Angewandte Chemie International Edition

Cover image for Vol. 46 Issue 34

August 27, 2007

Volume 46, Issue 34

Pages 6381–6557

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Cover Picture: Ruthenium-Catalyzed Enantioselective Propargylation of Aromatic Compounds with Propargylic Alcohols via Allenylidene Intermediates (Angew. Chem. Int. Ed. 34/2007) (page 6381)

      Hiroshi Matsuzawa, Yoshihiro Miyake and Yoshiaki Nishibayashi

      Version of Record online: 20 AUG 2007 | DOI: 10.1002/anie.200790166

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      Ruthenium-catalyzed enantioselective propargylation of aromatic compounds, such as furans and N,N-dimethylaniline, with propargylic alcohols afforded the corresponding propargylated aromatic compounds, as the first example of asymmetric propargylation of aromatic compounds. In their Communication on page 6488 ff., Y. Nishibayashi et al. develop the method to provide a novel asymmetric Friedel–Crafts alkylation of aromatic compounds by using propargylic alcohols as a new type of electrophile.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
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    1. Inside Cover: Amplified Chiral Transformation through Helical Assembly (Angew. Chem. Int. Ed. 34/2007) (page 6382)

      Kunihiko Toyofuku, Md. Akhtarul Alam, Akihiko Tsuda, Norifumi Fujita, Shigeru Sakamoto, Kentaro Yamaguchi and Takuzo Aida

      Version of Record online: 20 AUG 2007 | DOI: 10.1002/anie.200790167

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      “Chiral amplification” by temporal conversion of a substrate into a helical polymeric precursor, in which the handedness is determined by the ‘majority rule’, is described by T. Aida and co-workers in their Communication on page 6476 ff. The basic strategy, which is demonstrated by the asymmetric transformation of a chirality-memorizing D2-symmetric saddle-shaped porphyrin, may give a new rationale for general asymmetric synthesis.

  3. Graphical Abstract

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    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
    11. Preview
  4. News

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

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

    1. Top of page
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    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
    8. Minireview
    9. Review
    10. Communications
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    1. When Single-Site Polymerization Catalysis Meets Chirality: Optical Activity of Stereoregular Polyolefins (pages 6404–6406)

      Jean-François Carpentier

      Version of Record online: 31 JUL 2007 | DOI: 10.1002/anie.200701664

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      Ziegler–Natta revival: Enantiomerically pure, isotactic oligo/polystyrenes have been prepared by titanium-based single-site catalysis. The optical activity of these polystyrenes was shown to be measurable up to a degree of polymerization of 45, providing a discrete border for the appearance of “cryptochirality” for larger macromolecules. MAO=methylaluminoxane.

  7. Minireview

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    1. Electronic Aptamer-Based Sensors (pages 6408–6418)

      Itamar Willner and Maya Zayats

      Version of Record online: 28 JUN 2007 | DOI: 10.1002/anie.200604524

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      How apt these sensors are! Electronic aptamer-based sensors (aptasensors) hold great promise as analytical devices for the detection of low-molecular-weight substrates or proteins. The Minireview highlights the advantages of electronic transduction of aptasensor systems and discusses the latest developments in the design of electrochemical, field-effect transistor, and piezoelectric aptasensor systems.

  8. Review

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    1. Forty Years of In Vitro Evolution (pages 6420–6436)

      Gerald F. Joyce

      Version of Record online: 16 JUL 2007 | DOI: 10.1002/anie.200701369

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      Darwinian chemistry was first practiced by Spiegelman and colleagues in 1967 when they carried out the Darwinian evolution of RNA molecules in a test tube. In the following 40 years, the directed evolution of RNA has become a highly fruitful area of research and has deepened our understanding of evolutionary processes at the molecular level.

  9. Communications

    1. Top of page
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    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlight
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    9. Review
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    1. Unprecedented Tetranuclear Complexes with 20-Electron NiII Centers: The Role of Pressure and Temperature on Their Solid-State and Solution Fragmentation (pages 6438–6441)

      Anthony Kermagoret, Roberto Pattacini, Patricia Chavez Vasquez, Guillaume Rogez, Richard Welter and Pierre Braunstein

      Version of Record online: 16 JUL 2007 | DOI: 10.1002/anie.200701483

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      Complexes under pressure! The complexes [{NiCl2(PN)}4] (PN=2-diphenylphosphinomethyl-2-oxazoline or -2-thiazoline; see picture; Ni green, Cl pink, P orange, S yellow, N blue, C gray) have an unprecedented, centrosymmetric Ni4Cl8 core with 20-electron metal centers and undergo pressure-induced fragmentation into the mononuclear, square-planar 16-electron complexes [NiCl2(PN)], which are in equilibrium with the respective tetramer in solution.

    2. A “Teflon-Footed” Resorcinarene: A Hexameric Capsule in Fluorous Solvents and Fluorophobic Effects on Molecular Encapsulation (pages 6442–6445)

      Shoichi Shimizu, Toshiyuki Kiuchi and Na Pan

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200702344

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      A slippery character: Cyclooligomerization of resorcinol with a highly fluorinated aldehyde afforded a “teflon-footed” resorcinarene 1F, which is soluble in wet fluorous solvents through formation of a hexameric capsule. The supramolecular capsules in fluorous solvents exhibited more selective and/or enhanced properties as a result of fluorophobic effects on molecular encapsulation (such as encapsulating eight molecules of benzene, see picture).

    3. Controlled Hybrid Nanostructures through Protein-Mediated Noncovalent Functionalization of Carbon Nanotubes (pages 6446–6449)

      Katri Kurppa, Hua Jiang, Géza R. Szilvay, Albert G. Nasibulin, Esko I. Kauppinen and Markus B. Linder

      Version of Record online: 25 JUL 2007 | DOI: 10.1002/anie.200702298

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      Spread them out: A hierarchically ordered material in which gold nanoparticles are positioned along carbon nanotubes with a spacing of 2.6 nm is described. The organization is achieved by self-assembly and relies on the functionality of a surfactant protein called HFBI (a hydrophobin).

    4. Contribution of a Solute's Chiral Solvent Imprint to Optical Rotation (pages 6450–6452)

      Parag Mukhopadhyay, Gérard Zuber, Peter Wipf and David N. Beratan

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200702273

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      Solvent or solute dissymmetry? The dissymmetric ordering of solvent molecules around the chiral solute (see picture) contributes to the chiroptical signature. Indeed, the solvent can dominate the chiroptical response, as shown for (S)-methyloxirane in benzene.

    5. Experimental Determination of van der Waals Energies in a Biological System (pages 6453–6456)

      Martin A. Wear, Daphne Kan, Amir Rabu and Malcolm D. Walkinshaw

      Version of Record online: 25 JUL 2007 | DOI: 10.1002/anie.200702084

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      Gaze into the crystal: A crystallographic approach for determining and analyzing free energy not only provides a way of measuring binding energy, it also provides a detailed picture identifying, at the atomic level, which interactions are responsible for changes in binding affinity (picture: superposition of dipeptide–cyclophilin 3 structures; We–h are conserved water molecules e–h).

    6. A Fluorescent Sensor Array for Saccharides Based on Boronic Acid Appended Bipyridinium Salts (pages 6457–6459)

      Alexander Schiller, Ritchie A. Wessling and Bakthan Singaram

      Version of Record online: 25 JUL 2007 | DOI: 10.1002/anie.200701888

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      That's discrimination! An array of boronic acid appended bipyridinium salts (BBVs) as receptor units is able to distinguish twelve saccharides in aqueous solution and at neutral pH values by a fluorescent-indicator displacement assay. The picture shows the fluorescence increase of a fluorescent dye with BBV receptors after adding saccharides (D-ribose (Rib), D-glucose (Glc), D-fructose (Fru), melibiose (Mel), and lactulose (Lal)).

    7. Controlling Network–Brush Interactions to Achieve Switchable Adhesion (pages 6460–6463)

      Rita La Spina, Michael R Tomlinson, Lorena Ruiz-Pérez, Arnaud Chiche, Sean Langridge and Mark Geoghegan

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200701796

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      Make up and break up: A pH-responsive system that displays switchable adhesion in situ is described. Polyacid gels and polybases grafted to a substrate (brushes) strongly adhere in water, but in an acidic environment, the gel and brush dissociate. Adhesion can be controlled by environmental acidity and the process can be repeated several times. Such adhesion may be used in actuators, microfluidics, drug delivery, or personal-care products.

    8. Bismuth Complexes Inhibit the SARS Coronavirus (pages 6464–6468)

      Nan Yang, Julian A. Tanner, Bo-Jian Zheng, Rory M. Watt, Ming-Liang He, Lin-Yu Lu, Jie-Qing Jiang, Ka-To Shum, Yong-Ping Lin, Kin-Ling Wong, Marie C. M. Lin, Hsiang-Fu Kung, Hongzhe Sun and Jian-Dong Huang

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200701021

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      Hold tight: Bismuth complexes including ranitidine bismuth citrate effectively inhibit the nucleoside triphosphate hydrolase and DNA unwinding activities of the SARS coronavirus (SCV) helicase and dramatically reduce SCV replication levels in infected cells. This suggests that bismuth-based drugs should be further evaluated for the treatment of SCV infections in vivo. ss=single-stranded DNA, ds=duplex DNA.

    9. Shiga Toxin-Mediated Retrograde Delivery of a Topoisomerase I Inhibitor Prodrug (pages 6469–6472)

      Abdessamad El Alaoui, Frédéric Schmidt, Mohamed Amessou, Marianne Sarr, Didier Decaudin, Jean-Claude Florent and Ludger Johannes

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200701270

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      A retrograde strategy: An innovative cancer-cell delivery concept exploits the naturally evolved characteristics of the Shiga toxin B-subunit (STxB) for the intracellular activation of a newly synthesized prodrug at the level of the biosynthetic/secretory pathway (see picture). Retrograde prodrug targeting allows its slow release, which should sustain the presence of the active principle in dividing tumor cells.

    10. Fluorescent Carbon Nanoparticles Derived from Candle Soot (pages 6473–6475)

      Haipeng Liu, Tao Ye and Chengde Mao

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200701271

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      Flame and fluorescence: Water-soluble, multicolor fluorescent carbon nanoparticles are prepared by refluxing candle soot with nitric acid (see picture). The starting materials are easily accessible and inexpensive.

    11. Amplified Chiral Transformation through Helical Assembly (pages 6476–6480)

      Kunihiko Toyofuku, Md. Akhtarul Alam, Akihiko Tsuda, Norifumi Fujita, Shigeru Sakamoto, Kentaro Yamaguchi and Takuzo Aida

      Version of Record online: 16 JUL 2007 | DOI: 10.1002/anie.200701668

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      Majority rules: “Chiral amplification” in asymmetric transformations can be realized if a helical supramolecular polymer, derived from the substrate (S), obeys the “majority rule” in determining its handedness. This concept works properly for the asymmetric transformation of a chirality-memorizing D2-symmetric saddle-shaped porphyrin.

    12. Assignment of the Absolute Configuration of the Marine Pentacyclic Polyether (+)-Enshuol by Total Synthesis (pages 6481–6484)

      Yoshiki Morimoto, Hiromi Yata and Yoshihiro Nishikawa

      Version of Record online: 31 JUL 2007 | DOI: 10.1002/anie.200701737

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      Finding its true identity: The complete stereostructure of the marine pentacyclic triterpene polyether (+)-enshuol is shown. Asymmetric total synthesis confirmed the configuration predicted on the basis of NMR spectroscopic data of the previously synthesized natural products aurilol and glabrescol, substructures of which are present in enshuol, and disproved an earlier prediction based on biogenetic considerations.

    13. Parallel Syntheses of (+)- and (−)-α-Cuparenone by Radical Combination in Crystalline Solids (pages 6485–6487)

      Arunkumar Natarajan, Danny Ng, Zhe Yang and Miguel A. Garcia-Garibay

      Version of Record online: 26 JUL 2007 | DOI: 10.1002/anie.200700679

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      Photo[Organic]synthesis: Irradiation of well-designed crystalline ketones can result in the solvent-free generation of compounds having adjacent quaternary stereogenic centers, as illustrated for the enantiospecific synthesis of the natural products (+)- and (−)-(α)-cuparenone (see picture).

    14. Ruthenium-Catalyzed Enantioselective Propargylation of Aromatic Compounds with Propargylic Alcohols via Allenylidene Intermediates (pages 6488–6491)

      Hiroshi Matsuzawa, Yoshihiro Miyake and Yoshiaki Nishibayashi

      Version of Record online: 5 JUN 2007 | DOI: 10.1002/anie.200701261

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      High enantioselectivity was achieved in the Ru-catalyzed propargylation of furans and N,N-dimethylaniline derivatives to afford the propargylated aromatic compounds. This first asymmetric propargylation of aromatic compounds provides a novel protocol for the asymmetric Friedel–Crafts alkylation using propargylic alcohols as a new type of electrophile. Cp*=C5Me5

    15. Stereoselective Synthesis of Isoxazolidines through Pd-Catalyzed Carboetherification of N-Butenylhydroxylamines (pages 6492–6494)

      Michael B. Hay and John P. Wolfe

      Version of Record online: 26 JUL 2007 | DOI: 10.1002/anie.200701386

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      Pd ploy to isoxazolidines: Carboetherification reactions of N-butenylhydroxylamines with aryl bromides afford substituted isoxazolidines in good yield with up to >20:1 d.r. These transformations provide a new strategy for the construction of isoxazolidines and allow for the synthesis of isoxazolidine stereoisomers that cannot be prepared with existing methods.

    16. Metal-Free Synthesis of Sterically Crowded Biphenyls by Direct Ar[BOND]H Substitution in Alkyl Benzenes (pages 6495–6498)

      Valentina Dichiarante, Maurizio Fagnoni and Angelo Albini

      Version of Record online: 24 JUL 2007 | DOI: 10.1002/anie.200701462

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      Four's definitely a crowd: The chemoselective activation of Ar[BOND]H bonds in methylbenzenes by treatment with photogenerated phenyl cations allowed the synthesis of sterically crowded biphenyl compounds, including tetra-ortho-substituted biphenyls, by intermolecular cross-coupling (see scheme). This method is an appealing metal-free alternative to widely used transition-metal catalysis. TFE=2,2,2-trifluoroethanol.

    17. Supramolecular Solid–Gas Complexes: A Thermodynamic Approach (pages 6499–6501)

      Alexander G. Grechin, Hans-Jürgen Buschmann and Eckhard Schollmeyer

      Version of Record online: 24 JUL 2007 | DOI: 10.1002/anie.200701666

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      Phasing up to complex problems: A thermodynamic approach based on solution data has been proposed for the determination of the stability of gas complexes and elucidation of the selectivity of gas binding. Stability constants, reaction enthalpies, and entropies for the complexation of gaseous guests (n-alkylamines) by solid macrocyclic hosts (β-cyclodextrin, cucurbit[6]uril) were calculated by using the Born–Haber type cycle (see picture).

    18. Total Synthesis of Pederin (pages 6502–6504)

      John C. Jewett and Viresh H. Rawal

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200701677

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      Blisteringly fast: The potent cytotoxic blistering agent pederin has been synthesized (see scheme). The synthesis is diastereoselective and concise (just 12 steps for the longest linear sequence), and features a formal hetero-Diels–Alder reaction of a hindered diene, a Mukaiyama–Michael reaction to set two additional stereocenters, and a Curtius rearrangement to stereospecifically introduce the aminal functionality.

    19. FeCl2-Catalyzed Selective C[BOND]C Bond Formation by Oxidative Activation of a Benzylic C[BOND]H Bond (pages 6505–6507)

      Zhiping Li, Lin Cao and Chao-Jun Li

      Version of Record online: 25 JUL 2007 | DOI: 10.1002/anie.200701782

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      Any old iron: Readily available and nontoxic FeCl2 effectively catalyzes C[BOND]C bond formation by oxidative activation of benzylic C[BOND]H bonds in the presence of tert-butyl peroxide as a stoichiometric oxidant (see scheme). The mild reaction conditions, good yields, low catalyst cost, and easy operation are the major advantages of this cross-dehydrogenation coupling reaction.

    20. Rare-Earth Metal Mixed Chloro/Methyl Compounds: Heterogeneous–Homogeneous Borderline Catalysts in 1,3-Diene Polymerization (pages 6508–6513)

      Christian Meermann, Karl W. Törnroos, Willy Nerdal and Reiner Anwander

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200604829

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      On the right path: A chlorination–alkylation sequence involving the reaction of preformed mixed amido/chloro complexes (see structure) with trimethylaluminum causes precipitation of [{LnaAlbMecCld}n], which for Ln=Nd polymerizes isoprene in greater than 99 % cis stereospecificity (Mn/Mw=1.76); the catalyst performance is comparable to that observed following a “detour” alkylation–chlorination sequence employing [Nd(AlMe4)3]/Et2AlCl.

    21. Short, Facile, and High-Yielding Synthesis of Extremely Efficient Pincer-Type Suzuki Catalysts Bearing Aminophosphine Substituents (pages 6514–6517)

      Jeanne L. Bolliger, Olivier Blacque and Christian M. Frech

      Version of Record online: 24 JUL 2007 | DOI: 10.1002/anie.200701804

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      Feeling the pinch: Aryl bromides can be coupled with phenylboronic acid quantitatively within a few minutes by using pincer-type catalysts bearing aminophosphine substituents. [Pd(Cl)2P(NR2)3] has been used as a template for the pincer core directly on the metal center (see scheme, NR2=piperidinyl, X=NH or O), which makes the independent synthesis and purification of the air- and moisture-sensitive ligand systems unnecessary.

    22. Manganese-Catalyzed Insertion of Aldehydes into a C[BOND]H Bond (pages 6518–6520)

      Yoichiro Kuninobu, Yuta Nishina, Takahiro Takeuchi and Kazuhiko Takai

      Version of Record online: 24 JUL 2007 | DOI: 10.1002/anie.200702256

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      Mn gets in the game: In the presence of a manganese catalyst and a stoichiometric amount of hydrosilane, aldehydes insert into C[BOND]H bonds of aromatic rings of compounds with directing groups (see scheme). This first example of a manganese-catalyzed chemical transformation through C[BOND]H bond activation gives silyl ethers in good to excellent yields and can also be applied to asymmetric transformation.

    23. Iron-Catalyzed Cross-Coupling of Alkyl Halides with Alkenyl Grignard Reagents (pages 6521–6524)

      Amandine Guérinot, Sébastien Reymond and Janine Cossy

      Version of Record online: 26 JUL 2007 | DOI: 10.1002/anie.200702206

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      Cheap and safe: An iron-catalyzed cross-coupling reaction between alkyl halides and alkenyl Grignard reagents is described. This C[BOND]C bond coupling reaction is promoted by the cheap and nontoxic FeCl3 and displays good tolerance against various functional groups.

    24. Homoleptic Crown N-Heterocyclic Carbene Complexes (pages 6525–6528)

      Ross McKie, John A. Murphy, Stuart R. Park, Mark D. Spicer and Sheng-ze Zhou

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200702138

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      Two ways about it: The first metal N-heterocyclic carbene complexes derived from a cyclic tetraimidazolium salt show a remarkable versatility of ligand conformation and coordination geometry. With PdII, a mononuclear square-planar complex is obtained, but with CuI and AgI, an unprecedented dinuclear motif with a short metal–metal interaction is observed (see structure; N blue, C white ellipsoids, H white circles).

    25. Tetrafluoro-IBA and-IBX: Hypervalent Iodine Reagents (pages 6529–6532)

      Robert D. Richardson, Jameel M. Zayed, Sabine Altermann, Daniel Smith and Thomas Wirth

      Version of Record online: 23 JUL 2007 | DOI: 10.1002/anie.200702313

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      Fluorine makes the difference: FIBX (see structure), the tetrafluoro derivative of the hypervalent iodine reagent, is more soluble and has higher reactivity than its nonfluorinated counterpart. An efficient synthesis of FIBX and initial reactions are presented. Some of these reactions can be conducted in standard organic solvents. Owing to the increased reactivity, new transformations and catalytic reactions may be possible.

    26. Homolytic Substitution at Phosphorus for the Synthesis of Alkyl and Aryl Phosphanes (pages 6533–6536)

      Santiago E. Vaillard, Christian Mück-Lichtenfeld, Stefan Grimme and Armido Studer

      Version of Record online: 18 JUL 2007 | DOI: 10.1002/anie.200701650

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      A transition-metal-free radical phosphonation using Me3SnPPh2 and the less toxic Me3SiPPh2 is reported. These readily available reagents react highly efficiently with primary and secondary alkyl radicals. Moreover, aryl radicals and tertiary alkyl radicals are phosphonated with Me3SnPPh2 (see scheme; R=aryl, alkyl, vinyl; X=I, Br, OC(S)imidazolyl). DFT calculations provide insights into the mechanism of the reaction.

    27. Discrimination of β-Ketoesters by Ruthenium(II)–Binap-Catalyzed Asymmetric Hydrogenation (pages 6537–6541)

      Rainer Kramer and Reinhard Brückner

      Version of Record online: 25 JUL 2007 | DOI: 10.1002/anie.200700021

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      Please, after you… β-Ketoesters in mixtures underwent Noyori reduction one by one at room temperature under 4 bar of hydrogen pressure in the presence of a catalyst formed from RuII and (S)-binap (see example). The rate of the asymmetric hydrogenation and hence the selectivity for a particular β-ketoester was found to depend on the Lewis basicity of the ester group. Binap=2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl.

    28. Divergent Reactions for Racemates: Catalytic, Enantioselective, and Regiodivergent Nitroso Diels–Alder Reactions (pages 6542–6544)

      Chandan Kumar Jana and Armido Studer

      Version of Record online: 25 JUL 2007 | DOI: 10.1002/anie.200701631

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      Two products out of eight possible isomers are obtained from the [CuPF6(MeCN)4]-catalyzed, highly enantioselective, and regiodivergent nitroso Diels–Alder reactions of 6-substituted 1,3-cyclohexadienes (see scheme; R=phenyl, alkyl; Ar=2-pyridyl). These divergent reactions of racemic cyclohexadienes deliver valuable compounds for the synthesis of biologically interesting carbasugars. In a first application peracetylated 2-epi-validamine was synthesized.

    29. 1,1′-Linked Cyclopropane Derivatives: The Helical Conformation of Quinquecyclopropanol (pages 6545–6548)

      Takuya Kurahashi, Sergei I. Kozhushkov, Heiko Schill, Kathrin Meindl, Stephan Rühl and Armin de Meijere

      Version of Record online: 24 JUL 2007 | DOI: 10.1002/anie.200702013

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      In a twist: 1,1′-Linked oligocyclopropanols have been obtained by an iterated reaction of a cyclopropaneboronate with in situ generated lithium bromocyclopropylidenoid and subsequent oxidation. As predicted by DFT computations for sexicyclopropane (shown in blue) in the gas phase, the quinquecyclopropane unit in the 3,5-dinitrobenzoate of quinquecyclopropanol (yellow, dinitrobenzoyl group omitted for clarity) adopts a helical conformation in the crystal.

    30. Ga24Br18Se2: A Highly Symmetrical Metalloid Cluster and Its One-Dimensional Arrangement in the Crystalline State as a Model for the Photoconductivity of Solid GaSe (pages 6549–6552)

      Jens Hartig, Frederik Klöwer, Julia Rinck, Andreas-Neil Unterreiner and Hansgeorg Schnöckel

      Version of Record online: 25 JUL 2007 | DOI: 10.1002/anie.200701986

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      Cluster on cluster: [Ga12Ga12(Br18Se2)]⋅12 THF units with a platonic polyhedral substructure are ordered through the crystal in straight lines by Se[BOND]Se contacts in an arrangement resembling superatoms (see picture). According to topological, spectroscopic, and energetic findings, these chains of clusters can be interpreted as a model for the lattice structure of photoconducting GaSe.

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