the prosterol cation, with ring B being formed in the required boat conformation.

    11. Nanocrystal Formation

      The Formation Mechanism of Binary Semiconductor Nanomaterials: Shared by Single-Source and Dual-Source Precursor Approaches (pages 11034–11039)

      Dr. Kui Yu, Dr. Xiangyang Liu, Qun Zeng, Prof. Mingli Yang, Dr. Jianying Ouyang, Xinqin Wang and Dr. Ye Tao

      Article first published online: 4 SEP 2013 | DOI: 10.1002/anie.201304958

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      One thing in common: The formation of binary colloidal semiconductor nanocrystals from single- (M(EEPPh2)n) and dual-source precursors (metal carboxylates M(OOCR)n and phosphine chalcogenides such as E=PHPh2) is found to proceed through a common mechanism. For CdSe as a model system 31P NMR spectroscopy and DFT calculations support a reaction mechanism which includes numerous metathesis equilibriums and Se exchange reactions.

    12. Finite Nanostructures

      Templated Hierarchical Self-Assembly of Poly(p-aryltriazole) Foldamers (pages 11040–11044)

      Dr. Rueben Pfukwa, Dr. Paul H. J. Kouwer, Prof. Alan E. Rowan and Prof. Bert Klumperman

      Article first published online: 3 SEP 2013 | DOI: 10.1002/anie.201303135

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      A biomimetic approach has been used for the templated self-assembly of a helical poly(para-aryltriazole) foldamer. The solvophobic folding process yields helices that further self-assemble into long nanotubes (see picture; scale bar: 100 nm). Constructs of controlled length and chirality can be generated by applying a poly(γ-benzyl-l-glutamate) scaffold at the appropriate assembly conditions, mimicking tobacco mosaic virus self-assembly.

    13. Supramolecular Chemistry

      Release and Recovery of Guest Molecules during the Reversible Borate Gel Formation of Guest-Included Macrocyclic Boronic Esters (pages 11045–11048)

      Dr. Suguru Ito, Hisatsugu Takata, Dr. Kosuke Ono and Prof. Dr. Nobuharu Iwasawa

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201303870

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      Borate gel formation from guest-encapsulated macrocyclic boronic esters was realized by the addition of a diamine to the suspension of the boronic esters in various organic solvents, which triggered the release of the guest compounds. The guest molecules could be recovered from the borate gel by addition of an acid to remove the diamine, which facilitated the reconstruction of the initial guest-encapsulated macrocyclic boronic esters.

    14. Concave Hybrid Materials

      Pd-Cu2O and Ag-Cu2O Hybrid Concave Nanomaterials for an Effective Synergistic Catalyst (pages 11049–11053)

      Lingling Li, Xiaobin Chen, Yuen Wu, Dr. Dingsheng Wang, Dr. Qing Peng, Prof. Gang Zhou and Prof. Yadong Li

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201303912

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      Palladium and silver salts were combined with Cu2O octadecahedra in concave heterostructures. The formation of concave faces involved selective oxidative etching of Cu2O on the {100} faces and in situ growth of Pd/Ag on different sites. The structures showed superior catalytic activities to both single domains and their mixtures in a model Sonogashira-type organic reaction.

    15. Organocatalysis

      Spiro[4,4]-1,6-Nonadiene-Based Diphosphine Oxides in Lewis Base Catalyzed Asymmetric Double-Aldol Reactions (pages 11054–11058)

      Panke Zhang, Dr. Zhaobin Han, Dr. Zheng Wang and Prof. Dr. Kuiling Ding

      Article first published online: 27 AUG 2013 | DOI: 10.1002/anie.201305846

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      Symmetry swap: A C2-chiral spiro diphosphine oxide (SpinPO) has been found to be highly efficient and enantioselective in the catalysis of double-aldol reactions of ketones and aldehydes to give the corresponding optically active double-aldol products, which can be readily transformed into optically active C3- and pseudo-C3-symmetric molecules.

    16. Protein Design

      Computational Design of Helical Peptides Targeting TNFα (pages 11059–11062)

      Dr. Changsheng Zhang, Qi Shen, Bo Tang and Prof. Luhua Lai

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201305963

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      Find and bind: A computational strategy for designing single-helical peptides that can bind to a target protein was developed. After identification of potential helix-binding positions, sequences and binding conformations were derived theoretically, and explored by experimental screening. This method was successfully applied in designing peptide inhibitors for a therapeutic target, tumor necrosis factor-α (TNFα).

    17. Natural Products

      Arimetamycin A: Improving Clinically Relevant Families of Natural Products through Sequence-Guided Screening of Soil Metagenomes (pages 11063–11067)

      Dr. Hahk-Soo Kang and Prof. Sean F. Brady

      Article first published online: 3 SEP 2013 | DOI: 10.1002/anie.201305109

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      Sequence-tag-guided screening of soil environmental DNA libraries can be used to guide the discovery of new compounds with improved properties. In heterologous expression experiments the eDNA-derived arm cluster encodes arimetamycin A (see picture), an anthracycline that is more potent than clinically used natural anthracyclines and retains activity against multidrug-resistant (MDR) cancer cells.

    18. Colloidal Chemistry

      Synthesis and Site-Specific Functionalization of Tetravalent, Hexavalent, and Dodecavalent Silica Particles (pages 11068–11072)

      Dr. Anthony Désert, Céline Hubert, Zheng Fu, Lucie Moulet, Dr. Jérôme Majimel, Philippe Barboteau, Dr. Antoine Thill, Dr. Muriel Lansalot, Dr. Elodie Bourgeat-Lami, Prof. Etienne Duguet and Prof. Serge Ravaine

      Article first published online: 5 SEP 2013 | DOI: 10.1002/anie.201304273

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      Different shapes: Tetravalent, hexavalent, and dodecavalent silica particles were obtained by the growth of the silica core of binary tetrapods, hexapods, and dodecapods, respectively. The surface of the multivalent particles can be regioselectively functionalized, thereby leading to particles with anisotropic geometry and chemistry.

    19. Natural Products

      Total Synthesis of the Biscarbazole Alkaloids Murrafoline A–D by a Domino Sonogashira Coupling/Claisen Rearrangement/Electrocyclization Reaction (pages 11073–11077)

      Dr. V. Pavan Kumar, Dr. Konstanze K. Gruner, Dr. Olga Kataeva and Prof. Dr. Hans-Joachim Knölker

      Article first published online: 4 SEP 2013 | DOI: 10.1002/anie.201305993

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      Why take things one step at a time? Aryl–pyran-linked biscarbazole alkaloids of the murrafoline group (see crystal structure of murrafoline A; dark gray: C, red: O, blue: N) were accessed readily by a novel domino reaction sequence involving Sonogashira coupling, a Claisen rearrangement, and electrocyclization. The one-pot procedure enables the straightforward synthesis of these structurally challenging alkaloids in only a few steps.

    20. Phosphorus Compounds

      [3+2] Fragmentation of an [RP5Cl]+ Cage Cation Induced by an N-Heterocyclic Carbene (pages 11078–11082)

      Dr. Michael H. Holthausen, Sabrina K. Surmiak, Paul Jerabek, Prof. Dr. Gernot Frenking and Prof. Dr. Jan J. Weigand

      Article first published online: 22 AUG 2013 | DOI: 10.1002/anie.201302914

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      The cage compound [DippP5Cl][GaCl4] (Dipp=2,6-diisopropylphenyl) reacts with an NHC (N-heterocyclic carbene) by an unprecedented [3+2] fragmentation of the P5+ core. This yields an imidazoliumyl-substituted P3 species featuring a triphosphaallyl anion motif and a neutral P2 compound. The mechanism of the fragmentation reaction was elucidated by means of experimental and quantum chemical methods.

    21. Molecular Cooperative Assembly

      Three-Dimensional Macroscopic Assemblies of Low-Dimensional Carbon Nitrides for Enhanced Hydrogen Evolution (pages 11083–11087)

      Dr. Young-Si Jun, Dr. Jihee Park, Sun Uk Lee, Prof. Arne Thomas, Prof. Won Hi Hong and Prof. Galen D. Stucky

      Article first published online: 13 SEP 2013 | DOI: 10.1002/anie.201304034

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      Simple organic cooperative assembly of triazine molecules leads to three-dimensional macroscopic assemblies of low-dimensional graphitic carbon nitrides (g-CNs), for example, nanoparticles, nanotubes, and nanosheets. The approach enables the characterization of the cooperative properties and photocatalytic activities of low-dimensional g-CN materials in hydrogen evolution reactions from water under visible light.

    22. Synthetic Methods

      Highly Enantioselective Aza-Diels–Alder Reaction of 1-Azadienes with Enecarbamates Catalyzed by Chiral Phosphoric Acids (pages 11088–11091)

      Dr. Long He, Gregory Laurent, Dr. Pascal Retailleau, Dr. Benoît Folléas, Dr. Jean-Louis Brayer and Dr. Géraldine Masson

      Article first published online: 28 AUG 2013 | DOI: 10.1002/anie.201304969

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      On demand: A highly enantio- and diastereoselective synthesis of 6-amino- trisubstituted tetrahydropyridine compounds has been developed through the inverse-electron-demand aza-Diels–Alder reaction of N-aryl α,β-unsaturated ketimines with enecarbamates (E)-1. Chiral phosphoric acid catalysts achieve simultaneous activation of both the 1-azadiene and dienophile partners.

    23. Natural Sulfur Compounds

      Epidithiodiketopiperazine Biosynthesis: A Four-Enzyme Cascade Converts Glutathione Conjugates into Transannular Disulfide Bridges (pages 11092–11095)

      Dr. Daniel H. Scharf, Pranatchareeya Chankhamjon, Dr. Kirstin Scherlach, Dr. Thorsten Heinekamp, Karsten Willing, Prof. Dr. Axel A. Brakhage and Prof. Dr. Christian Hertweck

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201305059

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      Enzyme quartet: Isolation of the first sulfur-bearing intermediate of the gliotoxin pathway in Aspergillus fumigatus and successful in vitro conversion of the bisglutathione adduct into an intact epidithiodiketopiperazine by a four-enzyme cascade (including glutamyltransferase GliK and dipeptidase GliJ) revealed an outstanding adaptation of a primary metabolic pathway into natural product biosynthesis that is widespread in fungi.

    24. Reaction Mechanism

      Insertion of CS2 into Iridium–Fluorine Bonds (pages 11096–11101)

      Paul Kläring and Prof. Dr. Thomas Braun

      Article first published online: 28 AUG 2013 | DOI: 10.1002/anie.201305106

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      CS2 jumps in: C[BOND]F bond formation occurs by reactions of the fluorido complexes trans-[Ir(ArF)(F)(H)(PiPr3)2] (ArF=4-C5NF4; see scheme) with CS2 to form the fluorodithiocarbonato species trans-[Ir(ArF)(H)(κ2-(S,S)-S2CF)(PiPr3)2]. DFT studies suggest an unprecedented concerted metathesis-like mechanism for the C[BOND]F bond-formation step in which CS2 inserts into the Ir[BOND]F bond.

    25. Synthetic Methods

      Diastereospecific Nazarov Cyclization of Fully Substituted Dienones: Generation of Vicinal All-Carbon-Atom Quaternary Stereocenters (pages 11102–11105)

      Anais Jolit, Saleta Vazquez-Rodriguez, Dr. Glenn P. A. Yap and Prof. Marcus A. Tius

      Article first published online: 3 SEP 2013 | DOI: 10.1002/anie.201305218

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      No vacancy: Fully substituted dienones that are highly polarized by a vinylogous carbonate group were found to undergo a remarkably rapid and diastereospecific Nazarov cyclization that led to cyclopentenones with vicinal all-carbon-atom quaternary centers (see example; SEM=2-(trimethylsilyl)ethoxymethyl, Tf=trifluoromethanesulfonyl).

    26. Photoresponsive Nanoparticles

      A UV-Blocking Polymer Shell Prevents One-Photon Photoreactions while Allowing Multi-Photon Processes in Encapsulated Upconverting Nanoparticles (pages 11106–11109)

      Tuoqi Wu, Madeleine Barker, Khaled M. Arafeh, John-Christopher Boyer, Carl-Johan Carling and Prof. Neil R. Branda

      Article first published online: 23 AUG 2013 | DOI: 10.1002/anie.201305253

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      Sun block for nanoparticles: Unintentional photorelease triggered by UV light is a problem in photodynamic therapy. Encapsulating upconverting nanoparticles containing photoswitches in a UV-blocking amphiphilic polymer shuts down the one-photon process and only allows two-photon-driven photochemistry. Thus, UV light is blocked while NIR light can reach the nanoparticle core and trigger photorelease.

    27. Peptide Oxidation

      The Catalytically Active Copper-Amyloid-Beta State: Coordination Site Responsible for Reactive Oxygen Species Production (pages 11110–11113)

      Laure-Estelle Cassagnes, Vincent Hervé, Prof.Dr. Françoise Nepveu, Dr. Christelle Hureau, Prof.Dr. Peter Faller and Dr. Fabrice Collin

      Article first published online: 3 SEP 2013 | DOI: 10.1002/anie.201305372

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      Copper-amyloid-β ROS production: Copper ions (red sphere, see picture) have been found to accumulate in amyloid-β plaques and play a role in the generation of reactive oxygen species (ROS) within this context. Mass spectrometry studies were able to detail the sites of oxidation damage and shed new light on the mechanism of ROS production, important for the understanding of the pathogenicity of amyloid-β peptides.

    28. Synthetic Methods

      A Powerful Hydrogen-Bond-Donating Organocatalyst for the Enantioselective Intramolecular Oxa-Michael Reaction of α,β-Unsaturated Amides and Esters (pages 11114–11118)

      Dr. Yusuke Kobayashi, Yamato Taniguchi, Noboru Hayama, Dr. Tsubasa Inokuma and Prof. Dr. Yoshiji Takemoto

      Article first published online: 27 AUG 2013 | DOI: 10.1002/anie.201305492

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      Tuning the organocatalyst: An unprecedented enantioselective intramolecular oxa-Michael reaction of unactivated α,β-unsaturated amides and esters catalyzed by a powerful hydrogen-bond-donating organocatalyst has been developed. Furthermore, the products obtained from this reaction have been used for the straightforward asymmetric synthesis of several natural products and biologically important compounds.

    29. Solar Hydrogen

      Solar Hydrogen Generation by Silicon Nanowires Modified with Platinum Nanoparticle Catalysts by Atomic Layer Deposition (pages 11119–11123)

      Pengcheng Dai, Jin Xie, Matthew T. Mayer, Dr. Xiaogang Yang, Prof. Dr. Jinhua Zhan and Prof. Dr. Dunwei Wang

      Article first published online: 5 SEP 2013 | DOI: 10.1002/anie.201303813

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      Covered with Pt: A uniform catalyst profile that ensures effective radial charge collection from high-aspect-ratio Si nanowires was achieved by atomic layer deposition of Pt nanoparticles. The resulting photoelectrode permits the measurement of high photovoltages and low overpotentials, and leads to very good stability against photooxidation of Si nanowires in solar water-reduction reactions.

    30. C[BOND]H Functionalization

      Use of a Readily Removable Auxiliary Group for the Synthesis of Pyrrolidones by the Palladium-Catalyzed Intramolecular Amination of Unactivated γ C(sp3)[BOND]H Bonds (pages 11124–11128)

      Dr. Gang He, Dr. Shu-Yu Zhang, William A. Nack, Dr. Qiong Li and Prof. Dr. Gong Chen

      Article first published online: 27 AUG 2013 | DOI: 10.1002/anie.201305615

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      Easy on, easy off: Directing groups found to promote the palladium-catalyzed amination of γ C(sp3)[BOND]H and C(sp2)[BOND]H bonds of secondary amides included 5-methoxy-8-aminoquinoline, which can be removed under mild conditions (see scheme; CAN=ceric ammonium nitrate). In conjunction with a β-C[BOND]H methylation or γ-C[BOND]H arylation step, the γ-C(sp3)[BOND]H amination provided access to complex pyrrolidones from readily available precursors.

    31. Alkaloid Synthesis

      Protic-Solvent-Mediated Cycloisomerization of Quinoline and Isoquinoline Propargylic Alcohols: Syntheses of (±)-3-Demethoxyerythratidinone and (±)-Cocculidine (pages 11129–11133)

      Stephen T. Heller, Toshihiro Kiho, Alison R. H. Narayan and Prof. Richmond Sarpong

      Article first published online: 5 SEP 2013 | DOI: 10.1002/anie.201304687

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      Putting the “benz” in indolizinones: A cycloisomerization approach to benz[g]indolizinones and benz[e]indolizinones provides the first general route to these unique azacycles (see example). The utility of the benzindolizinone products was demonstrated by the application of this method to the total synthesis of the Erythrina alkaloids 3-demethoxyerythratidinone and cocculidine.

    32. Asymmetric Organocatalysis

      Functionalization of Benzylic C(sp3)[BOND]H Bonds of Heteroaryl Aldehydes through N-Heterocyclic Carbene Organocatalysis (pages 11134–11137)

      Xingkuan Chen, Prof. Dr. Song Yang, Prof. Dr. Bao-An Song and Prof. Dr. Yonggui Robin Chi

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201305861

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      Aryl aldehyde activation: Oxidative activation of 2-methylindole-3-carboxaldehyde (I) through N-heterocyclic carbene (NHC) organocatalysis generates heterocyclic ortho-quinodimethane (II) as a key intermediate. This intermediate then undergoes formal [4+2] cycloaddition with trifluoromethyl ketones or isatins to form polycyclic lactones containing a quaternary carbon center.

    33. Heterocycles

      Progress in Carbonylative [2+2+1] Cycloaddition: Utilization of a Nitrile Group as the π Component (pages 11138–11142)

      Takashi Iwata, Dr. Fuyuhiko Inagaki and Prof. Dr. Chisato Mukai

      Article first published online: 28 AUG 2013 | DOI: 10.1002/anie.201305729

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      New tricks, old reactions: The treatment of 2-(1,2-propadienyl)phenylacetonitrile derivatives with a catalytic amount of [{RhCl(CO)dppp}2] (dppp=1,3-bis(diphenylphosphanyl)propane) under a CO atmosphere produced benzo[f]oxyindole derivatives (see scheme). This aza-Pauson–Khand-type reaction was applicable to aliphatic substrates, thus resulting in the formation of the azabicyclo[3.3.0]octadienone derivatives.

    34. Smart Materials

      Hyperbranched Polycoumarates with Photofunctional Multiple Shape Memory (pages 11143–11148)

      Dr. Si-Qian Wang, Prof. Daisaku Kaneko, Dr. Maiko Okajima, Dr. Katsuaki Yasaki, Prof. Seiji Tateyama and Prof. Tatsuo Kaneko

      Article first published online: 5 SEP 2013 | DOI: 10.1002/anie.201305647

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      In good shape: The films of hyperbranched polycoumarate derivatives can undergo a reversible [2+2] cycloaddition under irradiation of UV light and behave like photomechanical elastomers. From a predetermined original shape A the photonically and thermally memorized shapes B and C were obtained. The original shape was recovered by photoirradiation (see picture; Tg=glass transition temperature).

    35. Protein Chemistry

      Modifying the Vicinity of the Isopeptide Bond To Reveal Differential Behavior of Ubiquitin Chains with Interacting Proteins: Organic Chemistry Applied to Synthetic Proteins (pages 11149–11153)

      Najat Haj-Yahya, Mahmood Haj-Yahya, Dr. Carlos A. Castañeda, Liat Spasser, Dr. Hosahalli P. Hemantha, Muhammad Jbara, Dr. Marlin Penner, Prof. Aaron Ciechanover, Prof. David Fushman and Prof. Ashraf Brik

      Article first published online: 4 SEP 2013 | DOI: 10.1002/anie.201306118

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      In every direction: Chemical protein synthesis allows the construction of 14 di-ubiquitin analogues modified in the vicinity of the isopeptide bond to examine their behavior with deubiquitinases and ubiquitin binding domains. The results set the ground for the generation of unique probes for studying the interactions of these chains with various ubiquitin-interacting proteins.

    36. Fluorescence Nanothermometers

      Intracellular Thermometry by Using Fluorescent Gold Nanoclusters (pages 11154–11157)

      Dr. Li Shang, Florian Stockmar, Naghmeh Azadfar and Prof. Dr. G. Ulrich Nienhaus

      Article first published online: 13 SEP 2013 | DOI: 10.1002/anie.201306366

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      The “gold standard” for nanothermometry: The application of ultrasmall, near-IR-emitting fluorescent gold nanoclusters (AuNCs) for temperature sensing has been explored. AuNC-based fluorescent nanothermometry features excellent thermal sensitivity and simultaneous temperature sensing and imaging in HeLa cells.

    37. Organocatalysis

      Characterization of the Key Intermediates of Carbene-Catalyzed Umpolung by NMR Spectroscopy and X-Ray Diffraction: Breslow Intermediates, Homoenolates, and Azolium Enolates (pages 11158–11162)

      Prof. Dr. Albrecht Berkessel, Veera Reddy Yatham, Silvia Elfert and Dr. Jörg-M. Neudörfl

      Article first published online: 28 AUG 2013 | DOI: 10.1002/anie.201303107

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      Caught in the act: Diamino enols, diamino dienols, azolium enolates, and azolium enols are postulated intermediates of the N-heterocyclic carbene catalyzed umpolung of aldehydes and enals. Several of these elusive reaction intermediates were generated with the saturated imidazolidin-2-ylidene SIPr (R=2,6-bis(2-propyl)phenyl) and characterized by NMR spectroscopy and X-ray crystallography.

    38. Structures and Ambident Reactivities of Azolium Enolates (pages 11163–11167)

      Dr. Biplab Maji and Prof. Dr. Herbert Mayr

      Article first published online: 29 JUL 2013 | DOI: 10.1002/anie.201303524

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      Oxygen versus carbon: Azolium enolates were generated by the reactions of N-heterocyclic carbenes (NHCs) with methyl phenyl ketene and characterized by X-ray crystallography. Kinetic studies show that the enolate oxygen is 20 times more nucleophilic than the carbon atom, but under thermodynamic control exclusive C-addition products were formed.

    39. Natural Product Synthesis

      Total Synthesis of (+)-Crotogoudin (pages 11168–11171)

      Simon Breitler and Prof. Dr. Erick M. Carreira

      Article first published online: 26 AUG 2013 | DOI: 10.1002/anie.201305822

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      Fellowship of the ring: The first total synthesis of (+)-crotogoudin, a 3,4-seco-atisane diterpenoid natural product, is reported. Asymmetric access to the bicyclo[2.2.2]octane core is achieved through a desymmetrization of a meso-diketone with baker's yeast (LG=leaving group, PG=protecting group). A SmI2-induced radical cyclopropane-opening/annulation/elimination cascade affords the suitably decorated tetracyclic structure of (+)-crotogoudin. The synthesis led to revision of the reported optical rotation of the natural product and to assignment of its absolute configuration as an ent-atisane (5R,10R).

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