Angewandte Chemie International Edition

Cover image for Vol. 49 Issue 12

March 15, 2010

Volume 49, Issue 12

Pages 2069–2255

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. Cover Picture: Enantioselective Kita Oxidative Spirolactonization Catalyzed by In Situ Generated Chiral Hypervalent Iodine(III) Species (Angew. Chem. Int. Ed. 12/2010) (page 2069)

      Muhammet Uyanik, Takeshi Yasui and Kazuaki Ishihara

      Version of Record online: 1 MAR 2010 | DOI: 10.1002/anie.201000768

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      Conformationally flexibleC2-symmetric chiral iodosylarene, which has been rationally designed based on secondary n–σ* or hydrogen-bonding interactions, is a highly effective catalyst for the Kita oxidative spirolactonization. As described by K. Ishihara and co-workers in their Communication on page 2175 ff., this catalysis provides the highest enantioselectivity (up to 92 % ee) among previous chiral hypervalent iodine-catalyzed reactions.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. Inside Cover: Nucleophilic Phosphinidene Complexes: Access and Applicability (Angew. Chem. Int. Ed. 12/2010) (page 2070)

      Halil Aktaş, J. Chris Slootweg and Koop Lammertsma

      Version of Record online: 23 FEB 2010 | DOI: 10.1002/anie.201000370

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      Nucleophilic phosphinidene complexes, which are isoelectronic to well-known carbene complexes, are establishing themselves as useful reagents for organic synthesis. In their Minireview on page 2102 ff., K. Lammertsma et al. give an overview of the different synthetic pathways to this class of phosphorus reagents and describe their potential applications for a wide range of chemical conversions.

  3. Graphical Abstract

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

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. You have free access to this content
      Super High Threshold Percolative Ferroelectric/Ferrimagnetic Composite Ceramics with Outstanding Permittivity and Initial Permeability (page 2083)

      Hui Zheng, Yanling Dong, Xin Wang, Wenjian Weng, Gaorong Han, Ning Ma and Piyi Du

      Version of Record online: 10 MAR 2010 | DOI: 10.1002/anie.201090032

      This article corrects:
    2. You have free access to this content
      A Formal Carbon–Sulfur Triple Bond: H[BOND]C[TRIPLE BOND]S[BOND]O[BOND]H (page 2083)

      Peter R. Schreiner, Hans Peter Reisenauer, Jaroslaw Romanski and Grzegorz Mloston

      Version of Record online: 10 MAR 2010 | DOI: 10.1002/anie.201090035

      This article corrects:

      A Formal Carbon–Sulfur Triple Bond: H[BOND]C[TRIPLE BOND]S[BOND]O[BOND]H1

      Vol. 48, Issue 43, 8133–8136, Version of Record online: 19 SEP 2009

  5. News

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

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. Horst Kunz (pages 2092–2094)

      Version of Record online: 2 MAR 2010 | DOI: 10.1002/anie.201000718

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      “My favorite piece of research is to simulate and elucidate processes of biological regulation through structurally specified models. The part of my job which I enjoy the most is that ideas can be proven by experiments …” This and more about Horst Kunz can be found on page 2092.

  7. Book Review

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. Synthesis of Solid Catalysts. Edited by Krijn P. de Jong. (page 2095)

      Malte Behrens

      Version of Record online: 10 MAR 2010 | DOI: 10.1002/anie.200907333

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      Wiley-VCH, Weinheim 2009. 402 pp., hardcover € 139.00.—ISBN 978-3527320400

  8. Highlights

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. C[BOND]H Activation

      Formal Inverse Sonogashira Reaction: Direct Alkynylation of Arenes and Heterocycles with Alkynyl Halides (pages 2096–2098)

      Alexander S. Dudnik and Vladimir Gevorgyan

      Version of Record online: 28 FEB 2010 | DOI: 10.1002/anie.200906755

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      Getting straight to the point: Recent developments in the direct functionalization of unreactive C[BOND]H bonds have established the title reaction (see scheme). Various main-group (M) and transition metals (TM) serve as efficient promoters or catalysts for this transformation.

    2. Bioinorganic Chemistry

      A Biomimetic Ferric Hydroperoxo Porphyrin Intermediate (pages 2099–2101)

      Sam P. de Visser, Joan Selverstone Valentine and Wonwoo Nam

      Version of Record online: 5 FEB 2010 | DOI: 10.1002/anie.200906736

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      OOH, my! The protonation of a side-on high-spin ferric peroxo species yields the corresponding end-on low-spin ferric hydroperoxo intermediate (see picture), which is a precursor of Compound I and has been frequently proposed as a reactive species in heme enzymes. This ferric hydroperoxo complex can be used to study reactivities of similar species in substrate oxygenation and hydroperoxide O[BOND]O bond cleavage reactions.

  9. Minireview

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

      Nucleophilic Phosphinidene Complexes: Access and Applicability (pages 2102–2113)

      Halil Aktaş, J. Chris Slootweg and Koop Lammertsma

      Version of Record online: 15 FEB 2010 | DOI: 10.1002/anie.200905689

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      Make it and break it! An overview of the different methodologies to synthesize nucleophilic phosphinidene complexes is presented. The emerging applicability of this class of phosphorus reagents as phosphinidene transfer agents that also posses the established reactivity of the isoelectronic metal-complexed carbenes makes them viable synthetic targets for a broad spectrum of chemical conversions.

  10. Review

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. Biosensors and Carbon Nanomaterials

      Carbon Nanomaterials in Biosensors: Should You Use Nanotubes or Graphene? (pages 2114–2138)

      Wenrong Yang, Kyle R. Ratinac, Simon P. Ringer, Pall Thordarson, J. Justin Gooding and Filip Braet

      Version of Record online: 24 FEB 2010 | DOI: 10.1002/anie.200903463

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      Coiled or unrolled? Many research groups are working to incorporate carbon nanotubes or graphene into prototype biosensors (see picture). This Review critically explores the latest advances in electrochemical, electrical, and optical biosensors that use carbon nanotubes and graphene, and compares the biosensing performance of these unique allotropes of carbon.

  11. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigenda
    6. News
    7. Author Profile
    8. Book Review
    9. Highlights
    10. Minireview
    11. Review
    12. Communications
    13. Preview
    1. Hybrid Composites

      Biologically Inspired, Strong, Transparent, and Functional Layered Organic–Inorganic Hybrid Films (pages 2140–2145)

      Hong-Bin Yao, Hai-Yu Fang, Zhi-Hua Tan, Li-Heng Wu and Shu-Hong Yu

      Version of Record online: 24 FEB 2010 | DOI: 10.1002/anie.200906920

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      Like mother nature: Biologically inspired organic–inorganic hybrid films comprising alternating layers of chitosan and micro- and nanoplatelets of layered double hydroxides mimic the unique layered microstructures of seashell nacre (see picture) and display high tensile strength. Moreover, the hybrid films can be endowed with the optical properties of the platelets.

    2. Lithium Batteries

      A Critical Size of Silicon Nano-Anodes for Lithium Rechargeable Batteries (pages 2146–2149)

      Hyejung Kim, Minho Seo, Mi-Hee Park and Jaephil Cho

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/anie.200906287

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      Well-dispersed Si nanocrystals with sizes of approximately 5, 10, and 20 nm were prepared in reverse micelles at high pressure and 380 °C and investigated as anode materials for lithium batteries. The 10 nm sized nanocrystals show a first charge capacity y of 3380 mAh g−1 and the highest capacity retention of 81 % after 40 cycles, which can be increased to 96 % by carbon coating (see picture).

    3. Biosensors

      An In Vivo Fluorescent Sensor Reveals Intracellular Ins(1,3,4,5)P4 Dynamics in Single Cells (pages 2150–2153)

      Reiko Sakaguchi, Kazuki Tainaka, Naoko Shimada, Shun Nakano, Masafumi Inoue, Shigeki Kiyonaka, Yasuo Mori and Takashi Morii

      Version of Record online: 7 NOV 2009 | DOI: 10.1002/anie.200903951

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      Don′t shoot the messenger! An optical sensor for D-myo-inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4), an intracellular second messenger, is constructed by introducing a fluorophore at a unique cysteine residue within a mutant of the pleckstrin homology (PH) domain of the general receptor for phosphoinositides 1 (GRP1). The biosensor visualizes the Ins(1,3,4,5)P4 dynamics by agonist stimulation in single live cells.

    4. Graphene Sensors

      All-Organic Vapor Sensor Using Inkjet-Printed Reduced Graphene Oxide (pages 2154–2157)

      Vineet Dua, Sumedh P. Surwade, Srikanth Ammu, Srikanth Rao Agnihotra, Sujit Jain, Kyle E. Roberts, Sungjin Park, Rodney S. Ruoff and Sanjeev K. Manohar

      Version of Record online: 24 FEB 2010 | DOI: 10.1002/anie.200905089

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      Flexisense: Films of graphene oxide and reduced graphene oxide are printed onto a flexible plastic surface (see picture), using inkjet techniques, which are used to detect chemically aggressive vapors such as NO2 and Cl2. Vapors in the 100 ppm–500 ppb concentration range can be detected in an air sample without the aid of a vapor concentrator.

    5. Bacteria in Nonaqueous Solution

      Bacteria Incorporation in Deep-eutectic Solvents through Freeze-Drying (pages 2158–2162)

      María C. Gutiérrez, María L. Ferrer, Luís Yuste, Fernando Rojo and Francisco del Monte

      Version of Record online: 26 NOV 2009 | DOI: 10.1002/anie.200905212

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      Taking fish out of water: Freeze-drying can be used to incorporate bacteria in a deep-eutectic solvent with outstanding preservation of integrity and viability. (Intact E. coli are marked by arrows in the image.) These findings open interesting perspectives for the use of whole microorganisms in biocatalytic processes carried out in nonaqueous solvents.

    6. Emulsions

      Inversion of Particle-Stabilized Emulsions to Form High-Internal-Phase Emulsions (pages 2163–2166)

      Guanqing Sun, Zifu Li and To Ngai

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/anie.200907175

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      Two triggers: Phase inversion of a particle-stabilized oil–water system from an ordinary oil-in-water emulsion (see picture, left; green: oil, pink: water) to a water-in-oil high-internal-phase emulsion (right) at a fixed oil/water ratio (27:73 vol %) can be simply driven by either a change of pH value or salt concentration in a single system. Scale bars: 30 μm.

      Corrected by:

      Corrigendum: Corrigendum: Inversion of Particle-Stabilized Emulsions to Form High-Internal-Phase Emulsions

      Vol. 49, Issue 45, 8295, Version of Record online: 29 OCT 2010

    7. DNAzymes

      A Light-Driven DNA Nanomachine for the Efficient Photoswitching of RNA Digestion (pages 2167–2170)

      Mengguang Zhou, Xingguo Liang, Toshio Mochizuki and Hiroyuki Asanuma

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/anie.200907082

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      Photons as fuel: A photoresponsive DNA enzyme was constructed that can work at the single-molecule level. Complete ON–OFF photoswitching of RNA digestion was realized by photoregulating the topological structure of a DNAzyme/RNA complex. The key components of the photoswitch are azobenzene units.

    8. Nanotechnology

      Erasable Nanoporous Antireflection Coatings Based on the Reconstruction Effect of Layered Double Hydroxides (pages 2171–2174)

      Jingbin Han, Yibo Dou, Min Wei, David G. Evans and Xue Duan

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/anie.200907005

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      Eraserhead: A reversible nanoporous antireflection coating can be fabricated by assembly of layered double hydroxide nanoparticles with polyanions using an electrostatic layer-by-layer method followed by calcination. Antireflection properties of the coating can be switched between the porous and non-porous state by alternating calcination and rehydration processes.

    9. Hypervalent Compounds

      Enantioselective Kita Oxidative Spirolactonization Catalyzed by In Situ Generated Chiral Hypervalent Iodine(III) Species (pages 2175–2177)

      Muhammet Uyanik, Takeshi Yasui and Kazuaki Ishihara

      Version of Record online: 1 MAR 2010 | DOI: 10.1002/anie.200907352

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      The iodines(III) have it: The rational design of a conformationally flexible C2-symmetric iodosylarene catalyst has been used for the enantioselective Kita oxidative spirolactonization. The reaction occurs through secondary n–σ* or hydrogen-bonding interactions between the chiral catalyst and the substrate. Mes=mesityl (2,4,6-trimethylphenyl).

    10. Guanidines

      Radical Synthesis of Guanidines from N-Acyl Cyanamides (pages 2178–2181)

      Marie-Hélène Larraufie, Cyril Ollivier, Louis Fensterbank, Max Malacria and Emmanuel Lacôte

      Version of Record online: 24 FEB 2010 | DOI: 10.1002/anie.200907237

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      Center stage: Additions of nitrogen-centered radicals to cyanamide compounds provided the first radical synthesis of aromatic polycyclic guanidine derivatives (see scheme). Modular assembly of the substrates allows for a rapid increase of the molecular complexity of scaffolds, which have potential applications for medicinal chemistry.

    11. Chiral Imines

      Enantioselective Biocatalytic Oxidative Desymmetrization of Substituted Pyrrolidines (pages 2182–2184)

      Valentin Köhler, Kevin R. Bailey, Anass Znabet, James Raftery, Madeleine Helliwell and Nicholas J. Turner

      Version of Record online: 9 FEB 2010 | DOI: 10.1002/anie.200906655

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      Made up out of air: The highly enantioselective oxidation of 3,4-substituted meso-pyrrolidines to Δ1-pyrrolines is reported. The reaction is catalyzed by monoamine oxidase from Aspergillus niger (MAO-N D5) and utilizes molecular oxygen from air as the stoichiometric oxidant. The corresponding Δ1-pyrrolines serve as useful building blocks for the synthesis of L-proline analogues and α-amino nitriles of high enantiomeric purity.

    12. Cross-Coupling

      Copper(I) Phenoxide Complexes in the Etherification of Aryl Halides (pages 2185–2189)

      Jesse W. Tye, Zhiqiang Weng, Ramesh Giri and John F. Hartwig

      Version of Record online: 2 MAR 2010 | DOI: 10.1002/anie.200902245

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      No copping out! Copper(I) phenoxide complexes containing chelating ligands (see picture), proposed intermediates in copper-catalyzed etherification of aryl halides, have been synthesized and fully characterized. The kinetic and chemical competence of the isolated complexes are demonstrated for the synthesis of aryl phenyl ethers, and experiments provide evidence against mechanistic pathways involving the formation of either free or caged radicals.

    13. Multicomponent Reactions

      Cooperative Catalysis in Multicomponent Reactions: Highly Enantioselective Synthesis of γ-Hydroxyketones with a Quaternary Carbon Stereocenter (pages 2190–2192)

      Xiao-Yu Guan, Li-Ping Yang and Wenhao Hu

      Version of Record online: 5 NOV 2009 | DOI: 10.1002/anie.200904905

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      Together they make a difference: An aryl diazoacetate, H2O, and an α,β-unsaturated 2-acyl imidazole give γ-hydroxyketones with a quaternary carbon stereocenter with excellent selectivity only if all three catalyst components shown in the scheme are present. The Michael addition step did not occur when a similar reagent mixture was treated with the [Rh2(OAc)4] catalyst alone. OTf=triflate, Ts=p-tosyl.

    14. Ultrasoft Colloids

      Microgel Translocation through Pores under Confinement (pages 2193–2197)

      Grant R. Hendrickson and L. Andrew Lyon

      Version of Record online: 22 FEB 2010 | DOI: 10.1002/anie.200906606

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      Tight fit: Hydrogel microparticles can conform to and pass through pores up to 10 times smaller than the particle diameter (see picture). Network flexibility of this extent is unprecedented in the context of pore passage. Microgels even show such compressibility and prepenetration at size ratios and pressure differentials comparable to physiological renal filtration conditions, making them of potential interest in drug-delivery applications.

    15. Carbenes

      Non-Innocent Behavior of a Tridentate NHC Chelating Ligand Coordinated onto a Zirconium(IV) Center (pages 2198–2201)

      Charles Romain, Karinne Miqueu, Jean-Marc Sotiropoulos, Stéphane Bellemin-Laponnaz and Samuel Dagorne

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/anie.200906702

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      NHC me, now you don′t: A tridentate bis(aryloxide)NHC-chelating ligand readily coordinates to ZrIV and undergoes an unprecedented THF-promoted benzyl migration from the zirconium metal center to the Ccarbene atom of the NHC. NHC=N-heterocyclic carbene.

    16. C[BOND]H Functionalization

      Nickel-Catalyzed Direct C[BOND]H Arylation and Alkenylation of Heteroarenes with Organosilicon Reagents (pages 2202–2205)

      Hitoshi Hachiya, Koji Hirano, Tetsuya Satoh and Masahiro Miura

      Version of Record online: 24 FEB 2010 | DOI: 10.1002/anie.200906996

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      Breaking the Si-lence: The direct cross-coupling of heteroarenes with aryl- or alkenylsilanes proceeds efficiently, in the presence of a nickel catalyst, to create a wide range of aryl–and alkenyl–heteroaryl bonds efficiently (see scheme; DMAc=N,N-dimethylacetamide, bpy=2,2′-bipyridine). This catalysis represents a new avenue for using organosilanes in the catalytic C[BOND]H functionalization chemistry.

    17. [5+2] Cycloaddition

      Rhodium(I)-Catalyzed Intramolecular [5+2] Cycloaddition Reactions of Alkynes and Allenylcyclopropanes: Construction of Bicyclo[5.4.0]undecatrienes and Bicyclo[5.5.0]dodecatrienes (pages 2206–2210)

      Fuyuhiko Inagaki, Katsuya Sugikubo, Yusuke Miyashita and Chisato Mukai

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/anie.200906994

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      Come on allene: The [{RhCl(CO)2}2]- or [{RhCl(CO)dppp}2]-catalyzed intramolecular [5+2] cycloaddition of alkyne-allenylcyclopropanes under mild conditions affords the bicyclo[5.4.0]undecatriene or the larger bicyclo[5.5.0]dodecatriene frameworks (see scheme; dppp=1,3-bis(diphenylphosphino)propane).

    18. Nanoparticle Catalysts

      Electrostatic Self-Assembly of a Pt-around-Au Nanocomposite with High Activity towards Formic Acid Oxidation (pages 2211–2214)

      Sheng Zhang, Yuyan Shao, Geping Yin and Yuehe Lin

      Version of Record online: 23 FEB 2010 | DOI: 10.1002/anie.200906987

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      Opposites attract: A Pt-around-Au nanocomposite is synthesized by electrostatic self-assembly (see picture; PDDA=poly(diallyldimethylammonium chloride)). This catalyst shows significantly improved activity towards formic acid oxidation versus pure Pt catalysts. The possible reason is the efficient spillover of HCOO from Au to the surrounding Pt nanoparticles, where HCOO is further oxidized to CO2.

    19. Electrophilic Fluorination

      Convenient Electrophilic Fluorination of Functionalized Aryl and Heteroaryl Magnesium Reagents (pages 2215–2218)

      Shigeyuki Yamada, Andrei Gavryushin and Paul Knochel

      Version of Record online: 16 FEB 2010 | DOI: 10.1002/anie.200905052

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      Give me an “F”: Electrophilic fluorination of various aromatic and heteroaromatic Grignard reagents is smoothly performed with (PhSO2)2NF as fluorinating agent in a 4:1 mixture of CH2Cl2/perfluorodecalin (see scheme). This solvent system allows minimization of most side reactions.

    20. Selective Fluorination

      Efficient Synthesis of Aryl Fluorides (pages 2219–2222)

      Pazhamalai Anbarasan, Helfried Neumann and Matthias Beller

      Version of Record online: 10 DEC 2009 | DOI: 10.1002/anie.200905855

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      Creating C[BOND]F bonds: A novel electrophilic fluorination of aryl and heteroaryl Grignard reagents has been discovered and was used for the efficient synthesis of various aryl fluoride derivatives (see picture; THF=tetrahydrofuran).

    21. Kinetic Resolution

      Catalytic Asymmetric Si[BOND]O Coupling of Simple Achiral Silanes and Chiral Donor-Functionalized Alcohols (pages 2223–2226)

      Andreas Weickgenannt, Marius Mewald, Thomas W. T. Muesmann and Martin Oestreich

      Version of Record online: 3 DEC 2009 | DOI: 10.1002/anie.200905561

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      Silicon alley: Si[BOND]H and H[BOND]OR are enantioselectively coupled in the presence of a chiral Cu[BOND]H complex. In this way, the kinetic resolution of racemic mixtures of alcohols is accomplished through asymmetric protection with standard silanes (see scheme; R=aryl or alkyl, Ar=3,5-xylyl, Np=2-naphthyl; s=selectivity factor).

    22. Imaging Agents

      Targeted LipoCEST Contrast Agents for Magnetic Resonance Imaging: Alignment of Aspherical Liposomes on a Capillary Surface (pages 2227–2229)

      Dirk Burdinski, Jeroen A. Pikkemaat, Mustafa Emrullahoglu, Francesca Costantini, Willem Verboom, Sander Langereis, Holger Grüll and Jurriaan Huskens

      Version of Record online: 12 FEB 2010 | DOI: 10.1002/anie.200905731

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      Searching for orientation: The alignment of aspherical paramagnetic liposomes in a magnetic field makes them attractive contrast agents for magnetic resonance (MR) imaging. The orientation of aspherical liposomes in solution, and the orientation change upon binding to a target surface was determined by using a simple MR technique (see picture).

    23. Femtochemistry in Ionic Liquids

      12′-Apo-β-caroten-12′-al: An Ultrafast “Spy” Molecule for Probing Local Interactions in Ionic Liquids (pages 2230–2232)

      Kawon Oum, Peter W. Lohse, Florian Ehlers, Mirko Scholz, Matthäus Kopczynski and Thomas Lenzer

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/anie.200906046

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      Superquick espionage: Attaching an aldehyde function to a simple carotenoid generates a powerful laser spectroscopy probe for elucidating solvation dynamics and polarity in ionic liquids with ultrafast pump–supercontinuum-probe broadband absorption spectroscopy.

    24. Water Oxidation

      Calcium Manganese(III) Oxides (CaMn2O4x H2O) as Biomimetic Oxygen-Evolving Catalysts (pages 2233–2237)

      Mohammad Mahdi Najafpour, Till Ehrenberg, Mathias Wiechen and Philipp Kurz

      Version of Record online: 22 FEB 2010 | DOI: 10.1002/anie.200906745

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      Biomimetic and efficient: Mixed calcium manganese(III) oxides (see structure; Ca green, Mn red, O white) with elemental compositions and structures mimicking the active site of photosystem II were found to be highly active catalysts for the oxidation of water to molecular oxygen. As for PS II, the presence of Ca2+ greatly enhances the catalyst performance in comparison to the related manganese-only system Mn2O3.

    25. Bioanalytical Chemistry

      Optical Thermophoresis for Quantifying the Buffer Dependence of Aptamer Binding (pages 2238–2241)

      Philipp Baaske, Christoph J. Wienken, Philipp Reineck, Stefan Duhr and Dieter Braun

      Version of Record online: 23 FEB 2010 | DOI: 10.1002/anie.200903998

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      Some like it hot: A robust and fast method for characterizing aptamers relies on the distinct thermophoretic movements of molecules in microscopic temperature gradients (see diagram). The binding properties of proteins and even small molecules can be measured within seconds, and less than 1 μL of sample is required. Notably, the technique works well in complex liquids such as human serum.

    26. Agostic Interactions

      On the Nature of Agostic Interactions in Transition-Metal Amido Complexes (pages 2242–2246)

      Wolfgang Scherer, David J. Wolstenholme, Verena Herz, Georg Eickerling, Andreas Brück, Paul Benndorf and Peter W. Roesky

      Version of Record online: 24 FEB 2010 | DOI: 10.1002/anie.200905463

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      Not the same: β-H elimination in alkyl species containing a β-agostic interactions (see picture, right) is facilitated by negative hyperconjugative delocalization of the M[BOND]C bonding electron pair over the alkyl backbone. This process is significantly hindered by the π character of the M[BOND]N bond in corresponding amido complexes with agostic interactions (left). Hence, both types of agostic interactions should be discriminated from one another.

    27. Chiral Oligomers

      Amplification of Chirality in Monodisperse, Enantiopure Alleno-Acetylenic Oligomers (pages 2247–2250)

      Pablo Rivera-Fuentes, José Lorenzo Alonso-Gómez, Ana G. Petrovic, Fabrizio Santoro, Nobuyuki Harada, Nina Berova and François Diederich

      Version of Record online: 27 JAN 2010 | DOI: 10.1002/anie.200906191

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      Enantiomerically pure alleno-acetylenic oligomers of defined lengths were synthesized by the palladium-mediated oxidative homocoupling of optically pure 1,3-diethynylallenes. The large amplification of their chiroptical properties strongly suggests the formation of helical secondary structures. This assignment is supported by time-dependent quantum chemical calculations.

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