Angewandte Chemie International Edition in English

Cover image for Vol. 35 Issue 3

February 16, 1996

Volume 35, Issue 3

Pages 231–347

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1996)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199602291

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      The cover picture shows schematically how leukocytes from the blood stream bind to activated endothelium during inflammation processes and are finally extravasated into the surrounding tissue. The first step is the interaction of glycoproteins on leukocytes with adhesion molecules on the endothelium (P-, E-selectin). The tetrasaccharide sialyl Lewisx has been identified as the binding epitope in complex glycoproteins, which are bound through carbohydrates to the selectins. Trivalent glycopeptides like that in the middle of the picture, which present three sialyl Lewisx units, were synthesized by H. Kunz et al. with the goal of achieving improved receptor affinity. The authors describe the results of the adhesion tests and the synthesis of the glycopeptides on pages 321 – 324.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Stereocontrol in Organic Synthesis Using the Diphenylphosphoryl Group (pages 241–270)

      Dr. Jonathan Clayden and Dr. Stuart Warren

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199602411

      Still more can be expected from the Horner–Wittig reaction. Not only regioselective but also stereoselective Horner–Wittig additions and eliminations are possible with the bulky, anion-stabilizing Ph2PO group. For example, alkenes having chiral centers on opposite ends of stereochemically defined double bonds can be constructed. Decisive advantages in these syntheses: Ph2PO compounds are simple to purify, and diastereomeric β-hydroxy phosphane oxide adducts are easily separated.

    2. Metallophosphaalkenes—from Exotics to Versatile Building Blocks in Preparative Chemistry (pages 271–288)

      Prof. Dr. Lothar Weber

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199602711

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      Cycloadditions and cyclooligomerizations are two of the reaction types that are possible with metallophosphaalkenes. The five modes of metalation in these compounds can be described by I[BOND]V. Syntheses, structures, and reactivity of these molecules, which are also versatile ligands, are presented herein.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Pericyclic Reactions in Biological Systems—Does Nature Know About the Diels—Alder Reaction? (pages 289–291)

      Dr. Sabine Laschat

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199602891

      Not only synthetic chemists, but also nature makes use of the spontaneous Diels-Alder reaction. Now there is also increasing evidence for a Diels–Alder-ase, for example in the biosynthesis of solanapyrones. The search for an enzyme-catalyzed [4 + 2]cycloaddition in nature will therefore certainly continue.

    2. Boron-Substituted Heterocycles as π-Donors in Organometallic Chemistry—A Sandwich Complex with 1-H-Boratabenzene and Lithium (pages 292–293)

      Prof. Dr. H. Nöth and Dr. Martin Schmidt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199602921

      New impetus both for the organometallic chemistry of alkali metals as well as for organoboron chemistry should be stimulated by the synthesis of 1 by Fu et al. Though this compound is the second complex containing a hydrogen atom on the boron atom of boratabenzene, it is the first that has been characterized by X-ray structural analysis.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Synthesis and Structure of the First Cyclopentadienyl(halogeno)metal(VI) Complex of the Chromium Triad [((η5-C5Me5)WF5)] (pages 295–297)

      Dr. Katrin Köhler, Dr. Axel Herzog, Dr. Alexander Steiner and Prof. Dr. Herbert W. Roesky

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199602951

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      Tetrafluoride 1, pentafluoride 2, and fluoride dioxide 3 can be obtained from [Cp*WCl4] and Me3SnF according to the reaction scheme shown below. Complexes of type 2 were hitherto not obtainable with chromium, molybdenum, and tungsten. The structure analysis of 2 revealed that the W center is in a square-bipyramidal environment and that the compound exists as a monomer.

    2. A Freely Hinged Macrotricycle with a Molecular Cavity (pages 297–299)

      Dr. Ziyan Wu and Prof. Jeffrey S. Moore

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199602971

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      The connectivity of a finite fragment of the prototypical silicon network of the intermetallic compound α-ThSi2 is represented by the carbon-rich macrotricycle 1. The compound has a cavity with dimensions of 36 × 12 × 12 Å3. Calculations indicate that concerted torsional rotation around the parallel lateral bonds results in collapse to a nearly planar, folded structure. The flexibility of compounds like 1 single them out as promising building blocks for the preparation of auxetic materials.

    3. Tris(chalcogenato)carbenium Ions [C(XR)3]+ (X [DOUBLE BOND] O, S, Se, Te): An Experimental and Quantum-Chemical Comparison (pages 300–303)

      Dietmar Ohlmann, Christina M. Marchand, Prof. Dr. Hansjörg Grützmacher, Grace Shiahuy Chen, David Farmer, Prof. Dr. Rainer Glaser, Antonio Currao, Prof. Dr. Reinhard Nesper and Dr. Hans Pritzkow

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603001

      [C(OR)3]+ ions are stabilized differently than [C(XR)3]+ ions (X = S, Se, Te). While the stability of the RO-substituted carbenium ions can be attributed to the high polarity of the Cδ+ -Oδ− bond, the polarity of the C-X bond in the homologous S-, Se-, and Te-containing ions is reversed, and the stabilization is achieved by the σ-and π-dative effect of the chalcogen centers. These results were obtained by ab initio calculations on [C(XH)3]+ ions and by experimental studies on the new compounds [C(XR)3][PF6] (X = S, Se, Te; R = 2,4,6-iPr3C6H2).

    4. Conformational Differences of O- and C-Glycosides in the Protein-Bound State: Different Conformations of C-Lactose and Its O-Analogue are Recognized by Ricin B, a Galactose-Binding Protein (pages 303–306)

      Juan-Félix Espinosa, Dr. F. Javier Cañada, Dr. Juan Luis Asensio, Dr. Hansjörg Dietrich, Prof. Dr. Manuel Martín-Lomas, Prof. Dr. Richard R. Schmidt and Dr. Jesús Jiménez-Barbero

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603031

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      NMR experiments provide evidence that C- and O-glycosides such as 1 and 2, respectively, are not necessarily bound in the same conformation by a protein. A projection of the conformations of 1 and 2 recognized by ricin B is shown on the lower right.

    5. Catenane Chameleons: Environment-Sensitive Translational Isomerism in Amphiphilic Benzylic Amide [2]Catenanes (pages 306–310)

      Dr. David A. Leigh, Karen Moody, Dr. John P. Smart, Dr. Karen J. Watson and Alexandra M. Z. Slawin

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603061

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      Intramolecular double bifurcated hydrogen bonding is responsible for the preferred conformation I of the catenane shown below in the solid state and in nonpolar solvents; in polar solvents competitive hydrogen bonding and polarphobic forces leads to conformation II.

    6. A Chelating Triscarbene Ligand and Its Hexacarbene Iron Complex (pages 310–312)

      Dr. Ulrich Kernbach, Dr. Matthias Ramm, Prof. Dr. Peter Luger and Prof. Dr. Wolf P. Fehlhammer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603101

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      A free tricarbene is most likely a long-lived intermediate in the formation of the first hexacarbene iron complex 1 (R = Me) from trimethylated tris(1-imidazolyl)borate, n-butyllithium, iron chloride, and tetraphenylborate. This tripodal C,C′,C″-chelating ligand, for which the authors predict a brilliant future, is an isomer of Trofimenko's tris(1-pyra-zolyl)borate and represents a novel class of negatively charged six-electron donors with the greatest possible similarity to the cyclopentadienyl anion.

    7. Synthesis, Structure, and Reactivity of a 2,3,4-Triphosphapentadienide (pages 313–315)

      Dipl.-Chem. Vera Thelen, Dr. Dietmar Schmidt, Dr. Martin Nieger, Prof. Dr. Edgar Niecke and Prof. Dr. Wolfgang W. Schoeller

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603131

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      Three two-coordinate phosphorus atoms are present in the W-shaped 2,3,4-triphos-phapentadienide 3, which is obtained as a lithium salt from the reaction of the phosphaalkene 1 with 2 (R = SiMe3). Heterocycles and heterobicycles containing three phosphorus atoms are accessible from 3.

    8. Reactivity of Tungstenocene with B[BOND]B and B[BOND]H Bonds versus C[BOND]H Bonds (pages 315–317)

      Prof. John F. Hartwig and Dr. Xiaoming He

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603151

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      The selectivity for addition of the B[BOND]B bond of Cat'BBCat' (Cat' = 4-tBuC6H3O2) to [Cp2W] even in the presence of reactive C[BOND]H bonds in the solvent benzene is remarkable. In contrast to facile B[BOND]B cleavage, B[BOND]H bond formation occurred upon photolysis of [Cp2W(H)(BCat)] (Cat = C6H4O2). This facile cleavage of B[BOND]B bonds and the preferred formation of B[BOND]H bonds contrasts with the typical selectivities for C[BOND]C and C[BOND]H activation reactions. The formation and some reactions of tungstenocene are shown on the right.

    9. Specific Protein Docking to Chelator Lipid Monolayers Monitored by FT-IR Spectroscopy at the Air–Water Interface (pages 317–320)

      Dipl.-Chem. Lutz Schmitt, Dr. Tom M. Bohanon, Dipl.-Chem. Steffen Denzinger, Prof. Dr. Helmut Ringsdorf and Dr. Robert Tampé

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603171

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      A novel class of chelator lipids combines the fundamental properties of self-assembly with protein engineering techniques, leading to well-organized biofunctionalized interfaces and two-dimensional protein arrays. Reflection FT-IR spectroscopy at the air - water interface was used to monitor the formation of a metal-sensitive lipid film as well as the reversible and specific docking (represented on the right) of a fusion protein (B) to this chelator lipid layer through a histidine tag (A).

    10. The Crystal Structure of Difluoroamine (page 320)

      Dipl.-Chem. Martin Frank Klapdor, Prof. Dr. Helge Willner, Dr. Wolfgang Poll and Prof. Dr. Dietrich Mootz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603201

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      Potentially explosive difluoroamine, HNF2, which is gaseous under normal conditions, is associated in the solid state through N[BOND]HċN hydrogen bonds[BOND]and not N[BOND]HċF bonds[BOND]to form infinite zigzag chains. The results of the X-ray structure analysis are consistent with those of earlier spectroscopic findings and theoretical calculations.

    11. Multiple Sialyl Lewisx N-Glycopeptides: Effective Ligands for E-Selectin (pages 321–324)

      Dipl.-Chem. Ulrich Sprengard, Dr. Manfred Schudok, Dr. Wolfgang Schmidt, Dr. Gerhard Kretzschmar and Prof. Dr. Horst Kunz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603211

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      Threefold condensation of the sialyl Lewisx amine derivative 1 with cyclopeptides leads to multivalent glycopeptides with repetitive saccharide units. A trivalent sialyl Lewisx N-glycopeptide proved to be a potent antagonist of E-selectin.

    12. Synthesis and Dynamic Behavior of the Heptafluorotrisilacyclohexane Anion: A New Fluxional Silicate with Rapid Intramolecular Exchange of Fluoride Ligand (pages 324–326)

      Dalci Brondani, Francis H. Carré, Prof. Dr. Robert J. P. Corriu, Prof. Dr. Joel J. E. Moreau and Michel Wong Chi Man

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603241

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      Chair inversions and F[BOND]Si migrations can explain why in solution the trisilacyclohexane anion 1 provides only one 19F and one 29Si NMR signal. The ion shows fluxional behavior in the crystal as well, as is confirmed by the 29Si CP/MAS NMR spectrum at 298 K, which contains only one signal.

    13. A Reversible Transition between an α-Helix and a 310-Helix in a Fluorescence-Labeled Peptide (pages 326–329)

      Dr. Graham Hungerford, Marta Martinez-Insua, Prof. David J. S. Birch and Dr. Barry D. Moore

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603261

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      Two well-defined, interconvertible helical states are distinguishable by CD and fluorescence spectroscopy in a synthetic peptide containing both electron donor (D) and acceptor (A) units (shown schematically below). This provides a suitable model system for a molecular switch, regulated by conformational changes, with potential applications in molecular electronics.

    14. Stable, Highly Unsaturated Glycerides—Enzymatic Synthesis with a Carotenoic Acid (pages 329–330)

      Dr. Vassilia Partali, Dr. Lise Kvittingen, Dr. Hans-Richard Sliwka and Dr. Thorleif Anthonsen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603291

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      The first stable, highly unsaturated fat! Previous attempts at the synthesis of these compounds had led to rather unstable compounds without practical application; however, the use of a carotenoid as fatty acid has resulted in stable, conjugated polyene glycerides such as 1.

    15. Synthesis of Tailor-Made Glycoconjugates Showing AT III-Mediated Inhibition of Blood Coagulation Factors Xa and Thrombin (pages 331–333)

      Dr. Pieter Westerduin, Jan E. M. Basten, Marc A. Broekhoven, Vera de Kimpe, Dr. Ir. Will H. A. Kuijpers and Prof. Dr. Constant A. A. van Boeckel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603311

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      A sufficiently long spacer between the antithrombin- and thrombin-binding domains (ABD and TBD, respectively) is necessary to impart antithrombin activity to a synthetic glycoconjugate (shown schematically below). The spacer need not consist of multiple sugar units as in heparin; a simple chain about 50 atoms in length suffices. In addition, varying the charge density of the TBD affects the inhibitor activity, and symmetric glycoconjugates (TBD = ABD) also display high antithrombin activities.

    16. (15 R)-16-m-Tolyl-17,18,19,20-tetranorisocarbacyclin: A Stable Ligand with High Binding Affinity and Selectivity for a Prostacyclin Receptor in the Central Nervous System (pages 334–336)

      Prof. Dr. Masaaki Suzuki, Koichi Kato, Prof. Dr. Ryoji Noyori, Dr. Yumiko Watanabe, Dr. Hajime Takechi, Dr. Kiyoshi Matsumura, Prof. Dr. Bengt Långström and Dr. Yasuyoshi Watanabe

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603341

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      Structural modification of the prostacyclin agonist isocarbacyclin resulted in the stable, highly selective ligand 1, which displays high binding affinity for a prostacyclin receptor in the central nervous system. The binding profile of 1 thus contrasts markedly with those of cicaprost and iloprost.

    17. Supramolecular Catalysis of H/D Exchange in Malonate Ions by Macrocyclic Polyamines: A Model Enzyme with Enolase Activity (pages 337–339)

      Hicham Fenniri, Prof. Dr. Jean-Marie Lehn and Dr. Annie Marquis-Rigault

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603371

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      In three ways at once the macrocyclic polyamine [24]aneN6O2 promotes the H/D exchange at the α position in malonate ions: The quadruply protonated species in neutral pH range forms a quite stable dicationic complex (1) with the malonate dianion, which facilitates the approach of a base and assists the enolization through the acidic NH+ centers. The acceleration factor for the fourfold protonated polyamine [24]aneN6O2 is kcat/kuncat ≈ 1.4 × 103.

    18. Effects of Strained Bicyclic Annelation on the Benzene Nucleus: The X-Ray Crystal Structures of a Triphenylene and Two Anthracene Derivatives (pages 339–341)

      Francesca Cardullo, Dr. Daniele Giuffrida, Prof. Franz H. Kohnke, Françisco M. Raymo, Prof. J. Fraser Stoddart and Dr. David J. Williams

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603391

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      Pronounced bond length alternation in the central aromatic ring is the eye-catching structural feature of triepoxytriphenylene 1. By contrast, no significant bond length alternation is observed in the linearly bisannelated compounds 2 and 3. The key difference is ascribed to the position of annelations with the bicyclic units.

    19. Asymmetric Catalysis in the Complexation of Prochiral Dienes by the Tricarbonyliron Fragment: A Novel Methodology for the Enantioselective Synthesis of Planar Chiral Tricarbonyl(diene)iron Complexes (pages 341–344)

      Prof. Dr. Hans-Joachim Knölker and Dipl.-Chem. Holger Hermann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603411

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      The asymmetric catalytic Fe(CO)3 complexation of a prochiral ligand is achieved for the first time. The preparation of different enantiopure 1-aza-1,3-butadiene catalysts and their application to the enantioselective synthesis of optically active, planar, chiral transition metal π complexes is reported [Eq. (a)].

  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Book Review: Dictionary of Gene Technology. By G. Kahl (page 345)

      Michael Meisterernst

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199603451