Chemistry - A European Journal

Cover image for Vol. 16 Issue 9

March 1, 2010

Volume 16, Issue 9

Pages 2635–2949

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
    1. Cover Picture: Studying the Origin of the Antiferromagnetic to Spin-Canting Transition in the β-p-NCC6F4CNSSN. Molecular Magnet (Chem. Eur. J. 9/2010) (page 2635)

      Mercè Deumal, Jeremy M. Rawson, Andrés E. Goeta, Judith A. K. Howard, Royston C. B. Copley, Michael A. Robb and Juan J. Novoa

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/chem.201090033

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      The sudden variation of the magnetism of the β-p-NCC6F4CNSSN. crystal at 36 K is experimentally known to arise through spin canting. A detailed analysis of the magnetic susceptibility χ(T) reveals a turning point in the residual susceptibility below TN. In their Full Paper on page 2741 ff., M. Deumal, J. J. Novoa et al. analyze this change in χ(T) by performing a first-principles bottom-up study by using crystal data above (160 K) and below (12 K) the magnetic transition temperature.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
    1. Inside Cover: Selective Ruthenium-Catalyzed Alkylation of Indoles by Using Amines (Chem. Eur. J. 9/2010) (page 2636)

      Sebastian Imm, Sebastian Bähn, Annegret Tillack, Kathleen Mevius, Lorenz Neubert and Matthias Beller

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/chem.201090034

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      The borrowing hydrogen methodology is active in the transition-metal-catalyzed C-alkylation of indoles with easily available aliphatic amines. This novel atom efficient and selective method for indole alkylation proceeds in the presence of the Shvo catalyst under basic conditions. It constitutes a complementary and valuable method for alkylations and benzylations. Hence, various substrates, including primary, secondary, and even tertiary amines, react in good to excellent yield with the indoles. For more details see the Communication by M. Beller et al. on page 2705 ff.

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
  4. Corrigendum

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
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  5. News

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
  6. Minireview

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
    1. C[BOND]H Activation

      Functionalization of Organic Molecules by Transition-Metal-Catalyzed C(sp3)[BOND]H Activation (pages 2654–2672)

      Rodolphe Jazzar, Julien Hitce, Alice Renaudat, Julien Sofack-Kreutzer and Olivier Baudoin

      Version of Record online: 8 FEB 2010 | DOI: 10.1002/chem.200902374

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      Breaking strong bonds: This Minireview highlights recent strategies to functionalize alkyl C[BOND]H bonds by transition-metal-catalyzed C[BOND]H activations that involve inner-sphere-type mechanisms. These methods allow the introduction of carbon- or heteroatom-based functional groups and show great promise in the synthesis of complex organic molecules.

      Corrected by:

      Corrigendum: Corrigendum: Functionalization of Organic Molecules by Transition-Metal-Catalyzed C(sp3)[BOND]H Activation

      Vol. 17, Issue 46, 12846, Version of Record online: 4 NOV 2011

  7. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
    1. Rearrangement

      Dimethylcuprate Undergoes a Dyotropic Rearrangement (pages 2674–2678)

      Nicole J. Rijs, Brian F. Yates and Richard A. J. O'Hair

      Version of Record online: 27 JAN 2010 | DOI: 10.1002/chem.200903510

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      All change! Comparison of the gas-phase decomposition reactions of [CH3CuCH3] and [CH3AgCH3] reveals that [CH3CuCH3] undergoes a competition between a dyotropic rearrangement and bond homolysis, whilst [CH3AgCH3] only undergoes bond homolysis. Ab initio calculations reveal that the different behavior in [CH3AgCH3] stems from both the lowering of the homolytic bond dissociation energy and an increase in dyotropic rearrangement activation energy.

    2. Photooxidation

      Photooxidation of N-Confused Porphyrin: A Route to N-Confused Biliverdin Analogues (pages 2679–2682)

      Jacek Wojaczyński and Lechosław Latos-Grażyński

      Version of Record online: 29 JAN 2010 | DOI: 10.1002/chem.200903182

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      Clarity through confusion: The photooxidation of an N-confused porphyrin dianion provides a unique N-confused biliverdin analogue with two types of coordination surroundings: (NNNO) and (CNOO), as demonstrated by a palladium(II) complex (see figure).

    3. Aziridines

      New Arylaziridinyldifluoroborates: Useful Suzuki–Miyaura Reagents (pages 2683–2687)

      Renzo Luisi, Arianna Giovine and Saverio Florio

      Version of Record online: 29 JAN 2010 | DOI: 10.1002/chem.200902056

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      Blossoming promises fruit! A new class of shelf stable organoboron reagents has been obtained from ortho- and laterally lithiated aziridines and benzylamines. Their usefulness as Suzuki–Miyaura reagents has been investigated, proving that they could be fruitful reagents for the preparation of arylated aziridines and benzylamines, even in enantioenriched form, and promising new bifunctional Lewis pairs for catalysis or small-molecule binding.

    4. Asymmetric Synthesis

      The First General, Efficient and Highly Enantioselective Reduction of Quinoxalines and Quinoxalinones (pages 2688–2691)

      Magnus Rueping, Francisco Tato and Fenja. R. Schoepke

      Version of Record online: 5 FEB 2010 | DOI: 10.1002/chem.200902907

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      Simple yet efficient: A series of diverse substituted tetrahydroquinoxalines and dihydroquinoxalinones have been synthesized for the first time in a highly enantioselective fashion (see scheme). Using this metal-free hydrogenation it is possible to isolate these products, which are of high pharmaceutical interest, in good yields and with excellent enantioselectivities in a minimal number of reaction steps.

    5. Combinatorial Chemistry

      Small Molecule Macroarray Construction via Palladium-Mediated Carbon[BOND]Carbon Bond-Forming Reactions: Highly Efficient Synthesis and Screening of Stilbene Arrays (pages 2692–2695)

      Reto Frei and Helen E. Blackwell

      Version of Record online: 4 FEB 2010 | DOI: 10.1002/chem.200903445

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      Arrays of stilbenes have been prepared in high purity by using Heck reactions on planar cellulose support, and demonstrate the compatibility of the small-molecule macroarray platform (see figure) with metal-mediated reactions for the first time. Biological screening of the stilbene library revealed several compounds with the ability to inhibit quorum sensing responses in bacteria, expanding the activity of this compound class.

    6. Synthetic Methods

      Diversity of Products in the Gold-Catalyzed Cyclization of 1-Epoxy-1-alkynylcyclopropanes by Using 1-Oxyallyl Cations (pages 2696–2699)

      Chun-Yao Yang, Min-Shiun Lin, Hsuan-Hung Liao and Rai-Shung Liu

      Version of Record online: 29 JAN 2010 | DOI: 10.1002/chem.200903419

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      A highly stereoselective AuCl3-catalyzed hydrative cyclization of 1-epoxy-1-alkynylcyclopropanes was observed for cis-epoxides. Since this cyclization produced 1-oxyallyl cations efficiently, we accomplished a two-step [4+2] annulation of epoxyalkynes with dienes and enones, to provide complex oxacyclic compounds with excellent diastereoselectivity (see scheme).

    7. Charge Transfer

      Noncovalent Functionalization, Exfoliation, and Solubilization of Graphene in Water by Employing a Fluorescent Coronene Carboxylate (pages 2700–2704)

      Anupama Ghosh, K. Venkata Rao, Subi J. George and C. N. R. Rao

      Version of Record online: 27 JAN 2010 | DOI: 10.1002/chem.200902828

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      Single-layer graphene stabilization: An efficient methodology to make stable aqueous solutions of single-layer graphene has been demonstrated by exploiting charge-transfer interactions with a coronene tetracarboxylate acceptor molecule (see figure). Microscopic studies reveal exfoliation of few-layer graphene and selective stabilization of single-layer graphene in large quantities.

    8. Alkylation

      Selective Ruthenium-Catalyzed Alkylation of Indoles by Using Amines (pages 2705–2709)

      Sebastian Imm, Sebastian Bähn, Annegret Tillack, Kathleen Mevius, Lorenz Neubert and Matthias Beller

      Version of Record online: 29 JAN 2010 | DOI: 10.1002/chem.200903261

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      Lend me your hydrogen! The first transition-metal-catalyzed alkylations of indoles with aliphatic amines proceeding under transfer hydrogenation conditions are developed (see scheme). This reaction is based on the borrowing hydrogen methodology.

    9. DNA Recognition

      Redox-Induced Binding of [(tacn)ReIIBr(CO)2]+ to Guanine, Oligonucleotides, and Peptides (pages 2710–2713)

      Fabio Zobi and Roger Alberto

      Version of Record online: 4 FEB 2010 | DOI: 10.1002/chem.200902760

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      Oxidation is the key: A redox-switch based on a water-soluble ReII complex is presented. Upon binding to biological ligands such as the side chains in peptides or proteins, ReII in, for example, [ReII(tacn)(L)(CO)2]2+ (in wich L=target site, TACN = 1,4,7-triazacyclononane), becomes strongly oxidizing and is reduced to the robust ReI complex [ReI(tacn)(L)(CO)2]+. This reduction leads to essentially irreversible metalation of the biomolecule.

    10. Sensors

      Fluorescent ‘Twist-on’ Sensing by Induced-Fit Anion Stabilisation of a Planar Chromophore (pages 2714–2718)

      Adam N. Swinburne, Martin J. Paterson, Andrew Beeby and Jonathan W. Steed

      Version of Record online: 3 FEB 2010 | DOI: 10.1002/chem.200903293

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      Twist-and-shout: An anion receptor showing a turn-on fluorescence response to chloride ions due to an induced conformational change upon anion binding is reported (see picture).

    11. Bond Theory

      A Definitive Answer to a Bonding Quandary? The Role of One-Electron Resonance Structures in the Bonding of a {Cu3S2}3+ Core (pages 2719–2724)

      John F. Berry

      Version of Record online: 5 FEB 2010 | DOI: 10.1002/chem.200902324

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      Does the complex contain an S[BOND]S bond? This question has been recently debated by Alvarez, who claims that there is no S[BOND]S bond, and Mealli and Hoffmann, who claim there is an S[BOND]S bond. Here, these two opposing viewpoints are reconciled by an in-between alternative for the electronic structure that is supported by DFT calculations and the available experimental data. The compound (see picture) is described as the first that has been recognized to contain the unusual S23− ion, having a three-electron sulfur–sulfur σ bond and an S[BOND]S bond order of 0.5.

  8. Correspondence

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
    1. Bond Theory

      Antiferromagnetism or Delocalized Spin in a Cu3S2 Core? (pages 2726–2728)

      Santiago Alvarez and Eliseo Ruiz

      Version of Record online: 5 FEB 2010 | DOI: 10.1002/chem.200903153

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      Is there a bond or isn′t there? In a further effort to bring light to the debate on the existence of an S[BOND]S bond in Tolman′s cluster compound (shown here), this correspondence is a reply to the preceeding communication.

  9. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Minireview
    8. Communications
    9. Correspondence
    10. Full Papers
    11. Preview
    1. Bioinorganic Chemistry

      Elucidation of Metal-Ion Accumulation Induced by Hydrogen Bonds on Protein Surfaces by Using Porous Lysozyme Crystals Containing RhIII Ions as the Model Surfaces (pages 2730–2740)

      Takafumi Ueno, Satoshi Abe, Tomomi Koshiyama, Takahiro Ohki, Tatsuo Hikage and Yoshihito Watanabe

      Version of Record online: 9 FEB 2010 | DOI: 10.1002/chem.200903269

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      Rhodium and eggs anyone? Dynamic behavior of amino acid residues during the process of accumulation of metal ions (see picture) on a protein surface is directly observed by using X-ray crystal analysis of hen egg white lysozyme porous crystals containing RhIII ions.

    2. Magnetic Properties

      Studying the Origin of the Antiferromagnetic to Spin-Canting Transition in the β-p-NCC6F4CNSSN. Molecular Magnet (pages 2741–2750)

      Mercè Deumal, Jeremy M. Rawson, Andrés E. Goeta, Judith A. K. Howard, Royston C. B. Copley, Michael A. Robb and Juan J. Novoa

      Version of Record online: 5 FEB 2010 | DOI: 10.1002/chem.200903221

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      Spin transitions: The transition from antiferromagnetism to spin canting in the β-p-NCC6F4CNSSN. molecular magnet is investigated by using a first-principles theoretical procedure. Spin canting below 36 K is due to the presence of two ferromagnetic sublattices that are antiferromagnetically coupled (see figure). The evolution of the ferromagnetic JAB contributions explains the change in the slope of the residual χ in the low-temperature region.

    3. Hydrogen Transfer

      Domino Rhodium/Palladium-Catalyzed Dehydrogenation Reactions of Alcohols to Acids by Hydrogen Transfer to Inactivated Alkenes (pages 2751–2757)

      Mónica Trincado, Hansjörg Grützmacher, Francesco Vizza and Claudio Bianchini

      Version of Record online: 15 JAN 2010 | DOI: 10.1002/chem.200903069

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      Acceptable suitors: An improved catalytic system for the dehydrogenative coupling of primary alcohols has been developed by using inactivated alkenes as suitable hydrogen acceptors. The synergic action of homogeneous RhI amide complexes and supported palladium nanoparticles (see picture) as the heterogeneous component of the catalytic system is indicated by a number of experiments.

    4. Anticancer Agents

      Targeting the Hsp90 Chaperone: Synthesis of Novel Resorcylic Acid Macrolactone Inhibitors of Hsp90 (pages 2758–2763)

      James E. H. Day, Swee Y. Sharp, Martin G. Rowlands, Wynne Aherne, Paul Workman and Christopher J. Moody

      Version of Record online: 19 JAN 2010 | DOI: 10.1002/chem.200902766

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      Potential chemotherapeutic agents: A series of resorcylic acid macrolactone analogues of the natural product radicicol (see scheme) has been synthesized; these compounds are inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents.

    5. Zeolites

      Investigation of the Mechanism of Colloidal Silicalite-1 Crystallization by Using DLS, SAXS, and 29Si NMR Spectroscopy (pages 2764–2774)

      Alexander Aerts, Mohamed Haouas, Tom P. Caremans, Lana R. A. Follens, Titus S. van Erp, Francis Taulelle, Jan Vermant, Johan A. Martens and Christine E. A. Kirschhock

      Version of Record online: 13 JAN 2010 | DOI: 10.1002/chem.200901688

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      Fit nanoparticles: Nanoparticles employed in the synthesis of silicalite-1 zeolite undergo differentiation of the silicate framework connectivity and size during the induction stage. Larger nanoparticles (6 nm) with a highly connected silicate framework (see picture; dark-gray particles) are units for nucleation and aggregative crystal growth, whereas smaller nanoparticles (2 nm; see picture; light-gray particles) do not participate in the crystallization.

    6. Antitumor Agents

      Cytotoxic Titanium Salan Complexes: Surprising Interaction of Salan and Alkoxy Ligands (pages 2775–2789)

      Timo A. Immel, Ulrich Groth and Thomas Huhn

      Version of Record online: 26 JAN 2010 | DOI: 10.1002/chem.200902312

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      Size matters: Titanium(IV)salan (ONNO-type) complexes show a surprising size-dependent cytotoxicity in human cancer cells (see figure). A systematic study of more than 40 complexes with various salan and alkoxide ligands revealed the size interdependency of the different ligands. A possible mode of action is proposed based on data from cytotoxicity assays and time-resolved 1H NMR spectroscopy studies.

    7. Host–Guest Interactions

      Sugar-Decorated Sugar Vesicles: Lectin–Carbohydrate Recognition at the Surface of Cyclodextrin Vesicles (pages 2790–2796)

      Jens Voskuhl, Marc C. A. Stuart and Bart Jan Ravoo

      Version of Record online: 22 JAN 2010 | DOI: 10.1002/chem.200902423

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      Sweeter than sweet: An artificial glycocalix self-assembles when carbohydrate ligands decorate a carbohydrate vesicle (see figure).

    8. Axial Chirality

      Resolution of the First Nonracemic Diquats (pages 2797–2805)

      Jérôme Vachon, Gérald Bernardinelli and Jérôme Lacour

      Version of Record online: 22 JAN 2010 | DOI: 10.1002/chem.200902562

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      Tricyclic eight-membered ring diquats were prepared and shown to be the first configurationally stable derivatives of their kind. Resolution was achieved by using chiral BINPHAT and TRISPHAT anions. Their absolute configuration was unambiguously determined by X-ray analysis and circular dichroism (CD). These derivatives are the first stable eight-membered-ring derivatives with only three ring constraints (see figure).

    9. Asymmetric Organocatalysis

      The Brønsted Acid Catalyzed, Enantioselective Vinylogous Mannich Reaction (pages 2806–2818)

      Marcel Sickert, Falko Abels, Matthias Lang, Joachim Sieler, Claudia Birkemeyer and Christoph Schneider

      Version of Record online: 22 JAN 2010 | DOI: 10.1002/chem.200902537

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      A good Mannich is hard to find: The first catalytic, enantioselective, vinylogous Mannich reaction of acyclic silyl dienolates 1 has been developed. It furnishes δ-amino α,β-unsaturated esters 3 in excellent yields and up to 97 % ee (see scheme). Phosphoric acid 2 with a 2,2′-dihydroxy-1,1′-binaphthyl (BINOL) backbone was established as the optimal chiral Brønsted acid.

    10. Ligand Design

      A New Synthesis of Charge-Neutral Tris-Pyrazolyl and -Methimazolyl Borate Ligands (pages 2819–2829)

      Philip J. Bailey, Laura Budd, Filipa A. Cavaco, Simon Parsons, Felix Rudolphi, Alejandro Sanchez-Perucha and Fraser J. White

      Version of Record online: 27 JAN 2010 | DOI: 10.1002/chem.200902763

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      Nitrogen to neutrality: The substitution of HNMe2 in [(HNMe2)B(azolyl)3] (azolyl=pyrazolyl, methimazolyl) by a range of N-donor ligands provides a high-yielding route to neutral tripodal ligands (see scheme). The IR spectra of MnI–tricarbonyl complexes of the ligands allow comparison of their donor properties with the anionic parent ligands.

    11. Donor–Acceptor Systems

      Vectorial Electron Transfer in Donor–Photosensitizer–Acceptor Triads Based on Novel Bis-tridentate Ruthenium Polypyridyl Complexes (pages 2830–2842)

      Rohan J. Kumar, Susanne Karlsson, Daniel Streich, Alice Rolandini Jensen, Michael Jäger, Hans-Christian Becker, Jonas Bergquist, Olof Johansson and Leif Hammarström

      Version of Record online: 19 JAN 2010 | DOI: 10.1002/chem.200902716

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      Defining directions: The octahedral bis-2,6-di(quinolin-8-yl)pyridine ruthenium(II) complex shows an excited-state lifetime of 3 μs. Its potential for light-harvesting applications is exemplified in rodlike donor–photosensitizer–acceptor (D-P-A) assemblies with this motif (see picture). The D2-symmetric bis-tridentate photosensitizer unit gives the triads as single, linear isomers that display vectorial electron transfer.

    12. Mesoporous Materials

      Synthesis of Superacid-Functionalized Mesoporous Nanocages with Tunable Pore Diameters and Their Application in the Synthesis of Coumarins (pages 2843–2851)

      Pranjal Kalita, B. Sathyaseelan, Ajayan Mano, S. M. Javaid Zaidi, Murugulla A. Chari and Ajayan Vinu

      Version of Record online: 19 JAN 2010 | DOI: 10.1002/chem.200902531

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      Nanocage superacids: Here we demonstrate for the first time the preparation and characterization of a highly stable, superacid-functionalized, well-ordered 3D-nanocage material with tunable pore diameters that shows superior performance in the synthesis of coumarin derivatives over zeolites and metal-substituted mesoporous catalysts (see figure).

    13. Spiro Compounds

      Organocatalytic Tandem Reaction to Construct Six-Membered Spirocyclic Oxindoles with Multiple Chiral Centres through a Formal [2+2+2] Annulation (pages 2852–2856)

      Kun Jiang, Zhi-Jun Jia, Shi Chen, Li Wu and Ying-Chun Chen

      Version of Record online: 28 JAN 2010 | DOI: 10.1002/chem.200903009

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      Construction of complexity: An efficient one-pot, three-component tandem reaction for the asymmetric synthesis of six-membered spirocyclic oxindoles with a formal [2+2+2] annulation was developed. The Michael addition of aliphatic aldehydes to electron-deficient olefinic oxindoles gave chiral C3 components (see scheme; Boc: tert-butoxycarbonyl; TMS: trimethylsilyl), which combined with electrophiles to afford substituted spirocyclic oxindoles.

    14. Diphosphines

      Towards Spontaneous Heterolysis of the Homonuclear P[BOND]P Bond in Diphosphines: The Case of Diazaphospholeniumtriphospholides (pages 2857–2865)

      Zoltán Benkő, Sebastian Burck, Dietrich Gudat, Martin Hofmann, Falk Lissner, László Nyulászi and Ulrich Zenneck

      Version of Record online: 22 JAN 2010 | DOI: 10.1002/chem.200902931

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      Contact ion pairs: The molecular structures of diazaphospholenium triphospholides are best described in terms of contact ion pairs with a polarized P(+)P(−) arrangement, rather than as molecular diphosphines with a covalent P[BOND]P bond (see figure). The polarization can be traced to a combination of electronic and steric factors, so that these compounds could be considered as special cases of frustrated Lewis pairs.

    15. Main Group Chemistry

      Stable N-Heterocyclic Carbene Adducts of Arylchlorosilylenes and Their Germanium Homologues (pages 2866–2872)

      Alexander C. Filippou, Oleg Chernov, Burgert Blom, Kai W. Stumpf and Gregor Schnakenburg

      Version of Record online: 14 JAN 2010 | DOI: 10.1002/chem.200903019

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      The first monomeric arylsilicon(II) chlorides, SiArCl(Im-Me4), are reported in which Ar is C6H3-2,6-Mes2 (Mes=C6H2-2,4,6-Me3) or C6H3-2,6-Trip2 (Trip=C6H2-2,4,6-iPr3)] and Im-Me4 is the N-heterocyclic carbene 1,3,4,5-tetramethylimidazol-2-ylidene. Their molecular (see picture) and electronic structures are compared with those of the homologous germanium compounds.

    16. Medium-Sized Rings

      Intermolecular Photocyclizations of N-(ω-Hydroxyalkyl)tetrachlorophthalimide with Alkenes Leading to Medium- and Large-Ring Heterocycles—Reaction Modes and Regio- and Stereoselectivity of the 1,n-Biradicals (pages 2873–2886)

      Yong-Miao Shen, Xiao-Liang Yang, Da-Qing Chen, Jie Xue, Liang Zhu, Hoong-Kun Fun, Hong-Wen Hu and Jian-Hua Xu

      Version of Record online: 19 JAN 2010 | DOI: 10.1002/chem.200902849

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      Get triplet 1,n-biradicals! A new strategy for photocyclizations and for generating triplet 1,n-biradicals (see scheme) by intermolecular photoreactions of N-(ω-hydroxyalkyl)tetrachlorophthalimides with alkenes provides direct verification to possible reaction pathways of the 1,n-biradicals and gives a new insight into the factors deciding reaction-pathway competition and reaction stereoselectivity.

    17. Fluorescent Probes

      Dihydronaphthalene-Fused Boron–Dipyrromethene (BODIPY) Dyes: Insight into the Electronic and Conformational Tuning Modes of BODIPY Fluorophores (pages 2887–2903)

      Yan-Wei Wang, Ana B. Descalzo, Zhen Shen, Xiao-Zeng You and Knut Rurack

      Version of Record online: 26 JAN 2010 | DOI: 10.1002/chem.200902527

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      Straightjacketing BODIPYs: Forcing the boron–dipyrromethene (BDP, BODIPY) chromophore into a sterically highly constrained conformation by attachment of rigid dihydronaphthalene extensions to the dipyrrin core (see figure) allows specific adjustment of the optical properties of the dyes. This paper sketches the possibilities of BODIPY tuning.

    18. Redox Chemistry

      Redox Reaction of the Pd0 Complex Bearing the Trost Ligand with meso-Cycloalkene-1,4-biscarbonates Leading to a Diamidato PdII Complex and 1,3-Cycloalkadienes: Enantioselective Desymmetrization Versus Catalyst Deactivation (pages 2904–2915)

      Vasily N. Tsarev, Dennis Wolters and Hans-Joachim Gais

      Version of Record online: 26 JAN 2010 | DOI: 10.1002/chem.200902739

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      Desymmetrization versus deactivation: The Pd0/Trost ligand complex and allylic 1,4-biscarbonates undergo a facile redox reaction with the formation of a diamidato PdII complex and 1,3-dienes. The catalytic desymmetrization of the meso-biscarbonate with the Pd0/Trost ligand complex and HCO3 delivers, with high enantioselectivity, the corresponding alcohol and/or bicyclic carbonate (see scheme). The Pd0/Trost ligand complex is stable in the absence of dioxygen.

    19. Molecular Recognition

      Squaraine Rotaxane as a Reversible Optical Chloride Sensor (pages 2916–2921)

      Jeremiah J. Gassensmith, Sarah Matthys, Jung-Jae Lee, Aleksandra Wojcik, Prashant V. Kamat and Bradley D. Smith

      Version of Record online: 15 JAN 2010 | DOI: 10.1002/chem.200902547

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      Seeing is believing: Cl binding to the interlocked [2]rotaxane induces macrocycle translocation away from the squaraine station and a reversible increase in red fluorescence emission (such as that depicted). Immobilization of the rotaxane sensor creates a prototype dipstick system for fluorometric and naked-eye colorimetric detection of Cl in aqueous solution.

    20. Glycolipids

      The Structure of a Novel Neutral Lipid A from the Lipopolysaccharide of Bradyrhizobium elkanii Containing Three Mannose Units in the Backbone (pages 2922–2929)

      Iwona Komaniecka, Adam Choma, Buko Lindner and Otto Holst

      Version of Record online: 19 JAN 2010 | DOI: 10.1002/chem.200902390

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      Lipid A structure: The chemical structure of lipid A isolated from Bradyrhizobium elkanii has been established (see scheme). The backbone is composed of 2,3-dideoxy-2,3-diamino-D-glucopyranose disaccharide substituted by three mannose units. It contains 12:0(3-OH) and 14:0(3-OH) as amide-linked fatty acids and two long (ω-1)-ester-linked hydroxylated fatty acids with 25–33 carbon atoms. One of the acyloxyacyl residues can be further acylated by 3-hydroxybutyric acid.

    21. Luminescence

      Highly Uniform YBO3 Hierarchical Architectures: Facile Synthesis and Tunable Luminescence Properties (pages 2930–2937)

      Guang Jia, Hongpeng You, Kai Liu, Yuhua Zheng, Ning Guo, Junjiao Jia and Hongjie Zhang

      Version of Record online: 27 JAN 2010 | DOI: 10.1002/chem.200902834

      Thumbnail image of graphical abstract

      Micropancakes: Highly uniform and well-dispersed YBO3 hierarchical architectures with a pancake-like shape have been successfully prepared by a hydrothermal conversion method (left image). The luminescence colors of the YBO3 samples co-doped with Eu3+ and Tb3+ can be tuned from red, through yellow and green-yellow, to green by simply adjusting the relative doping concentrations of the activator ions (right image).

    22. Protecting Groups

      2,2-Bis(ethoxycarbonyl)vinyl (BECV) as a Versatile Amine Protecting Group for Selective Functional-Group Transformations (pages 2938–2943)

      Andivelu Ilangovan and Rajendran Ganesh Kumar

      Version of Record online: 14 JAN 2010 | DOI: 10.1002/chem.200902054

      Thumbnail image of graphical abstract

      A simple and selective amine protecting group is described using 2,2-bis(ethoxycarbonyl)vinyl- (BECV). The method provides a simple way for the conversion of amino acids in to amino esters under very mild conditions, and is also compatible with several functional-group transformations on anilines and aliphatic amines.

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      Preview: Chem. Eur. J. 10/2010 (page 2949)

      Version of Record online: 19 FEB 2010 | DOI: 10.1002/chem.201090038

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