Angewandte Chemie International Edition

Cover image for Vol. 52 Issue 20

May 10, 2013

Volume 52, Issue 20

Pages 5187–5405

  1. Cover Pictures

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. You have free access to this content
      Cover Picture: Tetrameric ααββ Aggregate Formation by Stereoisomeric Bidomain Helicene Oligomers (Angew. Chem. Int. Ed. 20/2013) (page 5187)

      Dr. Wataru Ichinose, Jun Ito and Prof. Dr. Masahiko Yamaguchi

      Article first published online: 2 MAY 2013 | DOI: 10.1002/anie.201303075

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      Tetrameric aggregates with an ααββ structure are formed by a method using stereoisomeric bidomain oligomers for the α- and β-subunits, as described in the Communication on page 5290 ff. by M. Yamaguchi et al‥ Mixing the dimeric αα and ββ homoaggregates gave tetrameric ααββ heteroaggregates without formation of higher and lower aggregates. The tetrameric aggregate reversibly changed its structure between the dimeric homoaggregates on heating and cooling, and gelation occurred in toluene by polymerization.

    2. You have free access to this content
      Inside Cover: Synthesis and Application of β-Substituted Pauson–Khand Adducts: Trifluoromethyl as a Removable Steering Group (Angew. Chem. Int. Ed. 20/2013) (page 5188)

      Nuria Aiguabella, Dr. Carlos del Pozo, Prof. Xavier Verdaguer, Prof. Santos Fustero and Prof. Antoni Riera

      Article first published online: 22 APR 2013 | DOI: 10.1002/anie.201303054

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      Full steam ahead to β-substituted Pauson–Khand adducts: By using the trifluoromethyl group as a removable steering group, A. Riera and co-workers synthesized the previously unknown regioisomers of the Pauson–Khand reaction of terminal alkynes, as they describe in their Communication on page 5355 ff The synthetic potential of the new adducts has been shown by a short formal synthesis of α-cuparenone (artwork by Pau Martin Malpartida from a picture of Leo Reynolds).

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      Inside Back Cover: Formation of a Homo Double Helix of a Conjugated Polymer with Carboxy Groups and Amplification of the Macromolecular Helicity by Chiral Amines Sandwiched between the Strands (Angew. Chem. Int. Ed. 20/2013) (page 5407)

      Wataru Makiguchi, Dr. Shinzo Kobayashi, Dr. Yoshio Furusho and Prof. Dr. Eiji Yashima

      Article first published online: 22 APR 2013 | DOI: 10.1002/anie.201303053

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      A π-conjugated polymer with carboxy groups forms a racemic double helix through self-association. However, in the presence of chiral amines, it forms a unique one-handed double helix in which the strands sandwich pairs of chiral amines through cyclic hydrogen-bonding networks. In their Communication on page 5275 ff., E. Yashima et al. report the transferal of chiral information from the amines to the polymer backbone with remarkable amplification of the helical chirality.

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      Back Cover: Catalytic Phenol Hydroxylation with Dioxygen: Extension of the Tyrosinase Mechanism beyond the Protein Matrix (Angew. Chem. Int. Ed. 20/2013) (page 5408)

      Dr. Alexander Hoffmann, Cooper Citek, Dr. Stephan Binder, Arne Goos, Dr. Michael Rübhausen, Oliver Troeppner, Prof. Dr. Ivana Ivanović-Burmazović, Prof. Dr. Erik C. Wasinger, Prof. Dr. T. Daniel P. Stack and Prof. Dr. Sonja Herres-Pawlis

      Article first published online: 22 APR 2013 | DOI: 10.1002/anie.201303052

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      Translating the catalytic mechanism of an enzyme to a synthetic complex is a challenging endeavor. In their Communication on page 5398 ff., S. Herres-Pawlis, T. D. P. Stack, and co-workers present a complex capable of the efficient catalytic oxidation of phenols to quinones by using dioxygen. The mechanism of the synthetic system is similar to that of tyrosinase, yet the substrate scope extends beyond that of the enzyme. Thus this work fulfills a goal of bioinspired chemistry.

  2. Graphical Abstract

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. Graphical Abstract: Angew. Chem. Int. Ed. 20/2013 (pages 5191–5203)

      Article first published online: 3 MAY 2013 | DOI: 10.1002/anie.201390019

  3. Corrigenda

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. You have free access to this content
      Corrigendum: Elucidating the Biosynthetic Pathway for Vibralactone: A Pancreatic Lipase Inhibitor with a Fused Bicyclic β-Lactone (page 5203)

      Dr. Pei-Ji Zhao, Yan-Long Yang, Prof. Dr. Liangchen Du, Prof. Dr. Ji-Kai Liu and Prof. Ying Zeng

      Article first published online: 3 MAY 2013 | DOI: 10.1002/anie.201302356

      This article corrects:
    2. You have free access to this content
      Corrigendum: Catalytic Dynamic Kinetic Resolutions with N-Heterocyclic Carbenes: Asymmetric Synthesis of Highly Substituted β-Lactones (page 5203)

      Daniel T. Cohen, Dr. Chad C. Eichman, Eric M. Phillips, Emily R. Zarefsky and Prof. Karl A. Scheidt

      Article first published online: 3 MAY 2013 | DOI: 10.1002/anie.201302333

      This article corrects:
  4. News

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

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. Jun-An Ma (page 5212)

      Article first published online: 5 FEB 2013 | DOI: 10.1002/anie.201209481

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      “My biggest motivation is curiosity. Guaranteed to make me laugh are Charlie Chaplin movies …” This and more about Jun-An Ma can be found on page 5212.

  6. News

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

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. Protein–Ligand Interactions. Methods and Principles in Medicinal Chemistry Series, Volume 53. Edited by Holger Gohlke. (pages 5214–5215)

      Volkhard Helms

      Article first published online: 3 APR 2013 | DOI: 10.1002/anie.201300736

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      Wiley-VCH, Weinheim, 2012. 339 pp., hardcover, € 139.00.—ISBN 978-3527329663

  8. Highlight

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. Lewis Acid Catalysis

      Si[BOND]H Bond Activation: Bridging Lewis Acid Catalysis with Brookhart’s Iridium(III) Pincer Complex and B(C6F5)3 (pages 5216–5218)

      Dr. Tobias Robert and Prof. Dr. Martin Oestreich

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201301205

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      Different but almost equal: The striking similarities between Brookhart's iridium(III) pincer complex and the electron-deficient tris(pentafluorophenyl)borane in transformations involving Si[BOND]H bond activation are highlighted. Coordination of the Si[BOND]H bond to either Lewis acid enhances the electrophilicity of the silicon atom, thereby enabling its transfer to various Lewis basic groups (see scheme, Do=acetone).

  9. Essay

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. Vegetable Oil Hydrogenation

      Is there still a Future for Hydrogenated Vegetable Oils? (pages 5220–5226)

      Dr. An Philippaerts, Prof. Pierre A. Jacobs and Prof. Bert F. Sels

      Article first published online: 3 APR 2013 | DOI: 10.1002/anie.201209731

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      For over a century, catalytic hydrogenation of vegetable oils has been an important process in the food industry, but today, it has lost much of its former popularity, because of the detrimental trans fatty acids as side products. However, the design of novel hydrogenation catalysts and the development of new strategies to remove trans isomers enable the production of trans-free hydrogenated fat products with desirable functionality.

  10. Review

    1. Top of page
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    3. Graphical Abstract
    4. Corrigenda
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    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. Main Group Organometallic Chemistry

      Structurally Defined Allyl Compounds of Main Group Metals: Coordination and Reactivity (pages 5228–5246)

      Dipl.-Chem. Crispin Lichtenberg and Prof. Dr. Jun Okuda

      Article first published online: 5 APR 2013 | DOI: 10.1002/anie.201208942

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      No longer an aside: The allyl chemistry of main group metals was traditionally less investigated, but there is now a fundamental understanding of metal–allyl interactions. Furthermore, reactivity trends and new allyl-specific reaction patterns have been identified. In this Review, the coordination modes and reactivity of allyl compounds of main group metals as well as trends in the periodic system of the elements (PSE) are discussed.

  11. Communications

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. Corrigenda
    5. News
    6. Author Profile
    7. News
    8. Book Review
    9. Highlight
    10. Essay
    11. Review
    12. Communications
    1. Electrochemistry

      An Efficient Three-Dimensional Oxygen Evolution Electrode (pages 5248–5253)

      Jun Wang, Hai-xia Zhong, Yu-ling Qin and Prof. Xin-bo Zhang

      Article first published online: 5 APR 2013 | DOI: 10.1002/anie.201301066

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      Oxygen evolution: A 3D nickel foam/porous carbon/anodized nickel electrode was designed for the oxygen evolution reaction (see picture). The conductive porous carbon membrane, which is derived from a zeolite imidazolate framework, plays a key role as an interlayer to both protect the inner instable Ni foam and support the outermost oxygen-evolving Ni catalyst layer.

    2. Liquid Crystals

      A Modulated Helical Nanofilament Phase (pages 5254–5257)

      Dr. Ethan Tsai, Dr. Jacqueline M. Richardson, Dr. Eva Korblova, Dr. Michi Nakata, Dr. Dong Chen, Yongqiang Shen, Renfan Shao, Prof. Dr. Noel A. Clark and Prof. Dr. David M. Walba

      Article first published online: 19 APR 2013 | DOI: 10.1002/anie.201209453

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      A new liquid crystal phase, denoted modulated helical nanofilament (HNF(mod)), is formed from a very simple class of biphenyl carboxylates lacking the benzylidene aniline moieties typically found in HNF mesogens. The HNF(mod) phase represents a novel kind of nanoparticle possessing stacked aromatic rings, with potential applications in organic electronics.

    3. Molecular Imaging of Paintings

      Noninvasive Analysis of Paintings by Mid-infrared Hyperspectral Imaging (pages 5258–5261)

      Dr. Francesca Rosi, Dr. Costanza Miliani, René Braun, Dr. Roland Harig, Diego Sali, Prof. Brunetto G. Brunetti and Prof. Antonio Sgamellotti

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201209929

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      Cultural detective work: Remote hyperspectral imaging in the mid-infrared region enables the identification and localization of the painting materials used by artists (see brightness temperature difference image overlayed with the corresponding portion of the painting Sestante 10 by Alberto Burri and IR reflection spectra for this area). The resulting molecular images are thus of great value for art conservation.

    4. Imaging Nanoclusters in 3D

      Three-Dimensional Structural Analysis of MgO-Supported Osmium Clusters by Electron Microscopy with Single-Atom Sensitivity (pages 5262–5265)

      Ceren Aydin, Apoorva Kulkarni, Miaofang Chi, Prof. Nigel D. Browning and Prof. Bruce C. Gates

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201300238

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      Size, shape, nuclearity: Aberration-corrected scanning transmission electron microscopy was used to determine the 3D structures of MgO-supported Os3, Os4, Os5, and Os10 clusters, which have structures nearly matching those of osmium carbonyl compounds with known crystal structures. The samples are among the best-defined supported catalysts.

    5. Anomalous Thermal Expansion

      Negative Thermal Expansion in LnCo(CN)6 (Ln=La, Pr, Sm, Ho, Lu, Y): Mechanisms and Compositional Trends (pages 5266–5270)

      Dr. Samuel G. Duyker, Dr. Vanessa K. Peterson, Prof. Gordon J. Kearley, Dr. Anibal J. Ramirez-Cuesta and Prof. Cameron J. Kepert

      Article first published online: 9 APR 2013 | DOI: 10.1002/anie.201300619

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      RUM with a twist: The magnitude of negative thermal expansion (NTE) in the LnCo(CN)6 coordination frameworks increases with Ln ion radius rLn. The framework structure contains an unusual locally unstable trigonal prismatic LnN6 unit that participates in an NTE-contributing vibrational mode by twisting about its axis at low energies. This contrasts with the rigid unit modes (RUMs) prevalent in other systems.

    6. Arene Halogenation

      Regioselective Arene Halogenation using the FAD-Dependent Halogenase RebH (pages 5271–5274)

      James T. Payne, Mary C. Andorfer and Prof. Jared C. Lewis

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201300762

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      Together we're strong: Co-expression of the halogenase RebH with GroEL/ES and fusion of the flavin reductase RebF to MBP enabled production of both enzymes on scales sufficient for preparative regioselective oxidative halogenation of arenes. The activity and selectivity of RebH contrasts with those reported for the structurally homologous halogenase PrnA, which only enabled halogenation of nonnatural substrates at their most electronically activated positions.

    7. Helical Structures

      Formation of a Homo Double Helix of a Conjugated Polymer with Carboxy Groups and Amplification of the Macromolecular Helicity by Chiral Amines Sandwiched between the Strands (pages 5275–5279)

      Wataru Makiguchi, Dr. Shinzo Kobayashi, Dr. Yoshio Furusho and Prof. Dr. Eiji Yashima

      Article first published online: 5 APR 2013 | DOI: 10.1002/anie.201301005

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      Sandwiched amines: A π-conjugated polymer with carboxy groups self-associates to form a racemic double helix. In contrast, with chiral amines it forms a unique one-handed double helix, in which the strands sandwich pairs of chiral amines through cyclic hydrogen-bonding networks (see picture). The chiral information of the amines is transferred to the polymer backbones with remarkable amplification of the helical chirality.

    8. Zeolite Films

      Uniform Si-CHA Zeolite Layers Formed by a Selective Sonication-Assisted Deposition Method (pages 5280–5284)

      Eunjoo Kim, Wanxi Cai, Dr. Hionsuck Baik and Prof. Jungkyu Choi

      Article first published online: 10 APR 2013 | DOI: 10.1002/anie.201301265

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      Discrimination against the majority: The broad size distribution of conventional near-cubic Si-CHA (all-silica chabazite) zeolites impedes the formation of a close-packed layer, which is critical for the manufacture of zeolite films by secondary growth. Although present in lower abundance, platelike Si-CHA particles cosynthesized with near-cubic particles were deposited selectively on an α-Al2O3 disk to form a uniform layer.

    9. Aureothin Polyketide Synthase

      Multifactorial Control of Iteration Events in a Modular Polyketide Assembly Line (pages 5285–5289)

      Benjamin Busch, Nico Ueberschaar, Swantje Behnken, Yuki Sugimoto, Martina Werneburg, Nelly Traitcheva, Jing He and Prof. Dr. Christian Hertweck

      Article first published online: 18 APR 2013 | DOI: 10.1002/anie.201301322

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      Freedom and control: First insights into the rare programmed iteration of an individual polyketide synthase (PKS) module were obtained from the analysis and mutation of aureothin (1) synthase. The first ketosynthase (KS) domain primes the PKS, allowing intermediate retrotransfer. Addition of a designated loading module results in a complete loss of iteration. The downstream KS functions as a gatekeeper for correct chain length.

    10. Tetrameric Heteroaggregation

      Tetrameric ααββ Aggregate Formation by Stereoisomeric Bidomain Helicene Oligomers (pages 5290–5294)

      Dr. Wataru Ichinose, Jun Ito and Prof. Dr. Masahiko Yamaguchi

      Article first published online: 9 APR 2013 | DOI: 10.1002/anie.201301463

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      How to aggregate your domains: A method of forming tetrameric aggregates with an ααββ structure has been developed using stereoisomeric bidomain oligomers. Upon mixing the oligomers, a tetrameric ααββ aggregate was obtained by heteroaggregation at the ethynyl domain. The tetrameric aggregate reversibly changed its structure between the dimeric homoaggregates on heating and cooling, whereas gelation by polymerization occurred in toluene.

    11. Heterogeneous Catalysis

      Supported Au–Cu Bimetallic Alloy Nanoparticles: An Aerobic Oxidation Catalyst with Regenerable Activity by Visible-Light Irradiation (pages 5295–5299)

      Dr. Yoshitsune Sugano, Dr. Yasuhiro Shiraishi, Dr. Daijiro Tsukamoto, Dr. Satoshi Ichikawa, Dr. Shunsuke Tanaka and Prof. Takayuki Hirai

      Article first published online: 12 APR 2013 | DOI: 10.1002/anie.201301669

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      Rejuvenating sunlight: Supported Au–Cu bimetallic alloy nanoparticles promote aerobic oxidation at room temperature under visible light (λ>450 nm) irradiation with little deactivation by the oxidation of surface Cu atoms by oxygen. This is achieved through the reduction of oxidized surface Cu atoms by the surface Au atoms, a process which is activated by visible-light irradiation, even by sunlight.

    12. Natural Product Synthesis

      A Convergent Total Synthesis of 19-Hydroxysarmentogenin (pages 5300–5304)

      Ken Mukai, Dr. Daisuke Urabe, Dr. Satoshi Kasuya, Naoto Aoki and Prof. Dr. Masayuki Inoue

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201302067

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      19 in 19: A convergent total synthesis of 19-hydroxysarmentogenin has been achieved, starting from three simple fragments. The desired product was synthesized in 19 steps from the AB ring system with the installation of six stereocenters and the formation of three C[BOND]C bonds.

    13. C[BOND]H Activation

      You have full text access to this OnlineOpen article
      Total Synthesis of (+)-Linoxepin by Utilizing the Catellani Reaction (pages 5305–5308)

      Dr. Harald Weinstabl, Dr. Marcel Suhartono, Zafar Qureshi and Prof. Dr. Mark Lautens

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201302327

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      Molecular intelligence: The structurally novel lignan (+)-linoxepin is synthesized in an eight-step sequence. The enantioselective synthesis features the palladium-catalyzed Catellani reaction as the key step. In this highly convergent multicomponent reaction, two new carbon–carbon bonds are formed, one of which results from a C[BOND]H bond functionalization.

    14. Asymmetric Catalysis

      Effective Synthesis of Chiral N-Fluoroaryl Aziridines through Enantioselective Aziridination of Alkenes with Fluoroaryl Azides (pages 5309–5313)

      Dr. Li-Mei Jin, Dr. Xue Xu, Dr. Hongjian Lu, Dr. Xin Cui, Dr. Lukasz Wojtas and Prof. Dr. X. Peter Zhang

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201209599

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      The CoII complex of a D2-symmetric chiral porphyrin ([Co(D2-Por*)], see scheme) is a highly effective catalyst for the enantioselective aziridination of alkenes with fluoroaryl azides. The reaction can be performed at RT with low catalyst loading, and the olefin is the limiting reagent. Furthermore, the reaction is tolerant toward different combinations of aromatic olefins and fluoroaryl azides.

    15. Rhodium-Catalyzed Asymmetric Arylative Cyclization of meso-1,6-Dienynes Leading to Enantioenriched cis-Hydrobenzofurans (pages 5314–5318)

      Zhi-Tao He, Bing Tian, Yuki Fukui, Prof. Dr. Xiaofeng Tong, Prof. Dr. Ping Tian and Prof. Guo-Qiang Lin

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201300137

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      In tandem: The title reaction of cyclohexadienone-containing meso-1,6-dienynes with arylboronic acids through a tandem arylrhodation/conjugate addition sequence has been realized, and provides a novel approach to the enantioenriched cis-hydrobenzofurans with both excellent yields and enantioselectivities. binap=2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl, Boc=tert-butoxycarbonyl.

    16. Synthetic Methods

      Amine-Promoted Asymmetric (4+2) Annulations for the Enantioselective Synthesis of Tetrahydropyridines: A Traceless and Recoverable Auxiliary Strategy (pages 5319–5322)

      Pengfei Hu, Jian Hu, Prof. Jiajun Jiao and Dr. Xiaofeng Tong

      Article first published online: 9 APR 2013 | DOI: 10.1002/anie.201300526

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      Gone, without a trace: The in situ reaction of 2-(acetoxymethyl)buta-2,3-dienoate and a secondary amine produces a 2-methylene-3-oxobutanoate equivalent that can be used in asymmetric [4+2] annulations with N-tosylimines to provide tetrahydropyridines in good to excellent yields and enantioselectivities. The amine is easily recovered and acts as a traceless auxiliary.

    17. Quinoline Synthesis

      Copper(II)-Catalyzed Three-Component Cascade Annulation of Diaryliodoniums, Nitriles, and Alkynes: A Regioselective Synthesis of Multiply Substituted Quinolines (pages 5323–5327)

      Yong Wang, Prof. Dr. Chao Chen, Jing Peng and Prof. Dr. Ming Li

      Article first published online: 9 APR 2013 | DOI: 10.1002/anie.201300586

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      Three become one: Multiply substituted quinolines were synthesized from diaryliodoniums, alkynes, and nitriles by a CuII-catalyzed method. This cascade annulation is highly regioselective, step-economic, flexible with regard to the functional groups, and could potentially be applied to the synthesis of complex molecules.

    18. C[BOND]F Activation

      Catalytic Hydrodefluorination of Fluoromethanes at Room Temperature by Silylium-ion-like Surface Species (pages 5328–5332)

      Dr. Mike Ahrens, Priv.-Doz. Dr. Gudrun Scholz, Prof. Dr. Thomas Braun and Prof. Dr. Erhard Kemnitz

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201300608

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      'Al'l about F: Aluminum chlorofluoride (ACF) catalyzes the hydrodefluorination, as well as Friedel–Crafts reactions of fluorinated methanes in the presence of Et3SiH. A surface-bound silylium-ion-like species is considered to be a crucial intermediate in achieving the C[BOND]F bond cleavage.

    19. Synthetic Methods

      Diastereodivergent Carbometalation/Oxidation/Selective Ring Opening: Formation of All-Carbon Quaternary Stereogenic Centers in Acyclic Systems (pages 5333–5337)

      Dr. Pierre-Olivier Delaye, Dr. Dorian Didier and Prof. Dr. Ilan Marek

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201300664

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      A twofer: The title reaction sequence for cyclopropenes allows the preparation of aldehydes bearing α-quaternary stereocenters in a one pot-reaction from readily available starting materials. Through a diastereodivergent carbometalation reaction, both enantiomers of the corresponding aldehyde were obtained from the same cyclopropene derivative (see scheme).

    20. Asymmetric Allylation

      Highly Stereoselective Synthesis of Z-Homoallylic Alcohols by Kinetic Resolution of Racemic Secondary Allyl Boronates (pages 5338–5341)

      Celia A. Incerti–Pradillos, Dr. Mikhail A. Kabeshov and Prof. Dr. Andrei V. Malkov

      Article first published online: 10 APR 2013 | DOI: 10.1002/anie.201300709

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      α to Z: Racemic α-chiral allyl boronates, which are readily synthesized from the respective primary allyl halides, undergo a highly efficient kinetic resolution in a face- and Z-selective allylation of aldehydes catalyzed by the chiral Brønsted acid (R)-TRIP (see scheme; Epin=tetraethylethylene glycol).

    21. Hydrogen Bonding Control

      Differential Hydrogen Bonding in Human CYP17 Dictates Hydroxylation versus Lyase Chemistry (pages 5342–5345)

      Michael Gregory, Dr. Piotr J. Mak, Prof. Stephen G. Sligar and Prof. James R. Kincaid

      Article first published online: 10 APR 2013 | DOI: 10.1002/anie.201300760

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      Consequences of alternative H-bonding: Raman spectra of oxygenated intermediates of Nanodisc-incorporated human CYP17 in the presence of natural substrates (pregnenolone and progesterone) directly confirm that substrate structure effectively alters hydrogen-bonding interactions with the critical Fe–O–O fragment and dictates its predisposition for one of two alternative reaction pathways. Such substrate control has profound physiological implications.

    22. Trifluoromethylation

      Copper-Catalyzed Trifluoromethylation of N,N-Dialkylhydrazones (pages 5346–5349)

      Etienne Pair, Dr. Nuno Monteiro, Dr. Didier Bouyssi and Prof. Dr. Olivier Baudoin

      Article first published online: 8 APR 2013 | DOI: 10.1002/anie.201300782

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      Mild and practical: Trifluoromethylation of (hetero)aromatic aldehyde N,N-dialkylhydrazones was achieved at room temperature by using Togni's trifluoromethylation reagent under CuCl catalysis (see scheme). This simple reaction is believed to occur by a CF3-radical-transfer mechanism and yields useful trifluoromethylated building blocks.

    23. Homogeneous Catalysis

      Copper-Catalyzed γ-Selective and Stereospecific Direct Allylic Alkylation of Terminal Alkynes: Synthesis of Skipped Enynes (pages 5350–5354)

      Yusuke Makida, Yurie Takayama, Prof. Dr. Hirohisa Ohmiya and Prof. Dr. Masaya Sawamura

      Article first published online: 9 APR 2013 | DOI: 10.1002/anie.201300785

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      Skipping out: The title reaction using internal secondary allylic phosphates proceeded with excellent γ regioselectivity and E stereoselectivity to give skipped enynes. Enantioenriched secondary allylic phosphates proceeded with 1,3-anti stereochemistry to afford the corresponding chiral 1,4-enynes, which were used for various derivatizations and the formal total synthesis of a GnRH antagonist. phen=1,10-phenanthroline.

    24. Synthetic Methods

      Synthesis and Application of β-Substituted Pauson–Khand Adducts: Trifluoromethyl as a Removable Steering Group (pages 5355–5359)

      Nuria Aiguabella, Dr. Carlos del Pozo, Prof. Xavier Verdaguer, Prof. Santos Fustero and Prof. Antoni Riera

      Article first published online: 10 APR 2013 | DOI: 10.1002/anie.201300907

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      Against the rules: The synthesis of the previously unknown β-substituted regioisomers of the intermolecular Pauson–Khand reaction of terminal alkynes is reported. This regiochemistry was achieved by using the trifluoromethyl group as a removable directing group on the alkyne.

    25. Control of Remote Stereochemistry in the Synthesis of Spirocyclic Oxindoles: Vinylogous Organocascade Catalysis (pages 5360–5363)

      Xu Tian and Prof. Dr. Paolo Melchiorre

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201301017

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      Remote control: The title reaction facilitates the synthesis of complex chiral molecules while selectively forging multiple stereocenters at distant positions, namely five and six bond lengths away from the catalyst chiral fragment (see scheme; Boc=tert-butoxycarbonyl). The potential of the strategy is demonstrated through the one-step preparation of spirocyclopentane oxindoles having four contiguous stereocenters.

    26. N-Heterocycles

      A Magnesium-Mediated Cascade Assembly for the Atom-Economical Synthesis of Bis(imidazolidine-2,4-dione)s (pages 5364–5367)

      Prof. Michael S. Hill, David J. Liptrot and Dr. Mary F. Mahon

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201301489

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      Bicycle race: Structurally complex bis(imidazolidine-2,4-dione) molecules may be synthesized with complete atom-efficiency from simple building blocks by a kinetically controlled magnesium-mediated cascade of intermolecular isocyanate insertion and intramolecular alkyne hydroamination reaction steps.

    27. Asymmetric Synthesis

      A Catalytic Asymmetric Synthesis of Polysubstituted Piperidines Using a Rhodium(I)-Catalyzed [2+2+2] Cycloaddition Employing a Cleavable Tether (pages 5368–5371)

      Dr. Timothy J. Martin and Prof. Tomislav Rovis

      Article first published online: 19 APR 2013 | DOI: 10.1002/anie.201301741

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      Break the cycle: The title reaction proceeds with a variety of alkyne substrates in good yield and high enantioselectivity. Upon reduction of the vinylogous amide in high diastereoselectivity (>19:1) and cleavage of the tether, N-methylpiperidine products with functional group handles can be accessed (see scheme).

    28. Dinitrogen Hapticity

      Redox-Induced N2 Hapticity Switching in Zirconocene Dinitrogen Complexes (pages 5372–5376)

      Scott P. Semproni, Donald J. Knobloch, Carsten Milsmann and Prof. Paul J. Chirik

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201301800

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      N2 shuffle: One-electron reduction of the ansa-zirconocene complex with a side-on dinitrogen ligand furnished the corresponding anion in which the hapticity of the N2 ligand changed to end-on. Oxidation of the anion regenerates the neutral complex with concomitant change in N2 hapticity. The zirconocene complexes with unusual (N2)3−/(N2) ligands have been fully characterized. Ad=adamantyl.

    29. DNA Nanoparticles

      Dual Responsive, Stabilized Nanoparticles for Efficient In Vivo Plasmid Delivery (pages 5377–5381)

      Dr. Hua Wei, Lisa R. Volpatti, Dr. Drew L. Sellers, Don O. Maris, Ian W. Andrews, Ashton S. Hemphill, Leslie W. Chan, David S. H. Chu, Prof. Philip J. Horner and Prof. Suzie H. Pun

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201301896

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      A small case of love and hate: A block-statistical copolymer combining reversible hydrophobization and statistical hydrophilization allows the preparation of pH value- and reduction-responsive nanoparticles (polyplexes) for efficient in vivo plasmid delivery.

    30. Oxidized Phospholipids

      Synthesis of Epoxyisoprostanes: Effects in Reducing Secretion of Pro-inflammatory Cytokines IL-6 and IL-12 (pages 5382–5385)

      Julian Egger, Peter Bretscher, Dr. Stefan Freigang, Prof. Dr. Manfred Kopf and Prof. Dr. Erick M. Carreira

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201300739

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      Anti-inflammatory: The efficient and general synthetic route to the elusive epoxyisoprostanoid phospholipids PECPC and PEIPC, along with the isoprostanoids EC and EI, relies on a number of stereo- and chemoselective steps, including a C[BOND]H insertion for the rapid construction of the cyclopentanone ring. The synthesized compounds display unprecedented biological activity in reducing the secretion of pro-inflammatory cytokines.

    31. C[BOND]H Activation

      Mild Rhodium(III)-Catalyzed Direct C[BOND]H Allylation of Arenes with Allyl Carbonates (pages 5386–5389)

      Dr. Honggen Wang, Nils Schröder and Prof. Dr. Frank Glorius

      Article first published online: 10 APR 2013 | DOI: 10.1002/anie.201301165

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      All(yl) possible! A rhodium(III)-catalyzed intermolecular direct C[BOND]H allylation reaction utilizing readily accessible allyl carbonates was developed. This method allows the allylation of electron-neutral arenes, providing complete γ-selectivity, high isomeric ratio, good substrate scope, and excellent functional group compatibility.

    32. Terpenes

      A Short Enantioselective Total Synthesis of (−)-Englerin A (pages 5390–5392)

      M. Sc. Martin Zahel, B. Sc. Anton Keßberg and Prof. Dr. Peter Metz

      Article first published online: 15 APR 2013 | DOI: 10.1002/anie.201301247

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      Selective oxidations of dienone 2 as well as a ring-closing metathesis to give the hydroazulene framework enabled the 12-step preparation of title compound 1 from (−)-photocitral A (3), which is in turn rapidly available from (−)-isopulegol through dual catalysis.

    33. C[BOND]H Activation

      Mild Rhodium(III)-Catalyzed Cyclization of Amides with α,β-Unsaturated Aldehydes and Ketones to Azepinones: Application to the Synthesis of the Homoprotoberberine Framework (pages 5393–5397)

      Dr. Zhuangzhi Shi, Christoph Grohmann and Prof. Dr. Frank Glorius

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201301426

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      Seven! The title reaction can be described as an intermolecular annulation involving tandem C[BOND]H activation, cyclization to give the seven-membered ring, and condensation steps. Biologically interesting azepinone derivatives can be prepared in this way. The synthetic potential of this method was demonstrated by the construction of the homoprotoberberine ring system.

    34. Tyrosinase Model

      Catalytic Phenol Hydroxylation with Dioxygen: Extension of the Tyrosinase Mechanism beyond the Protein Matrix (pages 5398–5401)

      Dr. Alexander Hoffmann, Cooper Citek, Dr. Stephan Binder, Arne Goos, Prof. Dr. Michael Rübhausen, Oliver Troeppner, Prof. Dr. Ivana Ivanović-Burmazović, Prof. Dr. Erik C. Wasinger, Prof. Dr. T. Daniel P. Stack and Prof. Dr. Sonja Herres-Pawlis

      Article first published online: 22 APR 2013 | DOI: 10.1002/anie.201301249

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      A new catalyst (see structure) hydroxylates phenols with O2 via a stable side-on peroxide complex, which is similar to the active site of tyrosinase in terms of the ligand environment and its spectroscopic properties. The catalytic oxidation of phenols to quinones proceeds at room temperature in the presence of NEt3 and even non-native substrates can be oxidized catalytically. The reaction mechanism is analogous to that of the enzyme-catalyzed reaction.

    35. Natural Products

      Isolation, Structure Elucidation, and Biological Activity of Maltepolides: Remarkable Macrolides from Myxobacteria (pages 5402–5405)

      Dr. Herbert Irschik, Dr. Peter Washausen, Dr. Florenz Sasse, Dr. Jörg Fohrer, Dr. Volker Huch, Prof. Dr. Rolf Müller and Dr. Evgeny V. Prusov

      Article first published online: 16 APR 2013 | DOI: 10.1002/anie.201210113

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      Epoxide “swing”: A family of polyketide macrolactones originating from maltepolide E was discovered in Sorangium cellulosum So ce1485. Their structure was established by NMR experiments, molecular modeling, and X-ray crystallography. Maltepolides induce rather rare morphological changes in the dividing transformed cell lines (see picture in the background).

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