Angewandte Chemie International Edition in English

Cover image for Vol. 17 Issue 8

August 1978

Volume 17, Issue 8

Pages 545–620

Currently known as: Angewandte Chemie International Edition

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews
    1. A Coordination Chemist's View of Surface Science (pages 545–558)

      Prof. Dr. E. L. Muetterties

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805453

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      Chemical compounds formed at solid/gas interfaces play a key role in numerous processes. Methods of structural chemistry and surface physics can be used to study these compounds, as can the classic displacement reaction of chemistry.

    2. Spiroconjugation (pages 559–569)

      Prof. Dr. Heinz Dürr and Prof. Dr. Rolf Gleiter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805591

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      A new kind of homoconjugation, viz. spiroconjugation, occurs in spiro compounds containing mutually perpendicular π-electron systems. This intramolecular interaction can be detected, e.g. by comparison of the PE spectra of spiropolyenes such as (1) and analogous compounds such as (2).

    3. 4-Dialkylaminopyridines as Highly Active Acylation Catalysts. [New synthetic method (25)] (pages 569–583)

      Priv.-Doz. Dr. Gerhard Höfle, Prof. Dr. Wolfgang Steglich and Prof. Dr. Helmut Vorbrüggen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805691

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      Activities some ten-thousand times greater than that of pyridine are found on catalysis of acylations by pyridine derivatives DMAP and PPY. The article surveys applications, e.g. in natural products chemistry, and possible explanations of this extraordinary increase in activity.

    4. Histidine in Enzyme Active Centers (pages 583–592)

      Prof. Dr. Friedhelm Schneider

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805831

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      The role of histidine in enzymatic catalysis is due, in part, to the special features of the imidazole group: it forms H bonds, combines donor and acceptor properties, and can take part in either nucleophilic or base catalysis.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews
    1. ��f Parameters—A Measure of the Front Strain of Alkyl Groups (pages 593–594)

      Dr. Hans-Dieter Beckhaus

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805931

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      Front strain, i.e. steric repulsion of the attacking or leaving group R in a reaction, is often regarded as the principal factor determining reactivity. ��f has been defined as a measure for front strain and calculated for 48 groups R.

    2. Front Strain of π and σ Radicals (pages 594–595)

      Prof. Dr. Bernd Giese and Dr. Hans-Dieter Beckhaus

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805941

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      Whether a radical R˙ is planar (π radical) or nonplanar (σ radical) can now be decided with the aid of the newly defined ℒf parameters. Activation enthalpies ΔHmath image and ΔHmath image must also be known for competition reactions of R˙ and a series of comparable radicals.

    3. Temperature Dependence of Carbene Selectivities: A New Example of the Isoselective Relationship (pages 595–596)

      Prof. Dr. Bernd Giese and Dr. Jürgen Meister

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805951

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      The selectivity of the halocarbenes CX2 (X = F, Cl, Br) in competitive cycloaddition to (1) and (2) varies with temperature. The order of selectivity is CF2 > CCl2 > CBr2 below 330K, but CF2<CCl2<CBr2 above that temperature. All three carbenes exhibit the same selectivity in the temperature range 330±15K (isoselective temperature).

    4. Preparation and Crystal Structure of Pd2Mo25-C5H5)23-CO)22-CO)4(PEt3)2. A Planar, Triangulated, Palladium-Molybdenum-Carbonyl Cluster (pages 596–597)

      Dr. Robert Bender, Dr. Pierre Braunstein, Dr. Yves Dusausoy and Dr. Jean Protas

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805961

      A Pd2Mo2 cluster—the very first heteropolymetallic Pd cluster to be obtained—has been synthesized in 75% yield from [Mo(η5-C5H5)(CO)3] and trans-Pd(PEt3)2C12. As shown by X-ray structure analysis, the Pd atoms of this compound have the unusual coordination number 8. Moreover, only one example of a planar triangulated cluster ([Re4(CO)16]2−) was formerly known.

    5. 4-Dimethylamino-3-butyn-2-one as Activating Agent for Peptide Synthesis (pages 597–598)

      Dr. Hans-Joachim Gais

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805971

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      Very high yields, mild conditions, and no racemization are characteristic of peptide syntheses utilizing (1). R—COOH is an N-protected amino acid, R′—NH2 is an amino ester or similar species. The procedure can also be applied to R—COOH with unprotected side chain functions.

    6. Ethylenebis(diphenylphosphane)dihydrogenselenidonicke(II) (pages 598–599)

      Prof. Dr. Max Schmidt and Dipl.-Chem. Gerhard G. Hoffmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805981

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      The presence of two SeH groups on a nickel atom is the distinguishing feature of the new complex (2). The rust-red compound, whose crystals are essentially air-stable, is the first hydrogen chalcogenide of nickel(II).

    7. 2,4-Bis(dimethylcarbamoyl)-1,1-dioxo-3-phenyl-1λ6,2,4,3-thiadiazaboretidine: a BN2S Ring by “Insertion” of Sulfonyl Diisocyanate (page 599)

      Prof. Dr. Herbert W. Roesky and Dr. Sushil K. Mehrotra

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805991

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      “Insertion” of sulfonyl diisocyanate(2) into the borane (1) leads to quantitative yields of the new BN2S ring (3). The combination of electron-rich and electron-poor elements in (3) is of interest.

    8. An Unusually Versatile Solid-State Structure: Polyiodides of Type Tl6I6Mmath image(I4)2− (M = Ag, Au, Tl, Pb, Bi, Ln, Zr, Hf, Th) (pages 599–600)

      Prof. Dr. Albrecht Rabenau and Dr. Wolfgang Stoeger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197805992

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      Three channels per unit cell pass through the skeletal structure TI6I6 of the polyiodide Tl6I6Mmath image(I4)2−. The M+ ions assume a one-dimensional structure in one of the channels. The tolerence of the structure towards variations in radius, charge, and electronic configuration of M is surprising.

    9. An Organotitanium Compound with Ylide Clamps between Two Octahedrally Coordinated Metal Atoms (pages 601–602)

      Dr. Wolfgang Scharf, Dietmar Neugebauer, Dr. Ulrich Schubert and Prof. Dr. Hubert Schmidbaur

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806011

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      The novel binuclear titanium compound(1), which is without structural precedent in ylide coordination chemistry, has now been synthesized from(CH3O)3TiCl and (CH3)3P[DOUBLE BOND]CH2. Such organometallic compounds are of interest as potential homogeneous catalysts.

    10. Cycloadditions with [n]Cyclophanes (page 602)

      Dipl.-Chem. Karl-Ludwig Noble, Prof. Dr. Henning Hopf, Prof. Dr. Maitland Jones Jr. and Dr. Seetha L. Kammula

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806021

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      Diels-Alder reactions of benzene derivatives are very rare. However, sterically strained benzene rings like that in (1) can act as diene component: 1:1 addition with strong dienophiles leads to bridged barrelenes [n = 7 or 8, R[BOND]CF3 or CN (only n = 8)].

    11. Bicyclo[2.2.2]octa-5,7-die-2-one (“Barrelenone”) (pages 603–604)

      Prof. Dr. Rudolf Gompper and Dipl.-Chem. Karl-Heinz Etzbach

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806031

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      Barrelenon (1), which forms an ambifunctional anion, has been synthesized in order to subject the alkylation of this anion to a comparative study. The course of methylation of the anion of (1) and the anions of other bicyclic ketones conforms with the predictions of the principle of allopolarization.

    12. Synthesis and properties of Tris(trimethylgermyl)aluminum (page 604)

      Dr. Lutz Rösch and Dipl.-Chem. Wolfgang Erb

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806041

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      Germylaluminum compounds, of interest as higher homologs of organoaluminum compounds, were hardly known until now. The first alkylgermylaluminum derivative has been obtained as the THF adduct as shown below and exhibits astonishing thermal stability (m. p. 81°C).

    13. Evidence for a Dialkoxyalkene Radical Cation in Aqueous Solution (pages 604–605)

      Dr. Günter Behrens, Dr. Eberhard Bothe, Johann Eibenberger, Dr. Günther Koltzenburg and Prof. Dr. Dietrich Schulte-Frohlinde

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806042

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      Spontaneous elimination of Cl⊖ from the radical(1), leading to the radical cation (2), has now been demonstrated in aqueous solution. The radical character, structure, and charge of (2) were confirmed by ESR spectroscopy and pulse conductivity measurements.

    14. The Formation of Stereoisomeric (η2-Aroyl)arylbis(η5-cyclopentadienyl)zirconium(IV) Compounds (pages 605–606)

      Dr. Gerhard Erker and Dipl.-Chem. Frank Rosenfeldt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806051

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      Insertion of CO into transition metal-carbon σ-bonds plays a key role in important catalytic processes. The synthesis of (2) and its rearrangement to (3) are of interest in this context.

    15. 5-Methylenebicyclo[2.2.0]hex-2-ene, a Bicyclic Isomer of Toluene: Synthesis and Thermal Behavior (pages 606–608)

      Priv.-Doz. Dr. Dieter Hasselmann and Dipl.-Chem. Klaus Loosen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806061

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      A compound having three sp2 centers in the bicyclo[2.2.0]hexane skeleton, viz. hydrocarbon (1), has been synthesized as shown (R = CO2Me [RIGHTWARDS ARROW] CH2OH [RIGHTWARDS ARROW] CH2OTs). Thermolysis transforms (1) into 5-methylene-1,3-cyclohexadiene, a model system for polymerization studies.

    16. Intramolecular Electron Transfer of Coordinated Pyrazinecarboxylato Radicals to Cobalt(III): A Pulse Radiolytic Study (pages 608–609)

      Prof. Dr. Karl Wieghardt, Dr. Haim Cohen and Prof. Dr. Dan Meyerstein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806081

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      Short-lived radical intermediates of electron-transfer reactions have only been postulated so far. An example is species (2), assumed to occur in the reduction of the complex (1) by CrII. The first preparation and characterization of such radicals by pulse radiolysis has now been accomplished. equation image (from solvent isopropanol) served as electron-transfer agent.

    17. A General and Facile Synthesis of Aryl- and Hetero-arylacetylenes (pages 609–610)

      Prof. Dr. Curt Wentrup and Dipl.-Chem. Hans-Wilhelm Winter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806091

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      Preparative flash pyrolysis is a suitable method for the synthesis of kinetically unstable but thermodynamically stable compounds. An example is the synthesis of the acetylenes (1): R can be varied widely.

    18. Molecular Sieve Properties of Polymeric Schiff Base-Metal Complexes (pages 610–611)

      Dr. Manfred Riederer and Prof. Dr. Wolfgang Sawodny

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806101

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      Molecular sieves and solid stationary phases for gas chromatography are two surprising applications of the polymeric complex (1) and its derivatives. For example, a mixture of noble gases (He, Ne, Ar, Kr, Xe) can be completely separated (except for He/Ne) on (1).

    19. Ring Contraction by Peracid Oxidation: Preparation of cyclo-Heptasulfur Dioxide, S7O2, from S8 (pages 611–612)

      Prof. Dr. Ralf Steudel and Dipl.-Chem. Torsten Sandow

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806111

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      The first dioxide of a sulfur ring, S7O2, was unexpectedly formed from S8 on oxidation with trifluoroperacetic acid. The reaction probably proceeds via an unstable higher oxide of S8.

    20. Complete Enantiomer Separation by Chromatography on Potato Starch (pages 612–614)

      Dipl.-Chem. Heinrich Hess, Günther Burger and Prof. Dr. Hans Musso

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806121

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      The inexpensive natural product potato starch permits complete separation of enantiomers, even on a preparative scale given carefully optimized conditions. Separation of (SSS)-(−)-(1) and (RRR)-(+)-(1) serves as example.

    21. Conformationally Induced Stereospecificity in the Multiple Epoxidation of syn-9-Chloro-cis-bicyclo[6.1.0]nona-2,4,6-triene (pages 614–615)

      Prof. Dr. A. G. Anastassiou and Dr. R. L. Mahaffey

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806141

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      Progenitors of potentially aromatic mono- and polyoxaannulenyl ions, i. e. the epoxides of type (2), (3), and (4), have been synthesized. The cis isomer of (2) gives the corresponding isomers. The stereospecificity observed on oxidation is due to the rigid nonplanar conformation of the starting materials.

    22. 1,2,8,9-Tetrahydrodicyclobuta[b,g]phenathrene and 1,2,7,8-Tetrahydrodicyclobuta[b,h]phenanthrene, Potentially Carcinogenic Activated Hydrocarbons (pages 615–616)

      P. Perkins and Professor Dr. K. P. C. Vollhardt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806151

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      The strained-ring activation of polycyclic aromatic compounds such as phenanthrene may modify not only their physical and chemical properties but also their mutagenicity: Phenanthrene is inactive in the Ames test, doubly activated (1) is weakly active, and the isomer (2) inactive.

    23. IR Spectroscopic Detection of Molecular SiO2 (pages 616–617)

      Dr. Hansgeorg Schnöckel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806161

      “True” double bonds between tetravalent silicon and oxygen are present in molecular SiO2, now isolated by a novel matrix technique. This was accomplished by cocondensation of SiO (from a Knudsen cell) and O (generated by microwave excitation) in argon on a cold surface.

  3. Abstracts

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews
    1. Abstracts (page 618)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.197806181

  4. Book Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Abstracts
    5. Book Reviews

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