Angewandte Chemie International Edition

Cover image for Vol. 47 Issue 37

September 1, 2008

Volume 47, Issue 37

Pages 6925–7139

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlights
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Cover Picture: Gold(I)-Template Catenane and Rotaxane Synthesis (Angew. Chem. Int. Ed. 37/2008) (page 6925)

      Stephen M. Goldup, David A. Leigh, Paul J. Lusby, Roy T. McBurney and Alexandra M. Z. Slawin

      Article first published online: 27 AUG 2008 | DOI: 10.1002/anie.200890180

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      There's gold in them thar rings according to David Leigh and co-workers in their Communication on page 6999 ff. The last of the simple metal coordination geometries—linear—has joined the family of metal–ligand arrangements that have been used to template the formation of the mechanical bond. Catenanes and rotaxanes can be easily synthesized using this versatile gold(I)-directed assembly, suggesting that there may be plenty more treasure uncovered using this interlocking template system.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlights
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Inside Cover: Tailor-Made Inorganic Nanopeapods: Structural Design of Linear Noble Metal Nanoparticle Chains (Angew. Chem. Int. Ed. 37/2008) (page 6926)

      Lifeng Liu, Woo Lee, Roland Scholz, Eckhard Pippel and Ulrich Gösele

      Article first published online: 27 AUG 2008 | DOI: 10.1002/anie.200890181

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      Pt@CoAl2O4 inorganic nanopeapods consisting of well-defined platinum nanoparticle chains embedded in CoAl2O4 nanoshells are synthesized “à la carte” by an approach combining template-based electrodeposition with a high-temperature solid-state reaction route, as described by L. Liu et al. in their Communication on page 7004 ff. The size, separation, and arrangement of platinum nanoparticles can be tuned easily. The nanopeapods are promising building blocks for nanoscale photonic devices.

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. News
    6. Book Reviews
    7. Highlights
    8. Minireview
    9. Review
    10. Communications
    11. Preview
    1. Graphical Abstract: Angew. Chem. Int. Ed. 37/2008 (pages 6929–6940)

      Article first published online: 27 AUG 2008 | DOI: 10.1002/anie.200890182

  4. News

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

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

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

      On-Surface Covalent Coupling in Ultrahigh Vacuum (pages 6950–6953)

      André Gourdon

      Article first published online: 6 AUG 2008 | DOI: 10.1002/anie.200802229

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      Beyond supramolecular self-assembly: On-surface covalent coupling of organic precursors is a powerful method to obtain 1D or 2D robust molecular arrays on a substrate (see picture) that have numerous potential applications in nanotechnology. Significant advances have recently been made in this field including imine formation, dehydration of boronic acids, esterification, as well as radical and carbene coupling reactions.

    2. C[BOND]C Coupling

      Catalysts for the Sonogashira Coupling—The Crownless Again Shall Be King (pages 6954–6956)

      Herbert Plenio

      Article first published online: 5 AUG 2008 | DOI: 10.1002/anie.200802270

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      Commoners displacing the nobility? The scope of the Sonogashira coupling is widening with the discovery of new catalytic systems based on a variety of metals (see picture). In particular, cheap common metals are finding a place in transformations that were previously controlled by noble metals. The developments are examined, and the advantages and disadvantages of the various catalytic systems are discussed.

    3. Tunnel Effect

      Hydroxycarbene: Watching a Molecular Mole at Work (pages 6957–6958)

      Götz Bucher

      Article first published online: 8 AUG 2008 | DOI: 10.1002/anie.200803195

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      Finding a pico-mole: like a mole, hydroxycarbene prefers to tunnel through barriers. Generated from glyoxylic acid by pyrolysis, H[BOND]C[BOND]OH rearranges to formaldehyde within two hours even in solid argon at T=10 K. This behavior is best rationalized by quantum mechanical tunneling.

  7. Minireview

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

      “Nonsolvent” Applications of Ionic Liquids in Biotransformations and Organocatalysis (pages 6960–6968)

      Pablo Domínguez de María

      Article first published online: 24 JUL 2008 | DOI: 10.1002/anie.200703305

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      More than mere solvents: Room-temperature ionic liquids (RTILs) are generally regarded as promising neoteric solvents for bio- and organocatalytic reactions. This Minireview highlights other applications of RTILs and shows that the potential of these compounds extends well beyond their use as versatile solvents (see example in scheme). Many of the concepts examined can be implemented readily in other areas of chemistry. DMSO=dimethyl sulfoxide.

  8. Review

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

      Chirality Recognition between Neutral Molecules in the Gas Phase (pages 6970–6992)

      Anne Zehnacker and Martin A. Suhm

      Article first published online: 11 AUG 2008 | DOI: 10.1002/anie.200800957

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      Relative handedness matters: Chirality recognition phenomena may be classified according to the lifetime of the chiral configurations of the interacting partners, leading to differentiation between chirality discrimination, chirality induction, and chirality synchronization processes. These phenomena are studied in vacuum isolation at low temperature, using rotational, vibrational, electronic, and photoionization spectroscopy.

  9. Communications

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

      Bicomponent Supramolecular Packing in Flexible Phthalocyanine Networks (pages 6994–6998)

      Bastien Calmettes, Samuthira Nagarajan, André Gourdon, Mathieu Abel, Louis Porte and Roland Coratger

      Article first published online: 28 JUL 2008 | DOI: 10.1002/anie.200802628

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      Reading between the lines: Three types of weakly bonded networks are observed when octachlorozinc phthalocyanine molecules are adsorbed onto Ag(111). Insertion of a corannulene guest into these phases to give either stable lines or chessboard structures can be observed by scanning tunneling microscopy (see picture). Corannulene molecules can be removed from the bicomponent packing at 4.6 K, which leads to artificial patterning of the surface.

    2. Gold(I)-Template Synthesis

      Gold(I)-Template Catenane and Rotaxane Synthesis (pages 6999–7003)

      Stephen M. Goldup, David A. Leigh, Paul J. Lusby, Roy T. McBurney and Alexandra M. Z. Slawin

      Article first published online: 15 JUL 2008 | DOI: 10.1002/anie.200801904

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      Gold member: The last of the simple metal coordination geometries (linear) joins the family of metal–ligand arrangements that have been used to template the formation of mechanical bonds. Both catenanes and rotaxanes are assembled about a gold(I) template. The picture shows the molecular structure of the gold(I) catenate, viewed parallel to its N[BOND]Au[BOND]N bond.

    3. Nanoparticle Chains

      Tailor-Made Inorganic Nanopeapods: Structural Design of Linear Noble Metal Nanoparticle Chains (pages 7004–7008)

      Lifeng Liu, Woo Lee, Roland Scholz, Eckhard Pippel and Ulrich Gösele

      Article first published online: 28 JUL 2008 | DOI: 10.1002/anie.200801931

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      Pt@CoAl2O4inorganic nanopeapods (see picture) consisting of well-defined Pt nanoparticle chains embedded in CoAl2O4 are synthesized by the pulsed electrodeposition of Co/Pt multilayered nanowires into an anodic aluminum oxide (AAO) membrane and a subsequent high-temperature solid-state reaction between Co/Pt nanowires and AAO. The pulse durations for Pt and Co depositions control the size and separation of Pt nanoparticles.

    4. Fluoroaromatics

      Aromatic Fluorine as a Versatile Control Element for the Construction of Molecules with Helical Chirality (pages 7009–7012)

      Tim Rasmusson, L. James P. Martyn, Gang Chen, Alan Lough, Megan Oh and Andrei K. Yudin

      Article first published online: 31 JUL 2008 | DOI: 10.1002/anie.200801991

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      Partially fluorinated binol scaffolds (see picture) offer a versatile entry into helically chiral materials. The different fluorine substitution patterns in these molecules lead to substantial changes in their crystal packing arrangements, which should facilitate the discovery and development of novel materials for applications ranging from semiconductor synthesis to catalysis.

    5. Cycloaddition

      Enantioselective Oxazaborolidinium-Catalyzed Diels–Alder Reactions without CH⋅⋅⋅⋅O Hydrogen Bonding (pages 7013–7017)

      Michael N. Paddon-Row, Laurence C. H. Kwan, Anthony C. Willis and Michael S. Sherburn

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200802002

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      Allcis-tems go! The first detailed computational investigations into the title reaction validate Corey's two pre-transition-state models and reveal a third Lewis acid coordination mode (see picture), which operates for esters having s-cis C[DOUBLE BOND]C[BOND]C[DOUBLE BOND]O groups. The new pre-transition-state model explains the unexpected enantioselectivity witnessed for several Diels–Alder reactions and does not involve a C[BOND]H⋅⋅⋅O hydrogen bond.

    6. Enzyme Engineering

      An Engineered Aryl Azide Ligase for Site-Specific Mapping of Protein–Protein Interactions through Photo-Cross-Linking (pages 7018–7021)

      Hemanta Baruah, Sujiet Puthenveetil, Yoon-Aa Choi, Samit Shah and Alice Y. Ting

      Article first published online: 4 AUG 2008 | DOI: 10.1002/anie.200802088

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      Labeled and linked: The small-molecule binding site of Escherichia coli lipoic acid ligase was re-engineered to accept a fluorinated aryl azide probe in place of lipoic acid. Labeling with this mutant is highly specific for LAP fusion proteins. In cell lysate, FK506 binding protein was labeled and rapamycin-dependent photo-cross-linking to its interaction partner was demonstrated.

    7. Supramolecular complexes

      Anion-Directed Self-Assembly of Flexible Ligands into Anion-Specific and Highly Symmetrical Organic Solids (pages 7022–7025)

      Krunoslav Užarević, Ivica Đilović, Dubravka Matković-Čalogović, Dubravka Šišak and Marina Cindrić

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200802193

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      One ring to rule them out: Preorganization of simple polyamine podands in the presence of nitrate or sulfate affords a new kind of C3-symmetrical supramolecular ring. Although not rigid, the ring's cavity is stabilized by a network of noncovalent interactions and displays an amazing level of selectivity for these two anions in a number of competitive anion/solvent environments.

    8. Molecular Devices

      A Contractile DNA Machine (pages 7026–7028)

      Daniel Lubrich, Jie Lin and Jie Yan

      Article first published online: 4 AUG 2008 | DOI: 10.1002/anie.200800476

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      Machine tool: A molecular machine built from DNA utilizes the cooperative actions of many molecular tweezers units to achieve larger-scale movements. The device is able to contract to 75 % of its fully extended length (see picture), is driven by a set of two “fuel” strands, and can be cycled.

    9. Protein Modifications

      Functionalized Nanocompartments (Synthosomes) with a Reduction-Triggered Release System (pages 7029–7031)

      Ozana Onaca, Pransenjit Sarkar, Danilo Roccatano, Thomas Friedrich, Bernard Hauer, Mariusz Grzelakowski, Arcan Güven, Marco Fioroni and Ulrich Schwaneberg

      Article first published online: 4 AUG 2008 | DOI: 10.1002/anie.200801076

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      An open and shut case: The developed synthosomes are a subclass of polymersomes with a block-copolymer membrane and a modified embedded transmembrane channel protein (FhuA Δ1–160; see top view of model), which acts as a selective gate. The first reduction-triggered and sterically controlled release system for transmembrane control of the chemical fluxes has been developed by chemically labeling lysine residues in the channel of FhuA Δ1–160.

    10. Magnetic Materials

      A Perovskite Containing Quadrivalent Iron as a Charge-Disproportionated Ferrimagnet (pages 7032–7035)

      Ikuya Yamada, Kazuhide Takata, Naoaki Hayashi, Satoshi Shinohara, Masaki Azuma, Shigeo Mori, Shigetoshi Muranaka, Yuichi Shimakawa and Mikio Takano

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200801482

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      Ferri interesting: CaCuII3FeIV4O12, prepared at 15 GPa and 1300 K, undergoes a charge disproportionation (2 FeIV[RIGHTWARDS ARROW]FeIII+FeV) and electrical, magnetic, and structural changes at 210 K. The FeIIIO6 and FeVO6 octahedra are ordered in a rock-salt manner (see picture; Ca gray, O blue, Cu red), and the low-temperature phase has the ferrimagnetic structure CuII(S=1/2,[DOWNWARDS ARROW])3FeIII(S=5/2,[UPWARDS ARROW])2FeV(S=3/2,[UPWARDS ARROW])2.

    11. Programmed Nanopores

      Directed Assembly of Sub-Nanometer Thin Organic Materials with Programmed-Size Nanopores (pages 7036–7039)

      Delia C. Danila, L. Todd Banner, Evguenia J. Karimova, Lyudmila Tsurkan, Xinyan Wang and Eugene Pinkhassik

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200801814

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      Nanocolander: Sub-nanometer thin organic materials with uniform imprinted pores are formed by controlled polymerization within temporary self-assembled scaffolds. Pores are measured by a colored size-probe retention assay. A nanocapsule with no pores retains yellow, red, and blue probes and is colored brown; 0.8 nm pores lead to release of yellow probes, while capsules with 1.3 nm pores only retain blue probes.

    12. Gold Catalysis

      Gold-Catalyzed Waste-Free Generation and Reaction of Azomethine Ylides: Internal Redox/Dipolar Cycloaddition Cascade (pages 7040–7043)

      Hyun-Suk Yeom, Ji-Eun Lee and Seunghoon Shin

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200802802

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      High-octane synthesis: Azomethine ylides can be generated from an internal redox reaction of a nitrone-tethered alkyne under electrophilic metal catalysis (see scheme; M=metal). This novel and atom-economical generation of an azomethine ylide does not involve potentially explosive diazo derivatives. The azomethine ylide can participate in a dipolar cycloaddition cascade to provide an azabicyclo[3.2.1]octane.

    13. Multicomponent Reactions

      Synthesis of Spiroquinolines through a One-Pot Multicatalytic and Multicomponent Cascade Reaction (pages 7044–7047)

      José Barluenga, Abraham Mendoza, Félix Rodríguez and Francisco J. Fañanás

      Article first published online: 31 JUL 2008 | DOI: 10.1002/anie.200802582

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      Three's company: Functionalized spirocyclic quinoline derivatives are easily synthesized in a one-pot three-component coupling process involving the reaction of alkynol, aldehyde, and aniline derivatives (see scheme). The process is carried out in the presence of catalytic amounts of a platinum(II) complex and a protic acid.

    14. Asymmetric Catalysis

      Enantioselective Nucleophilic Catalysis: The Synthesis of Aza-β-Lactams through [2+2] Cycloadditions of Ketenes with Azo Compounds (pages 7048–7050)

      Jacob M. Berlin and Gregory C. Fu

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200802439

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      Get ready for take off: A planar-chiral derivative of 4-pyrrolidinopyridine (1) mediates the title transformation (see scheme) in a convergent manner with good enantioselectivity, thus giving the first catalytic asymmetric synthesis of aza-β-lactams.

    15. Tungsten Photocatalysts

      Nanoporous-Walled Tungsten Oxide Nanotubes as Highly Active Visible-Light-Driven Photocatalysts (pages 7051–7055)

      Zhi-Gang Zhao and Masahiro Miyauchi

      Article first published online: 28 JUL 2008 | DOI: 10.1002/anie.200802207

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      Shine a light! High-purity tungstic acid hydrate nanotubes and nanoporous-walled WO3 nanotubes (see picture) were synthesized. The platinum-loaded WO3 nanotubes show a photocatalytic activity in the degradation of acetaldehyde about three and eight times greater than that of commercial WO3 particles and nitrogen-doped TiO2, respectively.

    16. Peptide Chemistry

      How Useful Is Ferrocene as a Scaffold for the Design of β-Sheet Foldamers? (pages 7056–7059)

      Somenath Chowdhury, Gabriele Schatte and Heinz-Bernhard Kraatz

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200801460

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      Crease crossing peptide embossing: The first tripeptide ferrocene foldamers to adopt an extended β-sheet-like structure in solution and solid state are presented. The flexibility of peptide substituents in 1,n′-ferrocene-bispeptide conjugates was thought to prevent the formation of extended β-sheet foldamers. The results suggest that ferrocene is a valuable scaffold for extended β-sheets.

    17. Asymmetric Cyclodextrins

      Regiospecific Tandem Azide-Reduction/Deprotection To Afford Versatile Amino Alcohol-Functionalized α- and β-Cyclodextrins (pages 7060–7063)

      Samuel Guieu and Matthieu Sollogoub

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200801573

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      Cyclic conundrum: Deciphering the cyclic directionality of cyclodextrins allows the precise regiospecific synthesis of functionalized cyclodextrins with diametrically opposed amino and hydroxy groups (see scheme; DIBAL-H=diisobutylaluminum hydride, Bn=benzyl) through a tandem azide-reduction/debenzylation mechanism. A remarkable feature of this process is the long-distance discrimination between two equidistant benzyl groups on β-cyclodextrin.

    18. Dioxygen Activation

      Proton- and Reductant-Assisted Dioxygen Activation by a Nonheme Iron(II) Complex to Form an Oxoiron(IV) Intermediate (pages 7064–7067)

      Aurore Thibon, Jason England, Marlène Martinho, Victor G. Young Jr., Jonathan R. Frisch, Régis Guillot, Jean-Jacques Girerd, Eckard Münck, Lawrence Que Jr. and Frédéric Banse

      Article first published online: 4 AUG 2008 | DOI: 10.1002/anie.200801832

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      With a little help from some friends: With the aid of HClO4 as proton and BPh4 as electron source, the Fe complex of a pentadentate pyridyl-appended cyclam ligand can activate dioxygen to yield the corresponding oxoiron(IV) complex (see scheme; TMC-py=1-(2′-pyridylmethyl)-4,8,11-trimethyl-1,4,8,11-tetraazacyclotetradecane; C gray, Fe magenta, N blue, O red). This transformation is proposed to occur via a hydroperoxoiron(III) intermediate.

    19. Cycloadditions

      Synthesis of Cyclopentenones from Cyclopropanes and Silyl Ynol Ethers (pages 7068–7070)

      Xiangbing Qi and Joseph M. Ready

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200801957

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      Exploiting an opening: Lewis acid promoted ring-opening of donor–acceptor cyclopropanes generates a 1,3-zwitterion; cycloaddition with a silyl ynol ether leads to a general synthesis of cyclopentenones (see scheme). Substitution is tolerated on the ynol and on all positions of the cyclopropane to give tri-, tetra-, and penta-substituted cyclopentenones in high yield.

    20. Reactive Intermediates

      Spectroscopic Identification of Dihydroxycarbene (pages 7071–7074)

      Peter R. Schreiner and Hans Peter Reisenauer

      Article first published online: 29 JUL 2008 | DOI: 10.1002/anie.200802105

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      Out and about: CO2 extrusion from simple α-keto carboxylic acids can be used to prepare hitherto unknown hydroxycarbenes. High-vacuum flash pyrolysis of oxalic acid or its monomethyl ester enabled the preparation and characterization of dihydroxy- (1) and hydroxymethoxycarbene, respectively, both of which are stabilized through π-type out-of-plane and in-plane σ conjugation (the HOMO of s-trans,s-trans-1 is shown).

    21. Synthetic Methods

      Functionalizing Glycine Derivatives by Direct C[BOND]C Bond Formation (pages 7075–7078)

      Liang Zhao and Chao-Jun Li

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200801367

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      Come on glycine: Two different types of glycine derivatives are α-functionalized using cross-dehydrogenative-coupling (CDC) reactions. The method allows the efficient attachment of a malonate or aromatic alkyne group on the α-position of the glycine derivatives under very mild conditions.

    22. Asymmetric Catalysis

      Highly Enantioselective Direct Michael Addition of Nitroalkanes to Nitroolefins Catalyzed by La(OTf)3/N,N′-Dioxide Complexes (pages 7079–7081)

      Xu Yang, Xin Zhou, Lili Lin, Lu Chang, Xiaohua Liu and Xiaoming Feng

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200802285

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      It all adds up: A chiral La(OTf)3/N,N′-dioxide complex has been developed for the asymmetric direct Michael addition of nitroalkanes to nitroalkenes. This reaction afford 1,3-dinitro compounds with two stereocenters in good yields with high diastereo- and enantioselectivity (up to d.r. 93:3, 97 % ee; see scheme, Tf=trifluoromethanesulfonyl) under mild conditions.

    23. Synthetic Methods

      Ortho-TMS Benzaldehyde: An Effective Linchpin for Type II Anion Relay Chemistry (ARC) (pages 7082–7086)

      Amos B. Smith III, Won-Suk Kim and William M. Wuest

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200802301

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      ARC de triomphe: Ortho-TMS benzaldehyde permits efficient multicomponent union of a variety of nucleophiles and electrophiles, including the first example of a Pd-mediated ARC Type II process. A “proof-of-concept” synthetic sequence was designed and implemented for construction of a focused library of “natural product-like” compounds (see scheme). ARC: anion relay chemistry.

    24. Activation of the C[BOND]F Bond: Transformation of CF3N[DOUBLE BOND]N- into 5-Azidotetrazoles (pages 7087–7090)

      Takashi Abe, Guo-Hong Tao, Young-Hyuk Joo, Yangen Huang, Brendan Twamley and Jean'ne M. Shreeve

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200802459

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      N&Ns: The C[BOND]F bond of trifluoromethylazoalkanes, in the presence of a hydrogen at the α carbon, is activated under basic conditions to form a difluoromethylene intermediate with a conjugated double bond, which is transformed in good yield to the corresponding 5-azido-(1-dialkylimino)tetrazole by reaction with NaN3.

    25. Natural Product Synthesis

      Total Synthesis of Pinnatoxin A (pages 7091–7094)

      Seiichi Nakamura, Fumiaki Kikuchi and Shunichi Hashimoto

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200802729

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      A familiar ring: A ruthenium-catalyzed cycloisomerization of an enyne, synthesized by an exo-selective Diels–Alder reaction with an α-methylene lactone as the dienophile, proved to be highly effective for the construction of the 27-membered carbocycle of pinnatoxin A. The total synthesis was completed upon the formation of the seven-membered cyclic imine by self-catalyzed dehydration.

    26. Nonlinear Optics

      Porphyrin Dimer Carbocations with Strong Near Infrared Absorption and Third-Order Optical Nonlinearity (pages 7095–7098)

      Karl J. Thorley, Joel M. Hales, Harry L. Anderson and Joseph W. Perry

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200802687

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      Colored carbocations beyond the visible! A porphyrin dimer carbocation is synthesized with effective delocalization over 18 conjugated bonds. Placing a carbocation at the center of a conjugated porphyrin dimer shifts its absorption into the infrared and results in strong ultrafast nonlinear optical behavior.

    27. Foldamers

      A Nonpeptidic Reverse Turn that Promotes Parallel Sheet Structure Stabilized by C[BOND]H⋅⋅⋅O Hydrogen Bonds in a Cyclopropane γ-Peptide (pages 7099–7102)

      Christopher R. Jones, M. Khurram N. Qureshi, Fiona R. Truscott, Shang-Te Danny Hsu, Angus J. Morrison and Martin D. Smith

      Article first published online: 30 JUL 2008 | DOI: 10.1002/anie.200802648

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      A twist of fate: Parallel-turn linkers comprising an amino acid derived alcohol conjoined with an aromatic amide through a flexible linkage adopt reverse-turn conformations. Cyclopropane tetra- and hexapeptide analogues form a C[BOND]H⋅⋅⋅O hydrogen-bond-stabilized parallel-sheet conformation (see scheme). NMR studies confirm the presence of hydrogen bonds in these structures.

    28. Synthetic Methods

      Palladium/Copper-Catalyzed Decarboxylative Cross-Coupling of Aryl Chlorides with Potassium Carboxylates (pages 7103–7106)

      Lukas J. Gooßen, Bettina Zimmermann and Thomas Knauber

      Article first published online: 6 AUG 2008 | DOI: 10.1002/anie.200800728

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      Even non-activated aryl chlorides undergo decarboxylative cross-coupling reactions in the presence of a catalyst system generated in situ from CuI, 1,10-phenanthroline, PdI2, and di(tert-butyl)biphenylphosphane. The new catalyst is useful for both the synthesis of biaryl compounds from aromatic carboxylates and the synthesis of aryl ketones from salts of α-ketocarboxylic acids (see scheme; FG=functional group; R=aryl, alkyl).

    29. Activation of Alkanes

      Semiconductor-Photocatalyzed Sulfoxidation of Alkanes (pages 7107–7109)

      Francesco Parrino, Ayyappan Ramakrishnan and Horst Kisch

      Article first published online: 5 AUG 2008 | DOI: 10.1002/anie.200800326

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      The C[BOND]H activation of alkanes with visible light is possible with a semiconductor as the photocatalyst. Upon irradiation, a mixture of titanium dioxide, sulfur dioxide, and oxygen can be used to convert alkanes into the corresponding sulfonic acids (see scheme).

    30. Superoxonickel Complexes

      A “Side-on” Superoxonickel Complex [LNi(O2)] with a Square-Planar Tetracoordinate Nickel(II) Center and Its Conversion into [LNi(μ-OH)2NiL] (pages 7110–7113)

      Shenglai Yao, Eckhard Bill, Carsten Milsmann, Karl Wieghardt and Matthias Driess

      Article first published online: 31 JUL 2008 | DOI: 10.1002/anie.200802234

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      Radically mild: The first room-temperature isolable, structurally characterized superoxonickel(II) complex 1 with a square-planar tetracoordinate NiII center is capable of gentle oxygen-transfer reactions to form the proposed intermediate 2, which acts as a hydrogen scavenger and dimerizes to homovalent complex 3 with both square-planar (low-spin) and tetrahedral (high-spin) NiII centers. L=CH{C(Me)(2,6-iPr2C6H3N}2.

    31. Inhibition of Protein Aggregation

      Exploiting Cross-Amyloid Interactions To Inhibit Protein Aggregation but not Function: Nanomolar Affinity Inhibition of Insulin Aggregation by an IAPP Mimic (pages 7114–7118)

      Aleksandra Velkova, Marianna Tatarek-Nossol, Erika Andreetto and Aphrodite Kapurniotu

      Article first published online: 8 AUG 2008 | DOI: 10.1002/anie.200801499

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      Potential aggregate preventer: The designed peptide IAPP-GI inhibits the non-native aggregation of insulin without affecting its function. As the peptide also blocks aggregation of key amyloid peptides that occur in Alzheimer's disease and type II diabetes, it is a promising drug candidate.

    32. RNA Detection

      Target-Catalyzed Transfer Reactions for the Amplified Detection of RNA (pages 7119–7122)

      Tom N. Grossmann, Lars Röglin and Oliver Seitz

      Article first published online: 1 AUG 2008 | DOI: 10.1002/anie.200801355

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      Strong signals: The RNA-catalyzed transfer of a biotin reporter was used to preamplify a signal that was detected in an enzyme-based readout, thereby increasing its sensitivity. The advantages of combining the covalent attachment of biotin and preamplification were demonstrated by the detection of 500 attomol HIV RNA. The flexibility requirements of DNA- and RNA-catalyzed transfer reactions were tested.

    33. Functional Surfaces

      Antimicrobial Surfaces through Natural Product Hybrids (pages 7123–7126)

      Jean-Yves Wach, Simone Bonazzi and Karl Gademann

      Article first published online: 31 JUL 2008 | DOI: 10.1002/anie.200801570

      Thumbnail image of graphical abstract

      The power of two! A natural product hybrid (see structure) composed of a siderophore and an antibiotic separated by a poly(ethylene glycol) linker enables the preparation of antimicrobial and cell-resistant surfaces by a simple dip-and-rinse procedure. The anachelin siderophore (left) binds strongly to TiO2 surfaces, and vancomycin is responsible for antibiotic activity.

    34. Phase Transfer Catalysis

      Pyridine-Bridged Benzimidazolium Salts: Synthesis, Aggregation, and Application as Phase-Transfer Catalysts (pages 7127–7131)

      Tao Tu, Wilfried Assenmacher, Herwig Peterlik, Gregor Schnakenburg and Karl Heinz Dötz

      Article first published online: 6 AUG 2008 | DOI: 10.1002/anie.200801628

      Thumbnail image of graphical abstract

      Simply structured benzimidazolium salts efficiently gelate a variety of polar organic solvents. π-Stacking, hydrogen bonding, and van der Waals interactions are responsible for the self-assembly process. A packing model is deduced from the single crystal structure of gelator 1. Fiber aggregates of benzimidazolium salts in acetonitrile are efficient phase-transfer catalysts (PTCs) for N-alkylation.

    35. Biotechnology

      Combinatorial Synthesis of Peptide Arrays with a Laser Printer (pages 7132–7135)

      Volker Stadler, Thomas Felgenhauer, Mario Beyer, Simon Fernandez, Klaus Leibe, Stefan Güttler, Martin Gröning, Kai König, Gloria Torralba, Michael Hausmann, Volker Lindenstruth, Alexander Nesterov, Ines Block, Rüdiger Pipkorn, Annemarie Poustka, F. Ralf Bischoff and Frank Breitling

      Article first published online: 31 JUL 2008 | DOI: 10.1002/anie.200801616

      Thumbnail image of graphical abstract

      Special delivery: The “freezing” of activated amino acid derivatives within solid particles enables a laser printer to deliver these “postal packages” to defined locations on a solid support with high resolution. Subsequent parallel coupling is initiated simply by melting a whole layer of 20 different amino acid particles (see schematic representation; Fmoc=9-fluorenylmethoxycarbonyl).

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      Preview: Angew. Chem. Int. Ed. 38/2008 (page 7139)

      Article first published online: 27 AUG 2008 | DOI: 10.1002/anie.200890184

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