Angewandte Chemie International Edition in English

Cover image for Vol. 25 Issue 7

July 1986

Volume 25, Issue 7

Pages 583–660

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 7/1986)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198605831

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      The cover picture shows pieces of a puzzle of substructures of novel, cyclic conjugated [4n]-π-electron systems. The fragments are shown in the colors of the solutions of the respective “antiaromatics”. Pleiaheptalene (yellow) is the first peri-annelated [4n]-π-electron system without aromatic partial structures. 9b-Methyl-9bH-benz[cd]azulene (blue), a tricyclic [12]annulene, has an almost planar perimeter and shows pronounced paratropism. In contrast, 1,2,5,7-tetra-tert-butyl-s-indacene (red fluorescence), a planar annelated 12π-electron system, exhibits only a slight paratropic ring-current effect with extensive delocalization. More about these novel compounds is reported by K. Hafner et al. on page 630.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. A Receptor-Mediated Pathway for Cholesterol Homeostasis (Nobel Lecture) (pages 583–602)

      Prof. Michael S. Brown and Prof. Joseph L. Goldstein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198605833

      How does the healthy organism regulate cholesterol metabolism? The answer to this question was obtained, inter alia, by studies on patients with a genetic disease, familial hypercholesterolemia. Michael S. Brown and Joseph L. Goldstein recognized thereby the key role of the receptor for the cholesterol-transport protein LDL. The receptor is a well-characterized protein; studies afforded insights into endocytosis and the pathway by which the receptors enter and leave the cell. Genetic defects in the LDL receptors give rise to an accumulation of cholesterol in plasma and premature arteriosclerosis.

    2. Direct Methods and Anomalous Dispersion (Nobel Lecture) (pages 603–613)

      Prof. Dr. Herbert Hauptman

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606031

      Todays triumphant advance of X-ray structure analysis is due in large part to the development of the “direct methods” by Herbert Hauptman and Jerome Karle. Previously, it was generally assumed to be impossible to determine a structure directly from the diffraction pattern of a crystal, for a normal diffraction experiment afforded only amplitudes, but no phases of the diffraction maxima. This phase problem was overcome in a series of steps that involved recognition that the required phase information was contained in the measured intensities, the derivation of a foundation mathematics that displayed relationships between phases and magnitudes and even among phases alone and, finally, the development of practical methods for structure determination, strategies that brought together in a more or less optimal fashion the mathematical relationships with suitably adjusted and refined experimental data.

    3. Recovering Phase Information from Intensity Data (Nobel Lecture) (pages 614–629)

      Prof. Dr. Jerome Karle

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606141

      Todays triumphant advance of X-ray structure analysis is due in large part to the development of the “direct methods” by Herbert Hauptman and Jerome Karle. Previously, it was generally assumed to be impossible to determine a structure directly from the diffraction pattern of a crystal, for a normal diffraction experiment afforded only amplitudes, but no phases of the diffraction maxima. This phase problem was overcome in a series of steps that involved recognition that the required phase information was contained in the measured intensities, the derivation of a foundation mathematics that displayed relationships between phases and magnitudes and even among phases alone and, finally, the development of practical methods for structure determination, strategies that brought together in a more or less optimal fashion the mathematical relationships with suitably adjusted and refined experimental data.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Synthesis and Properties of 1,3,5,7-Tetra-tert-butyl-s-indacene (pages 630–632)

      Prof. Dr. Klaus Hafner, Dipl.-Ing. Bernd Stowasser, Dr. Hans-Peter Krimmer, Stefanie Fischer, Dr. Michael C. Böhm and Prof. Dr. Hans Jörg Lindner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606301

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      To check the influence of substituents on the bonding of the 12π-perimeter of s-indacene, a tetraalkyl derivative, the title compound 1, was synthesized. 1, red needles, is weakly paratropic. Crystal structure analysis and NMR investigations indicate a delocalized or a localized π-electron system with only a small energy barrier between the π-bond isomers.

    2. 9b-Methyl-9bH-benzo[cd]azulene—A Novel Antiaromatic 12π-Electron System (pages 632–633)

      Prof. Dr. Klaus Hafner and Dipl.-Ing. Volker Kühn

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606321

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      The first tricyclic [12]annulene with an unsubstituted perimeter, namely the blue hydrocarbon 2, could be prepared from the azulene derivative 1. Compound 2 proved to be an antiaromatic 12π-electron system par excellence.

    3. Synthesis and Dynamic Properties of Substituted Cyclohepta[ef]heptalene (pages 633–635)

      Prof. Dr. Klaus Hafner, Dr. Günter L. Knaup and Prof. Dr. Hans Jörg Lindner

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606331

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      Cycloheptale[ef]heptalene (pleiaheptalene) is the first peri-annelated [4n]-π-electron system without aromatic partial structure. One of its derivatives that has now been synthesized is the compound 1, R[DOUBLE BOND]Me, which has exclusively the given double bond distribution. In solution an equilibrium is established with a π-bond isomer.

    4. A Stable Monocyclic 1,4-Thiazepine: Synthesis and Characterization of 2,7-Di-tert-butyl-5-methoxy-1,4-thiazepine (pages 635–637)

      Prof. Dr. Kagetoshi Yamamoto, Dipl.-Chem. Shoko Yamazaki, Hiroki Osedo and Prof. Dr. Ichiro Murata

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606351

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      Two tert-butyl groups adjacent to the sulfur atom in the title compound 1 hinder elimination of sulfur with ring contraction. Compound 1 can be obtained in a multistep reaction involving a Beckmann rearrangement and a Pummerer reaction. When 1 is heated in benzene in the presence of PPh3 ring contraction takes place with formation of the pyridine 2.

    5. [U33-Cl)22-Cl)312-AlCl4)36-C6Me6)3][AlCl4]—A Trinuclear Arene Complex of UIII (pages 637–639)

      Prof. F. Albert Cotton, Dr. Willi Schwotzer and Charles Q. Simpson II

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606371

      Donor-acceptor complexes of f-block elements with neutral π-ligands are few in number. It has now been possible to synthesize the trinuclear UIII-title complex from UCl4, AlCl3, C6Me6 and aluminum by a modified Friedel-Crafts reaction. Each U atom is coordinated in a pentagonal bipyramidal fashion by six Cl atoms and C6Me6.

    6. Metallacyclic Four-Membered Ring Systems: Two Independent Routes to Bis(cyclopentadienyl)titanacyclobutabenzene (pages 639–640)

      Dr. Henricus J. R. de Boer, Dr. Otto S. Akkermann, Prof. Dr. Friedrich Bickelhaupt, Prof. Dr. Gerhard Erker, Dipl.-Chem. Peter Czisch, Dr. Richard Mynott, Dr. Julian M. Wallis and Prof. Dr. Carl Krüger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606391

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      Two routes lead to the target: The title compound 2 is formed, both upon reaction of the double Grignard reagent 1 with titanocene dichloride as well as upon reaction of H2C[DOUBLE BOND]PPh3 with thermally generated (aryne)titanocene 3. In the second route, the phenyltitanocene ylide 4 is also formed.

    7. Nickelacyclobutabenzene Compounds by Oxidative Addition of Cyclopropabenzene to Nickel(0) Compounds (pages 640–642)

      Prof. Dr. Richard Neidlein, Dr. Anna Rufińska, Dipl.-Chem. Harald Schwager and Prof. Dr. Günther Wilke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606401

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      The title reaction provides a novel and versatile entry to metallacyclobutabenzene compounds. The products 2 could be characterized both spectroscopically as well as by their reactivity. Thus, when L = nBu3P the reaction with CO2 leads via ring expansion to 3, the hydrolysis product of which was identified as o-methylbenzoic acid.

    8. A 1,2-Diboratabenzene: Lithium Salt and Transition Metal Complexes (pages 642–643)

      Prof. Dr. Gerhard E. Herberich, Dr. Bernd Hessner and Dipl.-Chem. Martin Hostalek

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606421

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      1,2-Bis(dimethylamino)-1,2-diboratabenzene can be isolated as the crystalline Li(tmeda) Salt and structurally chracterized. The diborane(4) 1 affords the 1,2-dibora-4-cyclohexene derivative 2, which upon reaction with lithium tetramethylpiperidide (LiTMP) furnishes 3. The anion of 3 has favorable ligand properties and could be inserted into Ru-sandwich and Rh-tripledecker complexes.

    9. Variable Electron-Donor Ability of Alkyne Ligands—Synthesis and Structure of Carbonyl(η5-cyclopentadienyl)(η2-1-diethylamino-1-propyne)(η1-p-methylphenylketenyl)tungsten (pages 643–644)

      Priv.-Doz. Dr. Fritz R. Kreissl, Dipl.-Chem. Gabriele Reber and Dr. Gerhard Müller

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606431

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      Acetylene ligands are not only capable of functioning as 2e- and 4e-donors, these are merely extreme cases, as has been shown by the characterization of the η1-ketenyltungsten complex 2, which must be described in terms of two resonance structures (2a, b). 2 was obtained in the form of red crystals upon reaction of 1 with 1-diethylamino-1-propyne (R = p-C6H4Me).

    10. 1,3-Diphosphacyclobutadienecobalt(I) Complexes from Phosphaalkynes (pages 644–645)

      Priv.-Doz. Dr. Paul Binger, Dipl.-Chem. Roman Milczarek, Dr. Richard Mynott, Prof. Dr. Manfred Regitz and Dipl.-Chem. Wolfgang Rösch

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606441

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      The first diphosphacyclobutadiene with three-coordinate phosphorus could be stabilized as cobalt-complexed compound 3 by dimerization of the phosphaalkyne 1 in the presence of the cobalt complex 2. If 2 is present in excess, di- and tri-nuclear cobalt complexes are also formed, by coordination of the fragment [(C5H5)(C2H4)Co] to the P atoms of 3.

    11. [{(η5-C5Me5)Co}3C12H 10]—A Complex of Biphenyl with Kekulé Structure (pages 646–647)

      Prof. Dr. Herbert Lehmkuhl, Dr. Hans Nehl, Priv.-Doz. Dr. Reinhard Benn and Dr. Richard Mynott

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606461

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      The biphenyl ligand in the title compound 1 does not behave like an aromatic system with six conjugated double bonds but like a compound with three isolated diene moieties. It is isolable in the form of black crystals upon reaction of [(C5Me5CoCl)2] with PhLi. The proposed structure is based on NMR spectroscopic findings.

    12. A Macrobicyclic Polyphenoxide as Receptor Analogue for Choline and Related Ammonium Compounds (pages 647–649)

      Prof. Dr. Hans-Jörg Schneider, Dipl.-Chem. Detlev Güttes and cand. chem. Ulrich Schneider

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606471

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      The long known condensation of resorcinol with acetaldehyde yields the tetraphenoxide H (R[DOUBLE BOND]CH3). This bowl-shaped host compound is characterized by cyclic hydrogen bridges and delocalized negative charge, which leads to a high symmetry and stability and to the highest bonding constants known so far for methylammonium ions of the choline type and similar derivatives.

    13. Diisopropyl(2,4,6-tri-tert-butylphenylimino)silane—a very Stable, Free Silaimine (pages 649–650)

      Dr. Michael Hesse and Prof. Dr. Uwe Klingebiel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606491

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      Once again we have found bulky substituents that enable the synthesis of a stable compound with a moiety that has virtually been discarded and contradicts the double bond rule. The silaimine 1, synthesized by thermal cleavage of LiCl, is an orange-colored crystalline compound that melts without decomposition at 97–99°C.

    14. Benzotri(imidazole)—a New Ring System Derived from Benzenehexamine (pages 650–651)

      Dr. Bernd Kohne, Prof. Dr. Klaus Praefcke, Thomas Derz, Thomas Gondro and Dr. Felix Frolow

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606501

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      A threefold imidazole ring-closure reaction to give the tetracyclic heterocycle 1 was accomplished by reaction of carboxylic acids with benzenehexamine, which can easily be prepared by hydrogenation of 2,4,6-trinitro-1,3,5-benzenetiamine. According to an X-ray structure analysis 1, R[DOUBLE BOND]C5H11, has a bowl-shaped structure in the crystal.

    15. Si6H6: Is the Aromatic Structure the Most Stable One? (pages 651–652)

      Dr. Alexander Sax and Prof. Dr. Rudolf Janoschek

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606511

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      No! Calculations of the relative stabilities of Si6H6 isomers give a completely different picture from what one is used to in carbon chemistry. Hexasilaprismane 1 is markedly more stable than hexasilabenzene 2, although the resonance energy of the π-electron system of 2 is only about 30% less than that of benzene.

    16. Rearrangement of 4H-1,2,4-Triazolium Salts to 4-Acyl-5-aminoimidazoles (pages 652–653)

      Dr. Costin N. Rentzea

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606521

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      The 4-acyl-5-aminoimidazoles 2 can be synthesized in satisfactory yields in a one-step reaction from the corresponding triazolium salts 1. Six examples (R[DOUBLE BOND]tBu or 2,4-Cl2C6H3, aryl[DOUBLE BOND]p-F-, Cl-, Br-, CF3[BOND]C6H4, 3,4-Cl2C6H3) demonstrate the scope of this reaction (DMF [DOUBLE BOND] dimethylformamide).

    17. Organometallic Derivatives of Epoxides (pages 653–654)

      Dr. Ekkehard Bartmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606531

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      β-Metalated alkoxides are useful synthetic intermediates. The hitherto difficultly accessible species are formed upon reaction of epoxides with alkalimetal or magnesium salts of naphthalene or biphenyl radical anions. In unsymmetrically substituted epoxides a pronounced regioselectivity of the ring opening is found, the orientation of which depends upon the nature of the substituents.

    18. Stereocontrolled Synthesis of Paraconates from β-Lactones; Stereochemistry of Electrophilic Additions to Endocyclic Paraconate-Enolates (pages 655–656)

      Prof. Dr. Johann Mulzer and Dr. Alexander Chucholowski

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606551

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      The addition of electrophiles to paraconate-enolates is controlled purely sterically and not stereoelectronically. This surprising result was found upon reaction of the enolates 1 with alkyl halides and aldehydes, whereby the adducts 2 and 3 are formed stereoselectively in good yields. R1, R2, R3 [DOUBLE BOND] alkyl, aryl.

    19. Isomorphism of Tris(cyclopentadienyl)lutetium(III) and Tris(cyclopentadienyl)scandium(III): An Unexpected Consequence of the Lanthanoid Contraction (pages 656–657)

      Dipl.-Chem. Stefan H. Eggers, Dipl.-Chem. Holger Schultze, Dr. Jürgen Kopf and Prof. Dr. R. Dieter Fischer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606561

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      Not the structure of a lanthanoid(III) homologue resembles that of Cp3Lu(Cp[DOUBLE BOND]C5H5), but rather that of the corresponding Sc compound. This supports the old contention that not La, but Lu should be placed in group 3A (se, Y…) of the periodic system.

    20. Remarks on the Review Article “Replication and Evolution in Inorganic Systems” by Armin Weiss (page 658)

      Prof. Dr. Gustaf Arrhenius, Dr. Alexander G. Cairns-Smith, Prof. Dr. Hyman Hartman, Prof. Dr. Stanley L. Miller and Prof. Dr. Leslie E. Orgel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606581

  3. Book Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Book Review: Vibronic Coupling. By G. Fischer (page 659)

      Horst Köppel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606591

    2. Book Review: Gruppentheorie für Chemiker. By D. Wald (page 660)

      Egbert Keller

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198606601

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