Angewandte Chemie International Edition in English

Cover image for Vol. 34 Issue 7

April 13, 1995

Volume 34, Issue 7

Pages 705–829

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 7/1995)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507031

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      The cover picture shows the structure of hexakis(trimethylsilylethynyl)[3]radialene, a carbon-rich compound with unusual electronic properties. This trimethylsilyl derivative of a C18H6 hydrocarbon, which could serve as a monomer for a two-dimensional carbon network, can be prepared from readily available compounds in only a few steps. The [3]radialene forms deep red crystals, and unexpectedly its absorption is strongly red-shifted. Solutions of the radialene in dichloromethane are purple-red; electrochemical reduction proceeds through a rainbow of colors from purple-red over violet to light green. F. Diederich et al. report more on this interesting compound on pages 805–809.

      This issue of Angewandte Chemie serves as a launching pad for the first issue of Chemistry—A European Journal, which is bound at the back. A separate Table of Contents at the beginning of the “Chemistry” section gives more information about the contributions in the inaugural issue.

    2. Graphical Abstract (Angew. Chem. Int. Ed. Engl. 7/1995) (pages 705–710)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507051

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. Calixarenes, Macrocycles with (Almost) Unlimited Possibilities (pages 713–745)

      Dr. Volker Böhmer

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507131

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      Cyclic oligomers in which phenol or resorcinol units are linked by methylene or alkylidene bridges are called calixarenes and resorcarenes, respectively. They can be readily prepared in large quantities and are ideal starting materials for the synthesis of a large number of host molecules, in which these basic structures are modified or are combined to give larger units as in 1. Potential applications of calixarenes include their use as highly specific ligands for analytical chemistry, the decontamination of waste water, the construction of artificial enzymes, and the preparation of new materials.

    2. Carbon—Hydrogen Bonds of DNA Sugar Units as Targets for Chemical Nucleases and Drugs (pages 746–769)

      Dr. Geneviève Pratviel, Prof. Dr. Jean Bernadou and Dr. Bernard Meunier

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507461

      A hydrogen abstraction as first step is the common feature of the nonenzymatic DNA cleavages presented here. The cleavage reagents are redox-active transition metal complexes endowed with affinity for DNA and cytotoxic natural substances like enediynes and bleomycins. They all attack the deoxyribose sugar unit of DNA, and any one of the five hydrogen atoms could be abstracted. After a survey of the modes of activation and binding to DNA, current ideas on the molecular mechanisms of the DNA degradation by these substances are discussed.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. The Dinuclear CuA Center in Cytochrome c Oxidase and N2O Reductase—A Metal–Metal Bond in Biology? (pages 771–773)

      Prof. Dr. Helmut Bertagnolli and Prof. Dr. Wolfgang Kaim

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507711

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      A Cu[BOND]Cu bond in the mixed-valent CuA center of cytochrome c oxidase of Bacillus subtilis was postulated last year, though with necessary caveats, on the basis of EXAFS measurements. The deduced arrangement (bottom left) contradicts another structural proposal (bottom right) from the same year. A critical appraisal of all evidence available at present still suggests a negative answer to the question posed in the title.

    2. Total Syntheses of Zaragozic Acid (pages 773–778)

      Dr. Ulrich Koert

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507731

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      Three total syntheses of zaragozic acids, a new group of natural products with blood cholesterol lowering properties, were successfully developed within a short time and published almost simultaneously. Convergence, skilled manipulation of protecting groups, and highly stereoselective reactions are the appealing features of these first syntheses of zaragozic acid A (Nicolaou) and zaragozic acid C (1) (Carreira and Evans).

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. Modeling the Remote-Controlled Organization of Particles in a Nanodimensional Cavity: Synthesis and Properties of (Et3NH)3(tBuNH3)2-Na2[(H2O)2,Nmath image ⊂ V14O22(OH)4(PhPO3)8]· 6H2O·2DMF (pages 779–781)

      Prof. Dr. Achim Müller, Dipl.-Chem. Kai Hovemeier, Erich Krickemeyer and Dr. Hartmut Bögge

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507791

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      The arrangement of charged and uncharged guests (Nmath image and two H2O molecules; see structure on the right) and their interaction in the cavity of the anion of the title compound 1 can be controlled by deliberately exchanging particles in the truncated cone outside the host (not shown), which resembles an ion channel. Since 1 can incorporate a diversity of guests, continuing studies promise exciting insights into these interactions.

    2. The Reactivity of 1,3-Butadiyne Moieties in the “Exploding” [n]Rotanes—A Crown of Thiophenes (pages 781–783)

      Dr. Sergei Kozhushkov, Dipl.-Chem. Thomas Haumann, Prof. Dr. Roland Boese, Dr. Burkhardt Knieriem, Dipl.-Chem. Stefan Scheib, Prof. Dr. Peter Bäuerle and Prof. Dr. Armin de Meijere

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507811

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      Crowns of thiophenes of type 2 with five, six, and eight heterocycles were obtained in moderate to good yields in the reaction of the appropriate [n]rotanes of type 1 and Na2S. In the crystal 2 adopts a chairlike conformation with three thiophene S atoms above and three below the equatorial plane of the macrocycle.

    3. A Simple, Chirogenic, Enantioselective Synthesis of Chlorins and Isobacteriochlorins (pages 784–787)

      Dr. Dirk Kusch, Dr. Elke Töllner, Anngret Lincke and Prof. Dr. Franz-Peter Montforts

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507841

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      Geminal dialkylated hydroporphyrins are important as intermediates of the vitamin B12 biosynthesis or as cofactors of reducing enzymes in bacteria and plants. They can be synthesized enantioselectively by asymmetric reduction of acylporphyrins and amide acetal Claisen rearrangement with transfer of chirality, and can form complexes like 1 with metals.

    4. Highly Stereoselective Allylation of Benzaldehyde: Generation of a Stereochemically Defined Allylzinc Species from a π-Allylpalladium Intermediate and Diethylzinc (pages 787–789)

      Prof. Yoshinao Tamaru, Akihiro Tanaka, Kengo Yasui, Sachio Goto and Shuji Tanaka

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507871

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      Umpolung of the π-allyl group in π-allylpalladium intermediates is possible by alkylallyl exchange with diethylzinc. The resulting nucleophilic allylzinc species can attack benzaldehyde. Thus reaction of the cyclohexenyl ester trans-1 yields cis-syn-2 selectively. This stereoselectivity can be explained with transition state structure I. 1,3-Disubstituted allyl compounds undergo analogous reactions with regio- and stereoselectivity. L[DOUBLE BOND]PPh3.

    5. Novel “π-Boat” Cage Compounds as Potential Cryptands (pages 789–791)

      Prof. Dr. Rolf Gleiter, Kirstin Hövermann, Dipl.-Chem. Joachim Ritter and Dr. Bernhard Nuber

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507891

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      Not only aesthetic, but also structurally interesting are the novel bridged π systems like 1 with “π boat” units. They can be synthesized by cyclization of 1,6-diazacyclodeca-3,8-diyne with dihalides. Whether the trimer 1 or a monomer or dimer forms depends on the geometrical properties of the bridge monomers employed (in 1para-substituted benzene).

    6. Coordination of CO to the Alkaline Earth Metallocene [(Me5C5)2Ca] (pages 791–793)

      Dipl.-Chem. Peter Selg, Prof. Dr. Hans H. Brintzinger, Prof. Dr. Richard A. Andersen and Dr. István T. Horváth

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507911

      The exothermic formation of a Ca–CO complex [Eq.(a), ΔHo = −25 kJ mol−1] confirms that CO can bind to a metal center without π back donation from filled d orbitals. In its spectroscopic properties, the calcocene–carbonyl complex resembles “nonclassical” noble metal carbonyl complexes. Cp* = η5-C5Me5.

      • equation image
    7. Benzopyranoisoxazolidines as Chiral Auxiliaries for Asymmetric Synthesis (pages 793–795)

      Dr. Atsushi Abiko, Dr. Osamu Moriya, Dr. Sandra A. Filla and Prof. Satoru Masamune

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507931

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      The asymmetric alkylation of N-propionylisoxazolidines (2a and 2b), which are prepared by treatment of 1a and 1b with propionyl chloride and triethylamine, proceeds with high diastereoselectivity, even with β-branched alkyl triflates. The alkylated products 3 can be converted into the alcohols 4, aldehydes 5, and ketones 6 in high yields in one step with recovery of the auxiliary 1.

    8. Formation of a Hexagonal Columnar Mesophase by N-Acylated Poly(ethylenimine) (pages 795–798)

      Dr. Hartmut Fischer, Surya S. Ghosh, Prof. Paul A. Heiney, Nicholas C. Maliszewskyj, Thomas Plesnivy, Prof. Helmut Ringsdorf and Markus Seitz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507951

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      Both discotic molecules and certain linear polymers form columnar hexagonal mesophases. Whereas the dislike structure of the macrocycle 1 is dictated by the molecular shape, in polymer 2 it is presumably enforced by a helical folding of the polymer's main chain induced by the side chains (bottom right).

    9. C2-Symmetric Cationic Copper(II) Complexes as Chiral Lewis Acids: Counterion Effects in the Enantioselective Diels–Alder Reaction (pages 798–800)

      Prof. David A. Evans, Jerry A. Murry, Peter von Matt, Roger D. Norcross and Scott J. Miller

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199507981

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      Alone a tailor-made chiral cationic Lewis acid is not sufficient to achieve high enantiomic excesses in Diels–Alder reactions; the counterion can dramatically affect the efficiency of the chiral catalyst. Thus, for example, the enantioselectivities reached in these reactions in the presence of the copper complex 1 with X = SbF6 as counterion are in some cases substantially greater than those with X = OSO2CF3.

    10. Aminocyclopentadienes, Aminoferrocenes, and Aminocobaltocenes (pages 800–803)

      Dr. Herbert Plenio and Dipl.-Chem. Dirk Burth

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508001

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      Good access to the title compounds is provided by the reaction shown below. Compound 1 reacts readily with secondary amines to give N,N-dialkylaminocyclopentadienes 2, whose Li salts can be treated, for example, with FeCl2 to give the ferrocene derivatives 3.

    11. A Novel Allylic Anchor for Solid-Phase Synthesis—Synthesis of Protected and Unprotected O-Glycosylated Mucin-Type Glycopeptides (pages 803–805)

      Dipl.-Chem. Oliver Seitz and Prof. Dr. Horst Kunz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508031

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      An efficient solid-phase synthesis of glycopeptides is achieved with the new anchor HYCRON, which combines an allylic ester with the flexible, solubilizing triethyleneglycol spacer. Acid- and base-stability of the allylic anchor enables both Fmoc and Boc strategies to be used. The partially protected glycopeptides can be cleaved from the support by Pd0 catalysis under virtually neutral conditions in high yields (about 95%) and purity (>95%). AMPS = aminomethylpolystyrene.

    12. Hexakis(trimethylsilylethynyl)[3]radialene: A Carbon-Rich Chromophore with Unusual Electronic Properties (pages 805–809)

      Tim Lange, Dr. Volker Gramlich, Dr. Walter Amrein, Prof. François Diederich, Prof. Maurice Gross, Dr. Corinne Boudon and Dr. Jean-Paul Gisselbrecht

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508051

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      Hexaethynyl[3]radialene (1 a) is isoelectronic and isosteric with the known hexacyano[3]radialene and a molecular precursor for a two-dimensional all-carbon network. The hexakis(trimethylsilyl) derivative 1 b was now prepared by addition of tetrachlorocyclopropene to deprotonated 1,5-bis(trimethylsilyl)penta-1,4-diyne, followed by oxidation, and was characterized by X-ray crystallography. In solution, 1 b shows an unexpected purple-red color and is reduced in two reversible one-electron steps to the violet radical anion 1 b and dianion 1 b2−.

    13. Bis(pentafluorophenyl)borane: Synthesis, Properties, and Hydroboration Chemistry of a Highly Electrophilic Borane Reagent (pages 809–811)

      Daniel J. Parks, Dr. Rupert E. von H. Spence and Prof. Warren E. Piers

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508091

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      A facile route provides the title compound 1 in only a few steps starting from bromopentafluorobenzene. Borane 1 is a very reactive hydroborating agent for a range of alkenes and alkynes. Reactions with unsymmetrical substrates display excellent regioselectivity, and interesting selectivities with silicon-containing substrates are rationalized by electronic effects.

    14. New Process for the Sulfonation of Phosphane Ligands for Catalysts (pages 811–813)

      Prof. Dr. Wolfgang A. Herrmann, Guido P. Albanese, Dr. Rainer B. Manetsberger, Dr. Peter Lappe and Dr. Helmut Bahrmann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508111

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      The direct sulfonation of arylphosphanes with H2SO4/SO3/boric acid offers numerous advantages, the most significant being that P oxidation is largely avoided. In addition, selective sulfonation is possible. The products, for example 1, are water-soluble and interesting with respect to two-phase catalysis. Ar = C6H4-m-SO3Na.

    15. First Determination of the Ionization Potential of Americium and Curium (pages 814–815)

      Dipl.-Chem. Rüdiger Deissenberger, Dipl.-Phys. Stefan Köhler, Dr. Friedhelm Ames, Dr. Klaus Eberhardt, Dipl.-Phys. Nicole Erdmann, Dipl.-Chem. Heike Funk, Prof. Dr. Günter Herrmann, Prof. Dr. Heinz-Jürgen Kluge, Dipl.-Phys. Martin Nunnemann, Dr. Gerd Passler, Dr. Joachim Riegel, Dr. Franz Scheerer, Dr. Norbert Trautmann and Dr. Franz-Josef Urban

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508141

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      By multistep resonance ionization with lasers, followed by mass spectrometry, the first ionization potential of neutral atoms can be measured with quantities of only about one nanogram. The ionization potentials of americium (5.9736(3) eV) and of curium (5.9914(2) eV) were thus determined for the first time. The figure on the right shows a plot of the number of ions N versus the total photon energy Etot of three laser beams, which are essential for the experiment. The arrow points to the ionization threshold.

    16. Self-Diffusion of Charged Polycyclic Systems and Their Parent Compounds: A PGSE NMR Study (pages 816–818)

      Dr. Yoram Cohen and Dr. Ari Ayalon

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508161

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      Self-diffusion coefficients of a series of polycyclic charged systems and their parent compounds were measured by using the PGSE NMR method. These data suggest that the dianions of naphthacene 2 and pyracylene 3 may exist as dimers with sandwich structure, just like the lithium salt of the tetraanion of corannulene 1.

    17. The Chemistry of Silylenoids: Preparation and Reactivity of (Alkoxysilyl)lithium Compounds (pages 818–820)

      Prof. Dr. Kohei Tamao and Atsushi Kawachi

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508181

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      The ambiphilic reactivity exhibited by the silicon compound 1 contrasts the behavior of neutral silanes and simple silyl anions. This reactivtiy is an indication of silylenoid character, which can be accounted for by the two limiting electronic structures 1 a and 1 b.

    18. 2,4,6-Tri(4-pyridyl)-1,3,5-triazine as a 3-Connecting Building Block for Infinite Nets (pages 820–822)

      Stuart R. Batten, Dr. Bernard F. Hoskins and Dr. Richard Robson

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508201

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      A new three-dimensional coordination network with cubic symmetry is displayed by the structure of 1 (shown on the right). Compound 1 is obtained from tri(4-pyridyl)triazine ligands (tpt) and Hg2+ ions, and has a system of interconnected spacious cavities which are occupied by large numbers of solvent molecules and counterions. The coordination sphere of the Hg center is formed by six pyridine substituents, which is very rare for complexes.

      • equation image
    19. Reaction of a Vanadium(III) Amide with H2: Isolation and Characterization of a Polynuclear Mixed-Valence Polyhydrido–Nitrido Complex (pages 822–824)

      Pietro Berno and Prof. Dr. Sandro Gambarotta

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508221

      Complex 2 is formed by two discrete ions which originate during hydrogenolysis of 1 according to Equation (a). The cation is dinuclear with three bridging hydrido ligands. The mixed-valent anion of 2 is also dinuclear and contains two bridging nitrido moieties, which cannot be the product of the hydrogenolysis of N[BOND]Si bonds since silanes are not formed in the reaction.

      • equation image
    20. Synthesis and Structure of the First Transition Metal Borylene Complexes (pages 825–826)

      Dr. Holger Braunschweig and Trixie Wagner

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508251

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      The stable borylene-bridged Mn2 complexes 1 and 2 are formed in the reaction of K[(η5-C5H4R)-Mn(SiMePh2)(CO)2] with the diboranes(4) B2X2Cl2. The mechanism of formation still remains to be clarified. The molecular structure of 1 (R = H) shows similarities with dimetallacyclopropane derivatives.

  4. Corrigenda

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. You have free access to this content
      Corrigenda (page 826)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508261

  5. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Corrigenda
    6. Book Reviews
    1. New Books (Angew. Chem. Int. Ed. Engl. 7/1995) (page 829)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199508291

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