Angewandte Chemie International Edition

Cover image for Vol. 52 Issue 15

April 8, 2013

Volume 52, Issue 15

Pages 4041–4272

  1. Cover Pictures

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. News
    5. Author Profile
    6. News
    7. Book Review
    8. Essay
    9. Minireview
    10. Review
    11. Communications
    1. You have free access to this content
      Cover Picture: Protection and Deprotection of DNA—High-Temperature Stability of Nucleic Acid Barcodes for Polymer Labeling (Angew. Chem. Int. Ed. 15/2013) (page 4041)

      M. Sc. Daniela Paunescu, Dr. Roland Fuhrer and Dr. Robert N. Grass

      Version of Record online: 13 MAR 2013 | DOI: 10.1002/anie.201301653

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      When DNA is encapsulated in a silica sphere, the encoded information can be protected for storage and distribution, much in the way a bottle protects the message inside from the rough sea. As R. N. Grass et al. describe in their Communication on page 4269 ff., a silica layer only 10 nm thick is sufficient to protect DNA from high temperatures and aggressive radical conditions. The glass can be broken by reaction with HF and the information recovered for biochemical analysis.

    2. You have free access to this content
      Inside Cover: Oxidative Cyclodimerization After Tandem Cyclization of Dehydrobenzo[14]annulenes Induced by Alkyllithium (Angew. Chem. Int. Ed. 15/2013) (page 4042)

      Shunpei Nobusue, Dr. Akihiro Shimizu, Prof. Kenji Hori, Dr. Ichiro Hisaki, Prof. Mikiji Miyata and Prof. Yoshito Tobe

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201301655

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      Transannular cyclization of dehydrobenzoannulenes is a powerful method to construct new carbon frameworks that are otherwise difficult to achieve. In their Communication on page 4184 ff., Y. Tobe and co-workers show that the reaction of dehydrobenzo[14]annulenes with n-butyllithium leads to an unprecedented oxidative cyclodimerization to form eight-membered-ring products, following threefold transannular bond formations across a 14-membered ring.

    3. You have free access to this content
      Inside Back Cover: Polymer Phase-Transition Behavior Driven by a Charge-Transfer Interaction (Angew. Chem. Int. Ed. 15/2013) (page 4273)

      Shogo Amemori, Dr. Kenta Kokado and Prof. Dr. Kazuki Sada

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201301704

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      The lower critical solution temperature (LCST), is a well-established phase-transition behavior of polymer solutions, and it has attracted much interest with regard to stimuli-sensitive materials. In their Communication on page 4174 ff., K. Sada et al. demonstrate facile control of the LCST behavior of an organic polymer by manipulating the charge-transfer (CT) interactions between the polymer and an effector. The appearance of CT bands enables a quantitative evaluation of the thermodynamics of association.

    4. You have free access to this content
      Back Cover: A Tailor-Made Molecular Ruthenium Catalyst for the Oxidation of Water and Its Deactivation through Poisoning by Carbon Monoxide (Angew. Chem. Int. Ed. 15/2013) (page 4274)

      Dr. Markus D. Kärkäs, Dr. Torbjörn Åkermark, Hong Chen, Prof. Junliang Sun and Prof. Björn Åkermark

      Version of Record online: 20 MAR 2013 | DOI: 10.1002/anie.201301654

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      Two single-site ruthenium catalysts display a Janus-face-type behavior despite structural similarities. One complex is an efficient catalyst for the oxidation of water whereas the CO-containing complex, formed during catalysis, was found to be inactive. In their Communication on page 4189 ff., B. Åkermark and co-workers present a previously undiscovered deactivation pathway for ruthenium-based water-oxidation catalysts. Extensive studies were carried out to explain the diverse behavior in catalysis.

  2. Graphical Abstract

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

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

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. News
    5. Author Profile
    6. News
    7. Book Review
    8. Essay
    9. Minireview
    10. Review
    11. Communications
    1. Jaephil Cho (page 4066)

      Version of Record online: 28 NOV 2012 | DOI: 10.1002/anie.201208428

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      “My favorite saying is ,Just do it‘ When I was eighteen I wanted to be a detective …” This and more about Jaephil Cho can be found on page 4066.

  5. News

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

    1. Top of page
    2. Cover Pictures
    3. Graphical Abstract
    4. News
    5. Author Profile
    6. News
    7. Book Review
    8. Essay
    9. Minireview
    10. Review
    11. Communications
    1. Asymmetric Organocatalysis. Workbench Edition. 2 Volumes, Science of Synthesis Series. Edited by Benjamin List and Keiji Maruoka. (pages 4069–4070)

      Peter I. Dalko

      Version of Record online: 8 MAR 2013 | DOI: 10.1002/anie.201300113

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      Thieme, Stuttgart, 2012. 1928 pp., softcover, € 449.00.—ISBN 978-3131705914

  7. Essay

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

      Drug Discovery: A Modern Decathlon (pages 4072–4076)

      Prof. Dr. Stefan Laufer, Prof. Dr. Ulrike Holzgrabe and Prof. Dr. Dieter Steinhilber

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/anie.201210006

      The increasing costs as well as the lack of innovation potency in the development of new drugs have led to a discussion of the possible contribution of the German university landscape, especially pharmaceutical sciences. Successful examples are already apparent in the US.

  8. Minireview

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

      Strained Alkenes in Natural Product Synthesis (pages 4078–4087)

      Matthew R. Wilson and Dr. Richard E. Taylor

      Version of Record online: 28 FEB 2013 | DOI: 10.1002/anie.201207712

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      No strain, no gain: The high reactivity of strained alkenes facilitates complex synthetic transformations in a mild and atom-economical fashion. Recent developments in the synthesis and handling of distorted alkenes have led to the use of these highly reactive molecules as critical intermediates in natural product synthesis. The ability of strained alkenes to drive otherwise unfavorable reactions is demonstrated in a number of these examples.

  9. Review

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

      Protein Organic Chemistry and Applications for Labeling and Engineering in Live-Cell Systems (pages 4088–4106)

      Dr. Yousuke Takaoka, Prof. Dr. Akio Ojida and Prof. Dr. Itaru Hamachi

      Version of Record online: 20 FEB 2013 | DOI: 10.1002/anie.201207089

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      Labels of the reconstruction: Chemical modification of proteins with synthetic probes is a powerful means of elucidating protein functions in live cells and of influencing these functions. New reactions that can be successfully applied in living systems represent a worthy challenge to organic chemistry, especially as the labeling and manipulation of endogenous proteins in their natural habitats is currently at an early stage.

  10. Communications

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

      Formation of 1,3-Cyclohexanediones and Resorcinols Catalyzed by a Widely Occuring Ketosynthase (pages 4108–4112)

      Dipl.-Biol. Sebastian W. Fuchs, Dipl.-Bioinf. Kenan A. J. Bozhüyük, Dipl.-Bioinf. Darko Kresovic, Florian Grundmann, M. Sc. Veronica Dill, Dr. Alexander O. Brachmann, Dr. Nicholas R. Waterfield and Prof. Dr. Helge B. Bode

      Version of Record online: 19 FEB 2013 | DOI: 10.1002/anie.201210116

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      Overlooked, but widespread! A new class of ketosynthases (DarB) involved in the biosynthesis of 1,3-cyclohexanediones and dialkylresorcinols has been identified and characterized in detail. The presence of homologues in 89 different bacteria, including several pathogens, reveals that DarB as well as the corresponding natural products might be widespread, thus presenting a new but so far overlooked pathway to natural products.

    2. Stereoselective Catalysis

      Enantioselective Palladium-Catalyzed Decarboxylative Allylation of Carbazolones and Indolones: Formal Synthesis of (+)-Kopsihainanine A (pages 4113–4116)

      Christopher J. Gartshore and Dr. David W. Lupton

      Version of Record online: 30 JAN 2013 | DOI: 10.1002/anie.201209069

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      Adding value: A four-step synthesis of enantioenriched carbazolone and indolone derivatives has been developed using an enantioselective Pd-catalyzed decarboxylative allylation. The scope of this reaction is broad, and the materials are suited for natural product synthesis, shown with the completion of a formal synthesis of (+)-kopsihainanine (see scheme).

    3. Alkaloid Synthesis

      Enantioselective Palladium-Catalyzed Decarboxylative Allylation of Carbazolones: Total Synthesis of (−)-Aspidospermidine and (+)-Kopsihainanine A (pages 4117–4121)

      Zeqian Li, Shaoxiong Zhang, Shoutao Wu, Xiaolei Shen, Liwei Zou, Fengqun Wang, Xiang Li, Fangzhi Peng, Prof. Hongbin Zhang and Prof. Zhihui Shao

      Version of Record online: 8 MAR 2013 | DOI: 10.1002/anie.201209878

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      Functionalized chiral carbazolones with α-quaternary carbon centers are formed through the ligand-controlled Pd-catalyzed enantioselective decarboxylative allylic alkylation of carbazolones (see scheme). This catalytic asymmetric reaction was employed as the key step in the total synthesis of aspidospermidine and (+)-kopsihainanine A.

    4. Supramolecular Chirality

      Self-Assembly of Racemic Alanine Derivatives: Unexpected Chiral Twist and Enhanced Capacity for the Discrimination of Chiral Species (pages 4122–4126)

      Dr. Hai Cao, Dr. Xuefeng Zhu and Prof. Dr. Minghua Liu

      Version of Record online: 11 MAR 2013 | DOI: 10.1002/anie.201300444

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      Twisted ribbons were formed by the self-assembly of racemic alanine derivatives (middle picture), whereas only flat nanostructures were obtained from the individual enantiomers (left). The twist was sensitive to a slight enantiomeric excess and showed remarkable macroscopic chirality. Moreover, it could discriminate various amino acid derivatives (right) and even enabled the determination of the ee value of a mixed system.

    5. Drug Delivery

      Biodegradable ZnO@polymer Core–Shell Nanocarriers: pH-Triggered Release of Doxorubicin In Vitro (pages 4127–4131)

      Dr. Zheng-Yong Zhang, Yu-Dong Xu, Ying-Ying Ma, Li-Li Qiu, Dr. Yi Wang, Prof. Ji-Lie Kong and Prof. Huan-Ming Xiong

      Version of Record online: 5 MAR 2013 | DOI: 10.1002/anie.201300431

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      Luminescent ZnO@polymer core–shell nanoparticles were synthesized and loaded with doxorubicin (DOX) for the treatment of human brain cancer cells. Analyses by confocal laser scanning microscopy proved that the ZnO@polymer–DOX nanocomposites were decomposed at lysosomes to release DOX molecules, which penetrated into the nucleus and finally killed the cells (see picture).

    6. Click Chemistry

      Organocatalytic, Regioselective Nucleophilic “Click” Addition of Thiols to Propiolic Acid Esters for Polymer–Polymer Coupling (pages 4132–4136)

      Dr. Vinh X. Truong and Dr. Andrew P. Dove

      Version of Record online: 28 FEB 2013 | DOI: 10.1002/anie.201209239

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      Discerning Tastes: The regioselectivity of the nucleophilic addition of thiols to electron-deficient alkynes is controlled by the choice of the solvent (i.e. the polarity of the reaction mixture) and the catalyst. Both thioalkenes and dithianes can be prepared in a rapid reaction that generates no by-products (see scheme). In turn the utility of this reaction is shown for efficient end-group modification of polymers.

    7. Thin-Film Electrodes

      Catalytic Activity of Pt/TaB2(0001) for the Oxygen Reduction Reaction (pages 4137–4140)

      Eishiro Toyoda, Dr. Ryosuke Jinnouchi, Dr. Tetsu Ohsuna, Tatsuya Hatanaka, Dr. Takashi Aizawa, Dr. Shigeki Otani, Dr. Yoshiaki Kido and Dr. Yu Morimoto

      Version of Record online: 12 MAR 2013 | DOI: 10.1002/anie.201209413

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      A great film with special effects: An epitaxial Pt thin film with a thickness of 1.5 nm on a TaB2(0001) substrate (see high-angle annular dark-field STEM image) was tested as an electrocatalyst for the oxygen reduction reaction. Its specific activity was twice that observed for polycrystalline Pt or Pt(111). Analysis and DFT calculations showed that the Pt layer is alloyed with Ta, the electronic effect of which on Pt leads to the enhanced activity.

    8. Cancer Nanotechnology

      A Drug-Delivery Vehicle Combining the Targeting and Thermal Ablation of HER2+ Breast-Cancer Cells with Triggered Drug Release (pages 4141–4146)

      Prof. Dr. Jin-Oh You, Dr. Peng Guo and Prof. Dr. Debra T. Auguste

      Version of Record online: 11 MAR 2013 | DOI: 10.1002/anie.201209804

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      Covering all three bases: Drug-delivery vehicles that encapsulate doxorubicin (Dox) within a pH-sensitive matrix embedded with gold nanoparticles were synthesized with Herceptin–poly(ethylene glycol) conjugates on the surface for the specific binding of cancer cells (see picture; NIR=near infrared). Cell targeting was combined with enhanced cytotoxicity through triggered drug release (at pH 5–6) and thermal ablation (a photothermal effect).

    9. Peptidomimetics

      Controlling Helix Formation in the γ-Peptide Superfamily: Heterogeneous Foldamers with Urea/Amide and Urea/Carbamate Backbones (pages 4147–4151)

      Dr. Nagendar Pendem, Dr. Yella Reddy Nelli, Dr. Céline Douat, Dr. Lucile Fischer, Dr. Michel Laguerre, Dr. Eric Ennifar, Dr. Brice Kauffmann and Dr. Gilles Guichard

      Version of Record online: 4 MAR 2013 | DOI: 10.1002/anie.201209838

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      One fold to rule them all: New heterogeneous aliphatic backbone foldamers belonging to the γ-peptide superfamily and containing various combinations of urea/amide (U/A) and urea/carbamate (U/C) units are reported. Structural studies at atomic resolution reveal hydrogen-bonded helical structures akin to that formed by cognate Un homooligomers.

    10. NMR Spectroscopy

      Multiple Parallel 2D NMR Acquisitions in a Single Scan (pages 4152–4155)

      Dr. Kevin J. Donovan, Dr. Eriks Kupče and Prof. Lucio Frydman

      Version of Record online: 4 MAR 2013 | DOI: 10.1002/anie.201210070

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      Faster than ultrafast: A new sequence combining “ultrafast” single-shot 2D NMR and parallel receiving technologies is presented. The potential of the resulting parallel ultrafast 2D spectroscopy (PUFSY) NMR experiments is shown by simultaneously collecting homo- and heteronuclear correlation information for 1H–19F systems (see picture) and a 1H–31P system.

    11. Protein Dynamics

      Probing Slow Chemical Exchange at Carbonyl Sites in Proteins by Chemical Exchange Saturation Transfer NMR Spectroscopy (pages 4156–4159)

      Dr. Pramodh Vallurupalli and Prof. Lewis E. Kay

      Version of Record online: 28 FEB 2013 | DOI: 10.1002/anie.201209118

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      Seeing the invisible: A 13CO NMR chemical exchange saturation transfer (CEST) experiment for the study of “invisible” excited protein states with lifetimes on the order of 5–50 ms has been developed. The 13CO chemical shifts together with those obtained from fits of 15N CEST profiles establish that the A39G FF domain folds via a similar compact intermediate (I) as the wild-type protein (F and U=native and unfolded states).

    12. Organic–Inorganic Hybrid Composites

      Chemically Exfoliated MoS2 as Near-Infrared Photothermal Agents (pages 4160–4164)

      Stanley S. Chou, Dr. Bryan Kaehr, Jaemyung Kim, Brian M. Foley, Dr. Mrinmoy De, Prof. Patrick E. Hopkins, Prof. Jiaxing Huang, Prof. C. Jeffrey Brinker and Prof. Vinayak P. Dravid

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201209229

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      Two-dimensional bio-dynamite: Chemically exfoliated MoS2 (ceMoS2), a water-dispersible sheet-like material, is an efficient near-infrared (NIR) photothermal transducer. The superior bio-supramolecular properties of ceMoS2 and the ability of this material to destroy biomolecular targets through near-infrared (NIR) photothermal transduction were studied (see picture).

    13. Hierarchical Microstructures

      Self-Supported Construction of Uniform Fe3O4 Hollow Microspheres from Nanoplate Building Blocks (pages 4165–4168)

      Dr. Bao Wang, Hao Bin Wu, Dr. Lei Zhang and Prof. Xiong Wen (David) Lou

      Version of Record online: 13 MAR 2013 | DOI: 10.1002/anie.201300190

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      As alike as two peas in a pod: Hollow iron-containing microspheres composed of nanoplate-like building blocks were synthesized by a straightforward strategy and readily converted into magnetic Fe3O4 hollow microspheres (see images) without noticeable structural deformation. These Fe3O4 microspheres exhibited high reversible capacity and excellent cycling performance when evaluated as an anode material for lithium-ion batteries.

    14. Optofluidics

      A Plasmon-Assisted Optofluidic (PAOF) System for Measuring the Photothermal Conversion Efficiencies of Gold Nanostructures and Controlling an Electrical Switch (pages 4169–4173)

      Dr. Jie Zeng, David Goldfeld and Prof. Younan Xia

      Version of Record online: 12 MAR 2013 | DOI: 10.1002/anie.201210359

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      “Photothermometer”: A PAOF system was constructed using a diode laser as the energy source, an aqueous suspension of plasmonic nanostructures as the photothermal transducer, and a glass capillary for measuring the volumetric expansion of the suspension (see picture). The suspension could be driven to move up the capillary by more than 30 mm and be used to control the operation of an electrical switch.

    15. Thermoresponsive Polymers

      Polymer Phase-Transition Behavior Driven by a Charge-Transfer Interaction (pages 4174–4178)

      Shogo Amemori, Dr. Kenta Kokado and Prof. Dr. Kazuki Sada

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201210261

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      Cool down and get it together! The lower critical solution temperature (LCST) behavior of a polymer containing pyrene units was controlled by a charge-transfer (CT) interaction with an electron-accepting effector (see picture). The appearance of CT bands enabled quantitative evaluation of the thermodynamics of the association.

    16. Enzymatic Drug Release

      Physicochemical Properties of Protein-Coated Gold Nanoparticles in Biological Fluids and Cells before and after Proteolytic Digestion (pages 4179–4183)

      Dr. Munish Chanana, Dr. Pilar Rivera_Gil, Prof. Dr. Miguel A. Correa-Duarte, Prof. Dr. Luis M. Liz-Marzán and Prof. Dr. Wolfgang J. Parak

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201208019

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      What's going on in there?! Little is known about the fate of nanoparticles (NPs) after their internalization by cells and organisms. Protein-coated gold NPs were used to study the physicochemical properties of NPs in extra- and intracellular fluids. These potential vehicles for enzymatic drug delivery were highly stable at pH 7.4 in the presence of salts and free proteins, but agglomerated reversibly under acidic conditions (see picture).

    17. Polycycles

      Oxidative Cyclodimerization After Tandem Cyclization of Dehydrobenzo[14]annulenes Induced by Alkyllithium (pages 4184–4188)

      Shunpei Nobusue, Dr. Akihiro Shimizu, Prof. Kenji Hori, Dr. Ichiro Hisaki, Prof. Mikiji Miyata and Prof. Yoshito Tobe

      Version of Record online: 28 FEB 2013 | DOI: 10.1002/anie.201210233

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      After eight: Reactions of dehydrobenzo[14]annulenes induced by the addition of n-butyllithium led to the discovery of an unprecedented oxidative cyclodimerization, which forms eight-membered ring products in up to 30 % yield. The product contains two indeno[2,1-a]fluorene components connected by a single and a double bond, which result from three transannular bond formations.

    18. Oxidation of Water

      A Tailor-Made Molecular Ruthenium Catalyst for the Oxidation of Water and Its Deactivation through Poisoning by Carbon Monoxide (pages 4189–4193)

      Dr. Markus D. Kärkäs, Dr. Torbjörn Åkermark, Hong Chen, Prof. Junliang Sun and Prof. Björn Åkermark

      Version of Record online: 14 MAR 2013 | DOI: 10.1002/anie.201210226

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      No CO-operation: Two single-site ruthenium complexes, based on a tetradentate ligand, despite structural similarities, display a remarkable difference in their catalytic and chemical behavior (see picture). The fact that the CO-containing complex is formed in the catalytic oxidation of water suggests a novel pathway for the deactivation of ruthenium-based catalysts.

    19. Quinone Reduction

      You have full text access to this OnlineOpen article
      Reduction of Quinones by NADH Catalyzed by Organoiridium Complexes (pages 4194–4197)

      Dr. Zhe Liu, Prof.Dr. Robert J. Deeth, Jennifer S. Butler, Dr. Abraha Habtemariam, Prof. Dr. Mark E. Newton and Prof. Dr. Peter J. Sadler

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201300747

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      One electron at a time: Half-sandwich organometallic cyclopentadienyl–IrIII complexes containing N,N-chelated ligands can catalyze the reduction of quinones (Q), such as vitamin K3, to semiquinones (Q.−) by coenzyme NADH (see picture). DFT calculations suggest that the mechanism involves hydride transfer followed by two one-electron transfers and the unusual IrII oxidation state as a key transient intermediate.

    20. Rearrangements

      Gold-Catalyzed Rearrangement of Allylic Oxonium Ylides: Efficient Synthesis of Highly Functionalized Dihydrofuran-3-ones (pages 4198–4202)

      Junkai Fu, Dr. Hai Shang, Zhaofeng Wang, Dr. Le Chang, Wenbing Shao, Prof. Dr. Zhen Yang and Prof. Dr. Yefeng Tang

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/anie.201208305

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      “Diazo” not needed: The title reaction results in the rearrangement of oxonium ylides, which were prepared from readily available homopropargylic allylic ethers instead of diazo compounds, through two different mechanisms: a concerted 2,3-sigmatropic rearrangement, or a stepwise 1,4-allyl migration followed by a Claisen rearrangement (see scheme).

    21. Asymmetric Catalysis

      Cross-Metathesis/Iridium(I)-catalyzed Allylic Etherification Strategy: (Iterative) Catalytic Asymmetric Synthesis of syn- and anti-1,2-Diols (pages 4203–4206)

      Dr. Dongeun Kim, Dr. Jae Seung Lee, Prof. Dr. Suk Bin Kong and Prof. Dr. Hyunsoo Han

      Version of Record online: 15 JAN 2013 | DOI: 10.1002/anie.201209112

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      Protection optional: The title reaction strategy is used to prepare 1,2-diols with complete control of their absolute and relative stereochemistry. The method tolerates free and Me-/Bn-/TBS-protected alcohol functionalities, and its diastereoselectivity is controlled by the stereochemistry of the ligands/catalysts used. Protected 1,2,3,4-tetraols are synthesized by iterative applications of the strategy.

    22. Hydrogen-Bond-Promoted Palladium Catalysis: Allylic Alkylation of Indoles with Unsymmetrical 1,3-Disubstituted Allyl Acetates Using Chiral Bis(sulfoxide) Phosphine Ligands (pages 4207–4211)

      Dr. Le Du, Prof. Dr. Peng Cao, Dr. Junwei Xing, Yazhou Lou, Liyin Jiang, Dr. Liangchun Li and Prof. Dr. Jian Liao

      Version of Record online: 5 MAR 2013 | DOI: 10.1002/anie.201209485

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      A DYKAT die hard: A new class of chiral BiSO-P ligands were effective for an unprecedented palladium-catalyzed asymmetric allylic alkylation of indoles with the racemic title acetates through a dynamic kinetic asymmetric transformation (DYKAT). The hydrogen bond formed between the sulfinyl group of the ligand and NH of indole plays an important role in the reaction.

    23. Nanoribbons

      High-Quality Boron Nitride Nanoribbons: Unzipping during Nanotube Synthesis (pages 4212–4216)

      Ling Li, Dr. Lu Hua Li, Prof. Ying Chen, Dr. Xiujuan J. Dai, Dr. Peter R. Lamb, Dr. Bing-Ming Cheng, Meng-Yeh Lin and Prof. Xiaowei Liu

      Version of Record online: 4 MAR 2013 | DOI: 10.1002/anie.201209597

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      Zipper examined: High-quality boron nitride nanoribbons (BNNRs) can be produced directly during nanotube synthesis without post-treatment. These BNNRs are typically several micrometers long and tens of nanometers wide. Near-edge X-ray absorption fine structure investigations indicated that the BNNRs are of high chemical purity and crystallinity.

    24. Gold Nanoparticles

      Synthesis of Stable Peptide Nucleic Acid-Modified Gold Nanoparticles and their Assembly onto Gold Surfaces (pages 4217–4220)

      Philipp Anstaett, Dr. Yuanhui Zheng, Thibaut Thai, Dr. Alison M. Funston, Prof. Dr. Udo Bach and Prof. Dr. Gilles Gasser

      Version of Record online: 4 MAR 2013 | DOI: 10.1002/anie.201209684

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      PNA does it better: Peptide nucleic acid (PNA) oligomers were attached to gold nanoparticles (AuNPs) through a variety of mono- and trithiol linkers. These functionalized particles had sufficient stability for sequence-specific self-assembly onto gold surfaces (see figure) in the absence of ions or surfactants. The nanoparticle surface densities obtained were superior to comparable DNA-modified AuNPs.

    25. Biomimetic Synthesis

      Total Synthesis of Kingianins A, D, and F (pages 4221–4224)

      Samuel L. Drew, Dr. Andrew L. Lawrence and Prof. Michael S. Sherburn

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/anie.201210084

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      A synthesis fit for a king: The total synthesis of (±)-kingianins A, D, and F has been achieved in ten steps. Key features include the gram-scale synthesis and partial reduction of a conjugated tetrayne to a (Z,Z,Z,Z)-tetraene, the domino 8π–6π electrocyclic ring closure of a (Z,Z,Z,Z)-tetraene, and the radical-cation-catalyzed formal Diels–Alder dimerization of functionalized bicyclo[4.2.0]octadiene precursors.

    26. Photosynthesis

      Silicon Nanowires Show Improved Performance as Photocathode for Catalyzed Carbon Dioxide Photofixation (pages 4225–4228)

      Rui Liu, Carolynn Stephani, Jae Jin Han, Prof. Dr. Kian L. Tan and Prof. Dr. Dunwei Wang

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201210228

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      Wired: With silicon as a photocathode and [Ni(bpy)2] as a catalyst, visible light-powered CO2 photofixation is made possible (see picture). Owing to their multifaceted surfaces, silicon nanowires show a significantly better performance compared to planar Si. The shape of a nanowire is indeed an appealing materials choice for high-efficiency, low-cost solar energy conversion applications.

    27. Rearrangement

      Gold-Catalyzed Oxidative Cyclizations on 1,4-Enynes: Evidence for a γ-Substituent Effect on Wagner–Meerwein Rearrangements (pages 4229–4234)

      Satish Ghorpade, Prof. Dr. Ming-Der Su and Prof. Dr. Rai-Shung Liu

      Version of Record online: 5 MAR 2013 | DOI: 10.1002/anie.201210313

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      Gold-catalyzed oxidative cyclizations of 1,4-enynes were used to study the γ-effect on the Wagner–Meerwein rearrangement. Both experimental and theoretical work disclose that a gold substituent in the γ-position can direct a stereospecific 1,2-shift of the anti-β-substituent regardless of its intrinsic properties.

    28. Homogeneous Catalysis

      Design of Phosphorus Ligands with Deep Chiral Pockets: Practical Synthesis of Chiral β-Arylamines by Asymmetric Hydrogenation (pages 4235–4238)

      Dr. Guodu Liu, Xiangqian Liu, Zhihua Cai, Guangjun Jiao, Guangqing Xu and Prof. Dr. Wenjun Tang

      Version of Record online: 13 MAR 2013 | DOI: 10.1002/anie.201300646

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      WingPhos, a C2-symmetric bisphosphorus ligand with a deep and well-defined chiral pocket was developed. It has shown high efficiency in the rhodium-catalyzed asymmetric hydrogenation of (E)-β-aryl-N-acetyl enamides, cyclic β-aryl enamides, and heterocyclic β-aryl enamides. A series of chiral β-arylisopropylamines, 2-aminotetralines, and 3-aminochromans can be synthesized with excellent ee values (nbd=3,5-norbornadiene; TON=turnover number).

    29. Cyclization

      Construction of Eight-Membered Carbocycles through Gold Catalysis with Acetylene-Tethered Silyl Enol Ethers (pages 4239–4242)

      Dr. Tomohiro Iwai, Hiori Okochi, Dr. Hideto Ito and Prof. Dr. Masaya Sawamura

      Version of Record online: 4 MAR 2013 | DOI: 10.1002/anie.201300265

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      Semihollow triethynylphosphanes were synthesized and employed as ligands in the gold-catalyzed 8-exo-dig cyclization of acetylene-tethered silyl enol ethers to obtain eight-membered-ring carbocycles (see scheme). The gold–phosphane catalysts promoted either the annulation toward bicyclic structures or the cyclization of acyclic molecules to form nonfused carbocycles. Tf=Trifluoromethylsulfonyl.

    30. Transition States

      An Yttrium Hydride–Silane Complex as a Structural Model for a σ-Bond Metathesis Transition State (pages 4243–4246)

      Jiliang Zhou, Jiaxiang Chu, Yanyan Zhang, Guang Yang, Dr. Xuebing Leng and Prof. Dr. Yaofeng Chen

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201300638

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      A structural model for the transition state of the σ-bond metathesis between Si[BOND]H and M[BOND]E bonds (M: d0 transition metal) was obtained through the formation of an yttrium hydride–silane complex (see picture). The silane moiety can be either retained or released during the reactions of the complex with other substrates.

    31. Synthetic Methods

      Continuous-Flow Synthesis of 1-Substituted Benzotriazoles from Chloronitrobenzenes and Amines in a C[BOND]N Bond Formation/Hydrogenation/Diazotization/Cyclization Sequence (pages 4247–4250)

      Dr. Mao Chen and Prof. Dr. Stephen L. Buchwald

      Version of Record online: 1 MAR 2013 | DOI: 10.1002/anie.201300615

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      Two approaches have been developed for the regiospecific continuous-flow synthesis of 1-substituted benzotriazoles. They begin with either an SNAr reaction at high temperature or Pd catalysis and involve consecutive multiphase processes, allowing the multistep synthesis of benzotriazoles to take place in an efficient manner (see picture).

    32. Synthetic Peptides

      Peptide Fragment Coupling Using a Continuous-Flow Photochemical Rearrangement of Nitrones (pages 4251–4255)

      Dr. Yuan Zhang, Dr. Melissa L. Blackman, Dr. Andrew B. Leduc and Prof. Dr. Timothy F. Jamison

      Version of Record online: 4 MAR 2013 | DOI: 10.1002/anie.201300504

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      Go with the flow: A general approach for amide bond formation by way of a continuous-flow photochemical rearrangement of nitrones was described (see scheme). Simple aryl-alkyl amide bonds as well as complex peptide bonds were constructed efficiently with a residence time less than 20 minutes. A tetrapeptide was synthesized in this way and the method could be applied to peptide fragment coupling.

    33. Frustrated Lewis Pairs

      Reaction of a P/Al-Based Frustrated Lewis Pair with Ammonia, Borane, and Amine–Boranes: Adduct Formation and Catalytic Dehydrogenation (pages 4256–4259)

      Dr. Christian Appelt, Dr. J. Chris Slootweg, Prof. Dr. Koop Lammertsma and Prof. Dr. Werner Uhl

      Version of Record online: 7 MAR 2013 | DOI: 10.1002/anie.201208746

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      Open wide! The geminal P/Al-based frustrated Lewis pair (Mes2P)(tBu2Al)C[DOUBLE BOND]C(H)Ph forms stable Lewis adducts with BH3 and NH3. This compound facilitates the dehydrocoupling of the ammonia–borane adduct by unusual N[BOND]H bond activation and elimination of dihydrogen at the boron center, and it is a very active main-group-based FLP catalyst for the dehydrogenation of amine–borane H3B⋅NMe2H. Mes=mesityl.

    34. Protein Chemistry

      Chemical Bypass of Intein-Catalyzed N–S Acyl Shift in Protein Splicing (pages 4260–4264)

      Dr. Jens Binschik and Prof. Dr. Henning D. Mootz

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/anie.201208863

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      Spliced: An N-methyl group was introduced at the scissile peptide bond in a semisynthetic intein precursor. With the chemical modification, thioester formation and protein splicing was observed in the absence of the otherwise critical block B histidine. This finding shows the role of the histidine in ground-state destabilization and rules out other previously proposed roles for this residue in the protein splicing pathway.

    35. Chemical Glycobiology

      Two-Color Glycan Labeling of Live Cells by a Combination of Diels–Alder and Click Chemistry (pages 4265–4268)

      Dipl.-Chem. Andrea Niederwieser, M. Sc. Anne-Katrin Späte, Dr. Long Duc Nguyen, M. Sc. Christian Jüngst, Prof. Dr. Werner Reutter and Prof. Dr. Valentin Wittmann

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/anie.201208991

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      One is not enough: Terminal alkenes are used as chemical reporters and ligation partners for 1,2,4,5-tetrazines in a Diels–Alder reaction with inverse electron demand (DARinv). Combination with strain-promoted azide–alkyne cycloaddition (SPAAC) allows the visualization of two different glycan structures in one experiment.

    36. Stable DNA

      Protection and Deprotection of DNA—High-Temperature Stability of Nucleic Acid Barcodes for Polymer Labeling (pages 4269–4272)

      M. Sc. Daniela Paunescu, Dr. Roland Fuhrer and Dr. Robert N. Grass

      Version of Record online: 6 MAR 2013 | DOI: 10.1002/anie.201208135

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      Tough to remove this label! When protected within a silica sphere, DNA can withstand high temperatures (up to 200 °C) and aggressive radical conditions. Following deprotection with HF, the DNA can be analyzed by standard biochemical methods. This DNA protection/deprotection scheme is compatible with standard polymer processing and can be used for labeling material of nonbiological origin.

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