Angewandte Chemie International Edition in English

Cover image for Vol. 30 Issue 12

December 1991

Volume 30, Issue 12

Pages 1531–1749

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 12/1991)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199115311

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      The title picture shows in the center a computed ball-and-stick model of methyltrioxorhenium (MTO), photographed hot off the screen! This readily accessible organometal oxide is easy to purify, stable well above its melting point, soluble in organic solvents and water (without decomposition), and stable in acid and in air. Add to these excellent chemical properties exceptional catalytic qualities. MTO supported on A12O3 catalyzes olefin metathesis and ring-opening metathetical polymerization (reactions depicted at the top and bottom of the cover picture, respectively), but also the epoxidation of olefins with H2O2 (right) and the synthesis of olefins from aldehydes and diazoalkanes (left). More on this impressive catalyst is to be found in three communications by W. A. Herrmann et al. on p. 1636ff.

    2. Graphical Abstract (Angew. Chem. Int. Ed. Engl. 12/1991)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199115312

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Corrigenda
    5. Author Index
    6. Subject Index
    1. New Approaches to the Use of Amino Acids as Chiral Building Blocks in Organic Synthesis [New Synthetic Methods (85)] (pages 1531–1546)

      Prof. Dr. Manfred T. Reetz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199115313

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      The synthetic potential of the amino acids seems simply inexhaustible! The α-amino acids protected at nitrogen can be transformed into the corresponding α-amino aldehydes without racemization. The correct choice of protecting group (“protecting-group tuning”) such as two benzyl residues on the nitrogen atom allows for the first time Grignard-like reactions, aldol and Me3SiCN additions, and hetero-Diels-Alder reactions with high nonchelate control. The Wittig reaction transforms the α-amino aldehydes into eletron-poor γ-amino olefins, which in turn undergo cuprate, Michael, and cycloadditions. The reaction 1 [RIGHTWARDS ARROW] 2 + 3 is an example.

    2. Volume Effect or Paddle-Wheel Mechanism—Fast Alkali-Metal Ionic Conduction in Solids with Rotationally Disordered Complex Anions (pages 1547–1558)

      Prof. Dr. Martin Jansen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199115471

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      Transport phenomena in the solid state are as important for basic research as for applications. In particular the potential of the “fast” ion conductors attract attention. On the basis of ionic crystals in which high charge-carrying oncentrations (point defects in the cationic substructure) can be introduced on one hand, and the activation energy of site-interchange lowered by translationally fixed but rotationally mobile complex anions on the other, alkali-metal ionic conductors with a high conductivity can be synthesized. The picture shows a section of the crystal structure of the high-temperature form of Na3NO3 ([TRIPLE BOND](NO2)ONa3).

    3. 1,4-Dihydropyridines: Effects of Chirality and Conformation on the Calcium Antagonist and Calcium Agonist Activities (pages 1559–1578)

      Dr. Siegfried Goldmann and Jürgen Stoltefuss

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199115591

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      The therapy for cardiac disease is practically inconceivable these days without 1,4-dihydropyridine derivatives. They can function as calcium antagonists or as calcium agonists, that is, they inhibit or promote the transport of Ca2+ ions into heart and blood-vessel muscles. The particular effect depends on the configuration of the total molecule and the pattern of substitution at the pyridine ring. The sketch to the right summarizes the salient structural features required for an efficient binding of a typical calcium antagonist to the receptor. The exchange of the ester group on the left for a nitro group reverses the pharmacological function.

    4. Silicon Nitride—From Powder Synthesis to Ceramic Materials (pages 1579–1597)

      Dr. Horst Lange, Dr. Gerhard Wötting and Prof. Dr. Gerhard Winter

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199115791

      Not as raw material for the production of ammonia, as suggested at the turn of the century, but as a highly resilient material, silicon nitride is attracting interest. Today it is used for the construction of chemical apparatus, for applications where corrosion- and wear-resistance is essential, in energy technology, in metal finishing, and particularly as material for engines and turbines. The chemical reactions that form the basis of the preparation of Si3N4, the factors affecting the properties of the material, and the course of the technical process are covered in this review.

    5. Routes to New Aromatic Polycarbonates with Special Material Properties (pages 1598–1610)

      Dr. Dieter Freitag, Dr. Gerd Fengler and Dr. Leo Morbitzer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199115981

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      How the chemical and physical potential of the polycarbonates can be optimally exploited to produce high-performance plastics is described in this review. Important design principles, starting with the standard polycarbonate 1, are incorporation of other monomers or end groups, creation of branching, doping with additives, and formation of blends with other thermoplastics.

    6. Glycolipids as Immunomodulators: Syntheses and Properties (pages 1611–1620)

      Dr. Oswald Lockhoff

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116111

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      An increase in the specific immune response is stimulated by novel glycolipid analogues of the type BAY R 1005 (1). These are both locally and systemically well tolerated; their mode of action, which differs from that of the known adjuvants, suggests that they are particularly promising for immunizing patients with defective T-lymphocyte functions, for example AIDS patients.

    7. Herbicides in Photosynthesis Research (pages 1621–1633)

      Dr. Wilfried Draber, Dr. Klaus Tietjen, Dr. Joachim F. Kluth and Prof. Dr. Achim Trebst

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116211

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      A protein subunit of photosystem 11, the D 1 protein, is the specific site of attack for photosynthesis-inhibiting herbicides in plants. Just how precisely the mode of binding is known is shown on the right for an example, namely terbutryn, a 1,3,5-triazine derivative. The proposed interaction is based on studies of herbicide-tolerant mutants, on the use of techniques such as photoaffinity labeling, and on the close structural analogy between plant and bacterial photosystems. In this case even similarities in the interaction of the inhibitor with specific amino acids in the binding pocket are evident.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Corrigenda
    5. Author Index
    6. Subject Index
    1. Diastereomer Separation by Formation of Inclusion Compounds: 2,6-Dimethylnaphthalene Complexes of Flumethrin (pages 1634–1636)

      Dr. Liborius Born and Dr. Ruiner Fuchs

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116341

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      The separation of the inactive flumethrin isomer from a technical mixture of this insecticide and acaricide was achieved by forming an inclusion complex. The composition of the commercial formulation can thus be enriched in the active diastereomer and dosages can be reduced. X-ray crystallography reveals that adducts of type 1 are formed. Electron donor–acceptor interactions are probably the controlling factor in the formation of 1.

    2. Methyltrioxorhenium as Catalyst for Olefin Metathesis (pages 1636–1638)

      Prof. Dr. Wolfgang A. Herrmann, Dr. Werner Wagner, Uwe N. Flessner, Ursula Volkhardt and Dr. Hartmut Komber

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116361

      No cocatalysts are needed as additives when methyltrioxorhenium (MTO) supported on acidic carriers is employed to catalyze the metathesis of functionalized olefins. A typical system is MTO/Al2O3−SiO2, which is active, for instance, in the metathesis of ally1 halides, allylsilanes, unsaturated carboxylates, and nitriles. MTO in combination with RnAlCl3-n is a homogeneous catalyst in ring-opening polymerizations (R[DOUBLE BOND]CH3, C2H5; n = 1,2).

    3. Methyltrioxorhenium as Catalyst for Olefin Oxidation (pages 1638–1641)

      Prof. Dr. Wolfgang A. Herrmann, Richard W Fischer and Dr. Dieter W. Marz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116381

      The pronounced Lewis acidity explains the exceptional activity of the title compound as catalyst for olefin epoxidations with hydrogen peroxide. The system MTO/tBuOH/H2O2 transforms olefins selectively and efficiently into epoxides under very mild conditions (−30 to + 60°C, but normally at room temperature). In general, 0.1 to 1 mol% MTO is sufficient to achieve high turnovers. Variation of the alkyl group and addition of cocatalysts (e.g. amines) should influence activity and stereoselectivity.

    4. Methyltrioxorhenium as Catalyst of a Novel Aldehyde Olefination (pages 1641–1643)

      Prof. Dr. Wolfgang A. Herrmann and Dr. Mei Wang

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116411

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      From aldehydes or cyclic ketones, diazoalkanes, and tertiary phosphanes, olefins may be prepared according to Equation (a) with MTO as catalyst. In particular, diazoacetates and -malonates (R2, R3[DOUBLE BOND]H, CO2,Et, or 2 × CO2 Me) can be transformed into olefins with aliphatic and aromatic aldehydes (R1[DOUBLE BOND]iPr, trans-PhCH[DOUBLE BOND]CH, Ph, 4-NO2C6H4, etc.). Readily accessible starting materials, easy handling, mild reaction conditions, and good yields characterize the new synthesis method. (R′[DOUBLE BOND]Ph, 3-C6H4SO3Na, nBu.)

    5. Salt-free Synthesis of Azo and Hydrazone Dyes Under CO2 Pressure (pages 1643–1644)

      Dr. Roderich Raue, Dr. Alfred Brack and Dr. Karl H. Lange

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116431

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      A large ecological advantage is evident in the synthesis of azo dyes according to Equation (a). The nitrous acid is released from its salts or esters by CO2 pressure, which reduces the quantity of salts produced as side products considerably. Heterocyclic amines can also be diazotized successfully in this one-step reaction and coupled quantitatively with tertiary aromatic amines (e.g. R1 = 3,4-diazapyrrol-2-yl. R2 = ethyl, R3 = benzyl).

    6. Synthesis and Structure of Ethynyl Isocyanide (pages 1644–1646)

      Dipl.-Chem. Michael Krüger, Prof. Dr. Helmut Dreizler, Dipl.-Chem. Dagmar Preugschat and Priv.-Doz. Dr. Dieter Lentz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116441

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      Unexpectedly stable is ethynyl isocyanide 1, the parent compound of the hither-to unknown alkynyl isocyanides. It is storable at −196°C for several weeks and at room temperature for several days in the gas phase. Compound 1 is obtained by flash vacuum pyrolysis of the chromium complex 2. The microwave data of 1 described in this communication enabled it to be detected (after submission of this paper) in interstellar space by radioastronomy where other nitrogen-containing isomeric pairs consisting of uncharged closed-shell molecules, as well as its isomer HC[TRIPLE BOND]C[BOND]N, abound.

    7. A New Chromogenic β-Galactosidase Substrate: 7-β-D-Galactopyranosyloxy-9,9-dimethyl-9H-acridin-2-one (pages 1646–1648)

      Dr. Paul F. Corey, Dr. Robert W. Trimmer and William G. Biddlecom

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116461

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      Hydrolysis of the title compound at pH 8 causes a color shift of 196 nm (438 [RIGHTWARDS ARROW] 634 nm). The total synthesis, kinetic parameters, and application in enzyme immunoassays are described.

    8. The Reaction of PtCl2 with an N,S,O-Coordinated Calcium Complex: Synthesis and Structure of a Complexed CaPt Anion (pages 1648–1650)

      Matthew G. Davidson, Dr. Paul R. Raithby, Dr. Ronald Snaith, Dr. Dietmar Stalke and Dr. Dominic S. Wright

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116481

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      A Ca2 complex cation combines with the Ca-Pt complex anion (shown right) to form the salt 1. It is obtained from a reaction of solid PtCl2 with [Ox2Ca(HMPA)2] in toluene under reflux. The complex anion can be considered a model for heteronuclear catalysts and for adducts of Pt2+ with DNA bases.

    9. Analysis of Polymer Latices by Small-Angle X-Ray Scattering (pages 1650–1652)

      Dipl.-Chem. Ralf Grunder, Dipl.-Chem. Young Sam Kim, Prof. Dr. Matthias Ballauff, Dr. Dietmar Kranz and Dr. Hans-Georg Müller

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116501

      Analysis—requiring no pretreatment—of the core-shell morphology of polymer latices is achieved by X-ray small-angle scattering in combination with ultra-centrifuge sedimentation. The latter technique is required for the determination of the particle size distribution. For larger scattering angles (g > 0.1 nm−1), the measured and calculated scattering intensities agree quantitatively; the differences for the smallest g values may be attributed to interparticle interferences and give information on the interaction of the particles.

    10. Derivatives of 1,1″-Biferrocene with Sulfur and Selenium Bridges (pages 1652–1654)

      Prof. Dr. Max Herberhold, Dipl.-Chem. Hans-Dieter Brendel and Prof. Dr. Ulf Thewalt

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116521

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      Tetralithiated species are formed as intermediates during the preparation of the tetra-substituted derivatives of 1,1″-biferrocene, which have now been prepared for the first time. Such intermediates react not only with Me3SiCl and MeSSMe, but also with sulfur and selenium, yielding as major products the tetrachalcogenides 1. The chalcogenide atoms hold the ferrocene units together by S2 or Se2 bridges.

    11. New Routes to the Synthesis of Polymers Containing Nitrile Groups (pages 1654–1656)

      Dr. Holger Brackemann, Prof. Dr. Michael Buback, Dipl.-Chem. Frank Rindfleisch and Dipl.-Chem. Stefan Rohde

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116541

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      Polymers consisting of pure C[BOND]C chains and nitrile substituents promise to be competitive elastomers. This type of polymer can now be prepared by two routes : firstly by direct excimer laser-induced free-radical copolymerization of ethene and acrylonitrile and secondly by a polymer modification reaction of ethene-acrylate copolymer in dense fluid ammonia [Eq. (a)].

    12. The X-ray Crystal Structure Analysis of a Fragmentable N-Acylpyridinium Ion (pages 1656–1658)

      Dipl.-Chem. Christian Lohse, Dipl.-Chem. Sandro Hollenstein and Priv.-Doz. Dr. Thomas Laube

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116561

      Thumbnail image of graphical abstract

      Conjugation in the π and σ systems stabilizes the positive charge in the N-tert- butoxycarbonyl-4-dimethylaminopyridinium ion (1). This follows from the distances and angles in the salt 1-BF4 determined by X-ray crystallography. The structural features are also in accord with the easy transfer of Boc by 1 and with the decomposition of Boc into CO2 and isobutene.

    13. Double Insertion of Alkynes into Chromium-Carbon Bonds of β-Donor-Substituted Vinylcarbene Complexes of Chromium—A Simple Route to Cyclopenta[b]pyrans (pages 1658–1660)

      Dipl.-Chem. Frank Stein, Dipl.-Chem. Michael Duetsch, Dr. Rolf Lackmann, Dr. Mathias Noltemeyer and Prof. Dr. Armin de Meijere

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116581

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      Only products with severely restricted substitution patterns could be produced, and in low yields, by the multistep syntheses previously known for the pseudoazulenes. In contrast, the easily obtained vinylcarbenechromium complex 1 described here offers a simple high-yield access to the cyclopenta[b]pyranes 2 when a quaternary group occupies the β-position. The X-ray structural analysis shows that the rings of the heterobicycle 2 deviate from planarity by a mere 3.7o.

    14. Surface Organometallic Chemistry on Oxides: Selective Catalytic Low-Temperature Hydrogenolysis of Alkanes by a Highly Electrophilic Zirconium Hydride Complex Supported on Silica (pages 1660–1661)

      Christine Lecuyer, Dr. Francoise Quignard, Dr. Agnès Choplin, Prof. Danielle Olivier and Dr. Jean-Marie Basset

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116601

      At 50°C already the hydrogenolysis of neopentane, isobutane, and propane is catalyzed by the silica-supported zirconium hydride [( ⦠ SiO)3Zr[BOND]H]. The reaction selectively produces methane together with isobutane, propane, and ethane, respectively. The activity is attributable to the high electrophilicity of the 8-electron do complex and is not observed for nonsupported, discrete zirconium hydrides. Moreover, the attachment to the support prevents a bimolecular deactivation.

    15. New Chiral Polyamide Stationary Phases for Chromatographic Enantiomer Separation (pages 1662–1664)

      Prof. Dr. Dieter Arlt, Dr. Bruno Bömer, Dr. Rolf Grosser and Dr. Walter Lange

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116621

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      The diastereomeric polyamides 1 and 2 furnish stationary phases for enantiomeric separations with high enantiostereoselectivity. These methacryloylamides can be obtained in good yield in kg quantities and can be polymerized on stationary phases as well as transformed into crosslinked bead polymers for use in preparative separations.

    16. Diastereo- and Enantioselective Michael Addition Initiated Cyclizations to trans-Substituted Cyclopentanecarboxylates (pages 1664–1666)

      Prof. Dr. Dieter Enders, Dipl.-Chem. Hermann J. Scherer and Dr. Gerhard Raabe

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116641

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      Diastereomeric and enantiomeric excesses of greater than 95 % were achieved in the preparation of the cyclopentanecarboxylate 3 by asymmetric MIRC (Michael initiated ring closure) reactions of the hydrazones 1 with the unsaturated brominated ester 2. The de and ee values were determined by gas chromatography and in NMR experiments. R[DOUBLE BOND]Me, nBu, iBu, Ph, p-BrC6H4.

    17. Nickel(0)-Carbene Complexes (pages 1666–1668)

      Barbara Gabor, Prof. Dr. Carl Krüger, Dr. Bernd Marczinke, Dr. Richard Mynott and Prof. Dr. Günther Wilke

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116661

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      A tetracarbenenickel(0) complex could not be synthesized, but a study on this theme provided other interesting results. The 16e nickel(0)–carbene complexes 2 and 3 arise on protonation or methylation, respectively, of complexes 1 formed from tris(ethene)nickel(0) and the addition product of phenyllithium and tert-butyl isocyanide. (PMDTA = pentamethyldiethylenetriamine.).

    18. Tetraalkoxytitanium-Carbene Complexes with Double Intramolecular Et2Al Bridging (pages 1668–1670)

      Prof. Dr. Carl Krüger, Dr. Richard Mynott, Carsten Siedenbiedel, Ludwig Stehling and Prof. Dr. Günther Wilke

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116681

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      The first titanium[BOND]carbene complex (1) not derived from titanocene is formed on reaction of a titanium(IV) diolate with AlEt3. The structure of this heterobimetallic carbene complex is strongly reminiscent of that of the Tebbe reagents. 3,3-Dimethylcyclopropene reacts with 1 by ring opening and yields analogous carbene complexes.

    19. Novel Tetranuclear Iron[BOND]Hexapentaene Complexes: The First Examples of Poly-π-Allyl Complexes (pages 1670–1672)

      Prof. Dr. Masahiko Iyoda, Dr. Yoshiyuki Kuwatani, Prof. Dr. Masaji Oda, Prof. Dr. Kazuyuki Tatsumi and Prof. Dr. Akira Nakamura

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116701

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      Four Fe(CO)3 groups are bound to a C6 chain by π-allyl coordination in the species 2 and 3. They are obtained in low yield by reaction of hexapentaene (1, R[DOUBLE BOND]H) and 2,7-dimethylocta-2,3,4,5,6-pentaene (1, R[DOUBLE BOND]CH3) with [Fe3(CO)12]. The structural analysis agrees with the theoretical calculation of the bonding: the coordination weakens and thus lengthens the central C[BOND]C bond the most.

    20. (NBu4)[Mn4O2(H2O)(O2CPh)9], a Butterfly Complex with Bound H2O, and Its Use to Prepare Octanuclear and Undecanuclear Metal Complexes (pages 1672–1674)

      Sheyi Wang, Dr. John C. Huffman, Dr. Kirsten Folting, Dr. William E. Streib, Dr. Emil B. Lobkovsky and Prof. Dr. George Christou

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116721

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      The modeling of systems for the water oxidation center (WOC) in photosynthesis took a step forward with the preparation of the first complex that contains a bound water molecule (see structure to the right). The hydrogen bond between the aqua ligand (o 18) and a carboxylate group might provide insight into how the substrate is bound in the WOC and how deprotonation in the H2O oxidation is activated.

    21. Template-Controlled Formation of Cluster Shells or a Type of Molecular Recognition: Synthesis of [HV22O54(ClO4)]6− and [H2V18O44(N3)]5− (pages 1674–1677)

      Prof. Dr. Achim Müller, Erich Krickemeyer, Dipl.-Chem. Michael Penk, Dipl.-Chem. Ralf Rohlfing, Anja Armatage and Dr. Hartmut Bögge

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116741

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      Anions as templates for “host” anions determine the shape of molecular cavities (cluster shells) which form from differently coupled tetragonal-pyramidal OVO4 building blocks. For example, in the case of the cluster anions [HV22O54(ClO4)]6− and [H2V18O44(N3)]5− (depicted on the right) the construction of the cluster shells are achieved by “recognition” of the (O[BOND]O)2− or N(N)N units.

    22. Synthesis and Structure of the First Tellurium(III) Radical Cation (pages 1677–1678)

      Dr. Már Björgvinsson, Dipl.-Chem. Thorsten Heinze, Prof. Dr. Herbert W. Roesky, Dr. Frank Pauer, Dr. Dietmar Stalke and Prof. George M. Sheldrick

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116771

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      The first TeIII radical cation 1 occurs as monomer in its AsF6 salt. This was proved for 1-AsF6, obtained unexpectedly from the reaction of Te(N(SiMe3)2)2 with AgAsF6 in the form of black crystals. The blue metastable solutions in CH2Cl2 and CHCl3 display only one broad ESR peak, showing that the unpaired electron occupies a p orbital on telluriurn.

    23. Tetrakis(dimethylamino)ethene: An Extremely Electron-Rich Molecule with Unusual Structure both in the Crystal and in the Gas Phase (pages 1678–1681)

      Prof. Dr. Hans Bock, Dr. Horst Borrmann, Dr. Zdenek Havlas, Prof. Dr. Heinz Oberhammer, Dipl.-Chem. Klaus Ruppert and Prof. Dr. Arndt Simon

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116781

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      An unusual and chiral molecular framework characterizes the crystal structure of the air-sensitive title coumpound 1, which solidifies at 273 K. The molecular fragments on either side of the stretched C[DOUBLE BOND]C bond (138 pm) are twisted by 28° relative to each other (picture bottom right). Even in the gas phase 1 shows an unusual molecular structure, dictated by steric congestion. The four nitrogen electron pairs of the substantially flattened dimethylamino substituents are bent out of the optima1 orientation for π interaction (the torsion angle ω(CC-NC2) is 55o.

    24. Synthesis of an Elicitor-Active Heptaglucan Saccharide for Investigation of Defense Mechanisms of Plants (pages 1681–1682)

      Dr. Jens Peter Lorentzen, Dr. Barbara Helpap and Dr. Oswald Lockhoff

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116811

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      Few steps and a very good yield are characteristics of the block synthesis of a heptasaccharide that is the smallest strongly elicitor-active unit binding to a receptor in the host–parasite system, soybean/Phytophthora megasperma. The intermediates central to the block synthesis are the thiotrisaccharide donor 1 and the glycosyl acceptor 2 (Ac[DOUBLE BOND]CH3CO, Bz[DOUBLE BOND]C6H5CO, Bzl[DOUBLE BOND]C6H5CH2).

    25. Synthesis of Muropeptide Conjugates of 2,3-Dideoxy-β-D-manno-2-octulosonic Acid (pages 1682–1684)

      Dr. Hans-Georg Lerchen and Dr. Hein-Peter Kroll

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116821

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      Although an inhibitor of the bacterial lipopolysaccharide biosynthesis, the title compound 2-deoxy-β-KDO (1) cannot pass through the bacterial membrane. The coupling of the carboxy function with peptidic carriers creates conjugates (prodrugs) like 2, which can be actively transported into the cell. Their stability in vivo can be modulated by modifying the potential cleavage sites.

    26. The Reaction-Accelerating Neighboring-Group Effects in the Reaction of Vinyl Bromides with Alkyl-Transition Metal Reagents (pages 1684–1685)

      Prof. Dr. Thomas Kauffmann and Dr. Dirk Stach

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116841

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      The neighboring-group effect is not caused by the electron-donor center itself, but probably by the metal atom bound to it in an intermediate such as 1. The result of the effect is that α or β donor substituents (OH, OMe, NC) in vinyl bromides (for example 2) strongly accelerate the alkylating substitution reaction with alkyl transition-metal reagents like Me4MnLi2. The more pronounced effect of α substituents is also in agreement with the proposed intermediate 1 (n = 0), because five-membered rings are known to form more readily than six-membered rings. [M] = Fe or Mn complex fragments.

    27. Enantioselective and Diastereoselective Total Synthesis of the Antimycotically Active Natural Product Chlorotetaine: Revision of the Relative Configuration (pages 1685–1687)

      Dr. Hanno Wild and Dr. Liborius Born

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116851

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      With the bislactim ether method, followed by deprotonation with a chiral base the enantio- and diastereoselective construction of the unusual C-terminal amino acid of the dipeptide, chlorotetain (1) isolated from Bacillus subtilis, was achieved. Chlorotetain has an (S) configuration at the cyclohexenyl residue of the side chain, which contradicts the assignment reported in the literature.

    28. Tandem Silyl Migrations Leading to α,β-Bis-silylated Enals and Enones (pages 1687–1688)

      Dr. Bernd Mergardt, Dipl.-Chem. Klaus Weber, Dr. Gunadi Adiwidjaja and Prof. Dr. Ernst Schaumann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116871

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      A reaction sequence starting with a silyl-Wittig rearrangement and followed by another 1,2-silyl migration yields the α,β-unsaturated ketones or aldehydes 3 from the alkynyl ethers 1. The β-alkynols 2 are the intermediates, which in spite of many functional groups are storable at 0°C. Compounds 2 and 3 are useful synthetic building blocks. (R1 = Me, tBu, CMe2iPr; R[DOUBLE BOND]H, Me.)

    29. Selective p-Chlorination of Biphenyl in L Zeolites (pages 1689–1690)

      Dr. Artur Botta, Dr. Hans-Josef Buysch and Dr. Lothar Puppe

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116891

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      An industrial attractive access to 4,4′-dichlorobiphenyl (1) is provided by the chlorination of biphenyl with Cl2, catalyzed by zeolite L, which is modified by a variety of exchangable cations. The highest selectivity (96.7 %) was achieved in dichloromethane at 40°C with Li-zeolite L and a 10% excess of Cl2. Compound 1 is an interesting precursor for high-performance polymers that require production with as little contamination from other polychlorinated biphenyls as possible.

    30. Stereoselective Synthesis of Cyclic Dipeptide Hydroxyalkyl Isosteres via Metalated N,N-Dialkylcarbamate 2-Alkenyl Esters (pages 1690–1693)

      Dr. Rudolf Hanko, Dr. Klaus Rabe, Robert Dally and Prof. Dr. Dieter Hoppe

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116901

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      Potential protease inhibitors are formed stereoselectively by a reaction sequence that begins with the conversion of N-protected α-amino aldehydes with the homoenolate reagent 1. The lactones 2 thus formed may be coupled with α-amino acid amides by a new variation of the Weinreb method in which dialkylaluminum amides are used as ring-opening agents. In this way four diastereomers of the compounds 3 belonging to the Ψ-Phe[CHOHCH] progroup are formed. R[DOUBLE BOND]CF3CO, Cb[DOUBLE BOND]C(C[DOUBLE BOND]O)NiPr2, Bn[DOUBLE BOND]PhCH2.

    31. Isophlorins: Molecules at the Crossroads of Porphyrin and Annulene Chemistry (pages 1693–1697)

      Michael Pohl, Dr. Hans Schmickler, Dr. Johann Lex and Prof. Dr. Emanuel Vogel

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116931

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      The isophlorins already discussed by Woodward in connection with chlorophyll synthesis are Janus-faced—on one hand porphyrins (N, N′-dihydroporphyrins) and on the other true annulenes ([20] annulenes not conforming to the Hückel rule)—and as such are structurally particularly interesting. Whereas isophlorins not substituted at NH have evaded discovery and synthesis, the N, N′, N″, N″′-tetramethyloctaethylisophlorin (1, R[DOUBLE BOND]CH3) has been prepared by two-electron reduction of the known N, N′, N″, N″′-tetramethyloctaethylporphyrin dication.

    32. Stereoselective Synthesis of Annelated Piperidines by Photochemical Cycloaddition and Iminium Ion[BOND]Allylsilane Cyclization (pages 1697–1699)

      Prof. Dr. Lutz F. Tietze and Josef R. Wünsch

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116971

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      Only one of eight possible diastereomers is produced on treatment of enamine carbaldehydes 1 (R[DOUBLE BOND]H, CH3, p-MeOC6H5CH2) with alkenes 2(n = 1, 2) that contain electron acceptor and allylsilane groups. A photochemical cycloaddition yields the 2-hydroxytetrahydropyridine 3, which cyclizes on addition of acids to the azabicycles 4. In the iminium ion intermediate stage, the allylsilane group attacks C2 anti to the H atom bound to C3.

    33. Three- and Fourfold Bridgehead-Substituted Tribenzotriquinacenes (pages 1699–1702)

      Dr. Andreas Schuster and Dr. Dietmar Kuck

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199116991

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      The pyramidalized olefin 1 is the key intermediate for the synthesis of bridgehead-substituted tribenzotriquinacenes. Intermediate 1 allows access to up to fourfold substituted tribenzoquinacenes as readily as to the unsubstituted cyclopropatribenzoquinacene.

    34. 1,3-Dipolar Cycloaddition as the Key Reaction in the Synthesis of Potent Renin Inhibitors (pages 1702–1704)

      Dr. Günter Benz, Dr. Rolf Henning and Dr. Johannes-Peter Stasch

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117021

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      Substitued allylamines like 1 react with nitrones 2 by 1,3-dipolar cycloaddition to form isoxazolidines 3, which are separable by chromatography. Hydrogenolytic opening of the isoxazolidines yields 1,3-amino alcohols, which when built into the angiotensinogen sequence, lead to renin inhibitors of type 4.

    35. A New Approach to 2-Equivalent Couplers for Color Photography (pages 1704–1706)

      Dr. Peter Bergthaller

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117041

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      By introducing a selenium(IV) group into the coupling position of anilinopyrazolones and naphthols, for example with SeO2, it is possible for the first time to convert the corresponding 4-equivalent couplers directly into 2-equivalent couplers with a triazole leaving group. Thus treatment of 1 with SeO2 yields 2, which reacts with a benzotriazole by selenium cleavage to afford 3.

    36. The Synthesis of the First Decametal Nitrido Cluster; X-Ray Structure Analysis and 14N NMR Studies of [(Ph3P)2N][Ru10N(CO)24] (pages 1706–1707)

      Dr. Philip J. Bailey, Dr. Gráinne C. Conole, Prof. Brain F. G. Johnson, Jack Lewis, Prof. Mary McPartlin, Dr. Adrian Moule and Dr. Della A. Wilkinson

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117061

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      A fourfold capped octahedral metal framework known previously only in carbido and hydrido clusters constitutes the structure of the monoanion [Ru10N(CO)24] (picture right). This cluster may be prepared in several ways; if forms without impurities that are difficult to remove on reaction of the octahedral cluster [Ru6N(CO)16] with [Ru3(CO)12]. equation image

    37. Dilithiation of a Primary Amine: Synthesis and Structure of [(α-Naphthyl-NLi2)10(Et2O)6] · Et2O, a Paramagnetic Li20 Aggregate (pages 1707–1709)

      Dr. David R. Armstrong, Dr. Donald Barr, Dr. William Clegg, Dr. Simon R. Drake, Dr. Richard J. Singer, Dr. Ronald Snaith, Dr. Dietmar Stalke and Dr. Dominic S. Wright

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117071

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      Ab initio calculations predict the stablest dilithiated α-naphthylamine to be the isomer depeicted here. The C8 and N atoms are deprotonated and the two Li atoms occupy bridging positions between them. The reaction of α-naphthylamine with nBuLi in ether at −40°C affords the title complex, whose structure is characterized by a central N10Li14 cluster formed by two face-sharing rhombic dodecahedrons. Amazingly the compound is paramagnetic in solution and in the solid.

    38. 4-Acyl-2,3,4,5-tetrahydro-2-methyl-2,5-methanobenz-1,4-oxazepine, Derivatives of a New Heterocycle (pages 1709–1711)

      Dr. Hans-Joachim Kabbe, Dr. Helmut Heitzer and Dr. Liborius Born

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117091

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      Two rotamers that are stable in the solid state can be isolated separately for the heterocycle 1. Variation of the crystallization method provides the two modifications that differ in the orientation of the carbonyl group on nitrogen: the CO group points either towards the benzene ring (depicted right) or away from it.

    39. Antibody Catalysis of Glycosidic Bond Hydrolysis (pages 1711–1713)

      Dr. Jean-Louis Reymond, Prof. Kim D. Janda and Prof. Richard A. Lerner

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117111

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      For the preparation of abzymes with glycolytic activity, the generation of an antibody that catalyzes the hydrolysis of acetal 1 represents a first step. The antibody (or abzyme) is obtained from immunization with piperidinium hapten 2. A key factor in promoting catalysis is probably the proper placement of the leaving group in 1 as axial substituent.

  3. Corrigenda

    1. Top of page
    2. Reviews
    3. Communications
    4. Corrigenda
    5. Author Index
    6. Subject Index
    1. You have free access to this content
      Corrigendum (page 1713)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117131

  4. Author Index

    1. Top of page
    2. Reviews
    3. Communications
    4. Corrigenda
    5. Author Index
    6. Subject Index
    1. Author Index [Angew. Chem. Int. Ed. Engl. 30 (1991)] (pages 1721–1727)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117211

  5. Subject Index

    1. Top of page
    2. Reviews
    3. Communications
    4. Corrigenda
    5. Author Index
    6. Subject Index
    1. Subject Index (pages 1729–1749)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199117291