Angewandte Chemie International Edition in English

Cover image for Vol. 19 Issue 6

June 1980

Volume 19, Issue 6

Pages 411–494

Currently known as: Angewandte Chemie International Edition

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. The Kinetic and Mechanistic Evaluation of NMR Spectra. New analytical methods (18) (pages 411–428)

      Prof. Dr. Gerhard Binsch and Prof. Dr. Horst Kessler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004113

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      Dynamic NMR spectroscopy (DNMR spectroscopy) has long served the experimental chemist as a convenient diagnostic tool for qualitative detection of molecular-level dynamic processes. It is also suitable for quantitative determination of activation energies and entropies. Moreover, DNMR spectroscopy can frequently also provide detailed mechanistic information which is inaccessible by other methods.

    2. Towards an Understanding of the Carbon-Carbon Bond (pages 429–440)

      Prof. Dr. Christoph Rüchardt and Dr. Hans-Dieter Beckhaus

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004291

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      The influence of the substituents on the strength of CC bonds has been investigated by thermolysis of highly branched alkanes and their cyano- and phenyl derivatives. A linear relationship is found to exist between the free energy of activation of homolysis and the ground state strain energy for each of these classes of compounds. Thus it has proved possible to quantitatively separate steric and electronic effects in the cleavage of the C[BOND]C bond. Novel qualitative information is also obtained by this approach.

    3. The Role of Pyridoxal Phosphate in the Catalysis of Glycogen Phosphorylases (pages 441–455)

      Prof. Dr. Ernst J. M. Helmreich and Dr. Helmut W. Klein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004411

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      Pyridoxal phosphate(1), present as essential cofactor in all glycogen phosphorylases, is a vitamin B6 derivative. Reduction experiments show that these enzymes act differently from “classical” (1)-dependent phosphorylases. Can it be that the phosphate group participates as dianion in the catalytic process? This dianion has been detected by 31P-NMR spectroscopy in the catalytically active forms of glycogen phosphorylases.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. One-Pot Synthesis of Substituted Semibullvalenes (pages 456–457)

      Dörte Paske, Richard Ringshandl, Ingeborg Sellner, Dipl.-Chem. Heinz Sichert and Prof. Dr. Jürgen Sauer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004561

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      A very facile route to substituted semibullvalenes(2), which is still open to further development, consists in the one-pot synthesis from tetrazines and the cyclopropene derivative (1) (R = CO2Me, Ph, Me).

    2. Relation between Orbital Character and Reaction Product in the Reaction of Benzvalene and Homobenzvalene with Thiophenol (pages 457–458)

      Prof. Dr. Manfred Christl, Dipl.-Chem. Reinhard Lang, Rainer Herbert and Gertrud Freitag

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004571

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      In order to compare the reactivity of the bicyclobutane system and the C[DOUBLE BOND]C double bond towards thiols, both benzvalene (1) and homobenzvalene (2) were allowed to react with thiophenol. Compound (1) is attached at the double bond and (2) at the bicyclic system, i.e. at the sites of localization of the HOMO.

    3. Oxidation Reactions of Benzvalene: Ozonolysis, cis-Hydroxylation, Epoxidation, and Singlet Oxygen Addition (pages 458–459)

      Dipl.-Chem. Hartmut Leininger and Prof. Dr. Manfred Christl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004581

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      Progress in the synthesis of endo,endo-disubstituted bicyclo[1.1.0]butanes such as (2) was achieved on reaction of benzvalene (1) with classical oxidizing agents. (1) is also suitable as a starting material for synthesizing other small-ring polycycles with bicyclobutane partial structures.

    4. Indole Pigments from the Fruiting Bodies of the Slime Mold Arcyria denudata (pages 459–460)

      Prof. Dr. Wolfgang Steglich, Dipl.-Chem. Bert Steffan, Dipl.-Chem. Lothar Kopanski and Dr. Gerd Eckhardt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004591

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      An oxepin derivative has surprisingly been detected as a constituent of a slime mold. Apart from the red dye (1), four yellow or red hydroxylated dyes are also obtained which all lack the oxepin O atom.

    5. Sequence Analysis of Ergochrome-Biosynthesis by Competitive Incorporation (pages 460–461)

      Prof. Dr. Burchard Franck, Dr. Gerhard Bringmann and Dr. Georg Flohr

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004601

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      Proof of alternative intermediates in the biosynthesis of natural products is provided by competitive incorporation. For example, it has been demonstrated that in the biosynthesis of ergochrome the OH group on C-4 is introduced after oxidative ring opening of (1).

    6. Citreoviridins from Aspergillus terreus (pages 461–462)

      Prof. Dr. Burchard Franck and Dr. Henning-Peter Gehrken

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004611

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      Citreoviridin A (1a), one of the most dangerous mycotoxins, has ben found in extremely high concentration in the mold Aspergillus terreus. This fungus, one of the commonest organisms occurring in soil and on grain and sugar-containing foodstuffs, is also utilized in biotechnology. Compound (1a) is accompanied by similar metabilites.

    7. 2-Azabarrelenone and 3-Methoxy-2-azabarrelene (pages 463–464)

      Prof. Dr. Rudolf Gompper and Dipl.-Chem. Axel Schmidt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004631

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      Homoallylic interactions can be studied with the aid of the 2-azabarrelenone (1), a potential starting material for the synthesis of 2-azabarrelene. Its methylation leads to (2) whose lower stability could reflect and antiaromatic effect.

    8. Brominations with N-Bromosuccinimide: Solvent and Selectivity (pages 464–465)

      Dr. Werner Offermann and Prof. Dr. Fritz Vögtle

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004641

      Correlations of the selectivity κ of a reaction with the refractive index n of the solvent used are new in physical organic chemistry. Such a relationship has been discovered on bromination of three toluene derivatives with NBS in ten different solvents; deviations were found for the eleventh solvent CCl4.

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    9. Thermal Decarboxylation of β-Lactones: Steric Hindrance of Mesomerism as Indication of a Zwitterionic Intermediate (pages 465–466)

      Dr. Johann Mulzer, Dipl.-Chem. Matthias Zippel and Gisela Brüntrup

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004651

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      The stereospecific synthesis of olefins is frequently accomplished by decarboxylation of β-lactones. Kinetic studies on cis-trans-isomeric β-lactones have now shown that an intermediate Z is involved; Z can be regarded as heterotetramethylene.

    10. 2-Thietanimines from α-Deprotonated β-Lactones and Phenyl Isothiocyanate—A Novel Four-Membered Ring/Four-Membered Ring Recyclization (pages 466–468)

      Dr. Johann Mulzer and Thomas Kerkmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004661

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      The rare class of thietanimines (4) has expanded. The key step of the promising new synthesis is the recyclization (2)[RIGHTWARDS ARROW](3).

    11. (1,2,5,6-η-1,5-Cyclooctadiene)- (1,2,7,-η-7-methylbenzyl)(7,8-η-styrene)rhodium(I)—Antarafacial Fluctuation of the Benzyl Ligand and Temperature-Dependent Coordination of Styrene (pages 468–469)

      Dr. Hans-Otto Stühler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004681

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      A fluxional η3-benzyl ligand, as is found in the new rhodium(I) complex (1), is stell a rarity. Its antarafacial fluctuation, detected by NMR spectroscopy above −40°C, is the first of its kind; it can only proceed via a form with Ph—Cbenzyl σ-bond. Only the “σ form” exists at −100°C.

    12. Liquid Chromatography of Enantiomers: Determination of Enantiomeric Purity in Spite of Extensive Peak Overlap (pages 469–470)

      Prof. Dr. Albrecht Mannschreck, Dr. Mladen Mintas, Dr. Georg Becher and Georgine Stühler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004691

      A new approach to the determination of enantiomeric purity P is based on the known technique of liquid chromatography on chiral phases, such as triacetyl-cellulose. Interfering overlapping or fusion of peaks are overcome by simultaneous measurement of absorbance A and rotation α as functions of the volume eluted (υ)· C+ is determined graphically.

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    13. Quantitative Separation of the Enantiomeric Pairs of the Pheromone 2-Ethyl-1,6-dioxaspiro[4.4]nonane by Complexation Chromatography on an Optically Active Metal Complex (pages 471–472)

      Dipl.-Chem. Bernhard Koppenhoefer, Dipl.-Chem. Klaus Hintzer, Dipl.-Chem. Roland Weber and Prof. Dr. Volker Schurig

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004711

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      On use of a new chiral separating phase, complexation gas chromatography effectively resolved the synthetic aggregation pheromone of Pityogenes chalcographus on a nickel (II) bis((R)-pulegonate) complex into its four configurational isomers (see right, R = C2H5).

    14. A Novel Entry to Brefeldin A (pages 472–473)

      Dipl.-Chem. Yetkin Köksal, Dipl.-Chem. Peter Raddatz and Prof. Dr. Ekkehard Winterfeldt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004721

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      The total synthesis of the macrolide antibiotic brefeldin A(2) has been accomplished, starting from cyclopentenyl acetate (1). Successive Michael addition to (1) permitted construction of the trans-disubstituted cyclopentanone system

    15. Euglenapterin—An Unusual New Natural Pteridine Derivative from Euglena gracilis (pages 473–474)

      Dipl.-Chem. Manfred Böhme, Prof. Dr. Wolfgang Pfleiderer, Prof. Dr. Erich F. Elstner and Dr. Wilhelm J. Richter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004731

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      The first example of a natural pterin with a 2-(dimethylamino) group is euglenapterin (1), R[DOUBLE BOND]H. The accompanying substances, the 3′-phosphate (1), R = PO3H2, and the 2′,3′-cyclophosphate, also show this structural feature.

    16. Ozonolysis of 1,2-Dichloroacenaphthylene (pages 474–475)

      Dr. Helmut Seltzer, Dr. Siegmar Gäb and Prof. Dr. Friedhelm Korte

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004741

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      The first primary ozonide which can be isolated as a result of its exceptional stability, has been generated from 1,2-dichloroacenaphthylene and characterized as (1). The normal ozonide (2) formed by rearrangement of (1) appears as side-product.

    17. Differentiation between Chiral Pheromone Analogues by Chemoreceptors (pages 475–477)

      Prof. Dr. Hans Jürgen Bestmann, Dipl.-Chem. Hans Ludwig Hirsch, Dipl.-Chem. Hans Platz, Marlies Rheinwald and Dr. Otto Vostrowsky

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004751

      Insects can distinguish between the object and mirror image of chiral analogues of their (achiral) pheromones; thus the relative activities of (natural) (1):(R)-(2): (R, S)-(2): (S)-(2) were 100:10:1:0.1 (electroantennogram test). These findings support the idea that the pheromone molecule is incorporated as a defined conformation into the receptor region.

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    18. Intercalation Complexes of Metallocenes in Iron Oxide Chloride (pages 477–478)

      Dr. Hartwig Schäfer-Stahl and Dipl.-Chem. Raimund Abele

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004771

      Assumption of “free” electrons in the intercalation complex (1) of FeOCl and ferrocene rationalizes the finding that the high-spin Fe3+ state of the FeOCl host lattice is retained on intercalation of the guest molecule (Mössbauer spectrum), while the Mössbauer absorptions of ferrocene disappear completely. The conductivity of the crystal also supports formulation as (1).

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    19. Catalysis of Hydroformylation by Co4(CO)8−x2-CO)2(PPh3) x4-PPh)2, x = 0 or 2: Clusters as Catalysts (pages 478–479)

      Prof. Dr. Charles U. Pittman Jr., Gary M. Wilemon, W. Dean Wilson and Dr. Robert C. Ryan

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004781

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      That clusters, e.g. (1), rather than their mononuclear fragments act as catalysts has now been established in the hydroformylation of 1- and 2-pentene. The influence of added phosphanes on the reaction rate and the ration of normal to branched products rule out decomposition of (1).

    20. Extreme 13C-NMR Data as Information on Organometal Radicals (pages 479–480)

      Prof. Dr. Frank H. Köhler, Dipl.-Chem. Karl-Heinz Doll and Dr. Wolfram Prössdorf

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004791

      The utility of 13C-NMR spectroscopy in the study of organometallic radicals has been demonstrated for substituted nickelocenes. The shifts and halfwidths, as well as their variation, permit structural elucidation of radicals where ESR fails, and provide indications, e.g. of the number of unpaired electrons and their incorporation in various orbitals, and even of isotope effects.

    21. N-Isocyanoiminotriphenylphosphorane: Synthesis, Coordination Chemistry, and Reactions at the Metal (pages 480–481)

      Dipl.-Chem. Bernd Weinberger and Prof. Dr. Wolf Peter Fehlhammer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004801

      A storage form of N-isocyanides, e.g. isodiazomethane CNNH2, and a new complex ligand are two applications of the surprisingly stable N-isocyaniminophosphorane (1). It is readily accessible by the route shown below.

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    22. B8S16—An “Inorganic Porphine” (pages 481–482)

      Prof. Dr. Bernt Krebs and Dipl.-Chem. Hans-Ulrich Hürter

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004811

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      The extremely hydrolysis-sensitive compound (BS2)8, obtained by fusion of a mixture of B2S3 and S8in vacuo (300/100°C), has been found by X-ray structure analysis to be a planar porphine analogue. A second synthetic route starts from pre-formed five-membered rings.

    23. Hexakis(dimethylamino)cyclohexaborane, a Boron(I) Compound without Electron Deficiency (pages 482–483)

      Prof. Dr. Heinrich Nöth and Dr. Hans Pommerening

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004821

      A B6 ring with a chair conformation is present in the title compound (1) which crystallizes from distillation residues obtained on dehalogenation of [(CH3)2N]2BCl. (1) is the first homocycle of boron and also the first boron (I) compound not to exhibit electron deficiency.

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    24. Boron Trifluoride: Crystal Structure of a Metastable Phase (pages 483–484)

      Prof. Dr. Dietrich Mootz and Dipl.-Chem. Michael Steffen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004831

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      The “simple” molecule BF3 proves to have a surprising crystal structure which differs fundamentally from that of other boron trihalides. A stereopicture shows the packing of the molecules in their crystal.

    25. The (Ph4C4GeMe)Fe(CO)3 Cation: Synthesis, Structure, and Bonding (pages 484–485)

      Prof. Dr. Peter Jutzi, Dr. Alfons Karl and Doz. Dr. Peter Hofmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004841

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      Only a formal analogy exists between [(η5-C5H5)Fe(CO)3]+ and [(C4GeR5)Fe(CO)3]+, as demonstrated by the synthesis of the title compound: incorporation of the heteroatom leads to considerable structural changes. This is in agreement with MO calculations.

    26. An Experimental and Theoretical Study of the Degenerate Carbon Skeleton Isomerization of the Cyclopentyl Cation in the Gas Phase (pages 485–487)

      Dipl.-Chem. Wilfred Franke, Prof. Dr. Helmut Schwarz, Helga Thies, Dr. Jayaraman Chandrasekhar, Prof. Dr. Paul von Ragué Schleyer, Prof. Dr. Warren J. Hehre, Prof. Dr. Martin Saunders and Gray Walker

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004851

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      The non-classical pyramidal cation(4) provides a rational explanation of all the phenomena observed on mass-spectrometic degradation of the cyclopentyl cation (1). On generation from (2a), (2b), (3a), or (3b) (• = 13C), (1) always gives 13C2H4, 13C12CH4, 12C2H4 in the ratio of 10:60:30, i.e. all the C atoms must have become statistically equivalent prior to elimination of ethylene from (1). MINDO/3 calculations show degradation to proceed via the cations (4) and (5).

    27. Allylic Compounds of Magnesium, Lithium, and Potassium: σ- or π-Structures? (pages 487–489)

      Prof. Dr. Manfred Schlosser and Chem. techn. Manfred Stähle

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004871

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      σ-Bonds in allyl-MgBr, non-symmetrical π-bonds and symmetrical π-bonds, respectively, in allyl-Li and allyl-K compounds—these are the grossly simplified NMR findings obtained in solution by the isotopic perturbation technique.

    28. The First “Small Ring” in Fluorometalates: Ba6F4(F4AlF2/2)4=“Ba3Al2F12 (pages 489–490)

      Prof. Dr. Rainer Domesle and Dr. Rudolf Hoppe

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004891

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      A new inorganic “ring”—the tetrameric structural unit [(F4/1AlF2/2)4]—has been detected in Ba3Al2F12. Polynuclear or cyclic fluorometalates were formerly unknown.

    29. Zintl Phases with Complex Anions: Sr3Si2As4 and Sr3Ge2As4 (pages 490–491)

      Dr. Brigitte Eisenmann and Prof. Dr. Herbert Schäfer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004901

      Sr3Si2As4 and Sr3Ge2As4 can be regarded as transition forms between salts of complex anions and ternary intermetallic compounds; they have now been synthesized for the first time. Both compounds contain differently linked one-dimensional, infinite anions with As3Si[BOND]SiAs3 and As3Ge[BOND]GeAs3 structural units.

    30. Catalytic Graphite-Intercalation with Alkali Metals in Solution (pages 491–492)

      Prof. Dr. Hans-Friedrich Klein, Dipl.-Chem. Joachim Gross and Doz. Dr. Jürgen O. Besenhard

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004911

      A new route to graphite inclusion complexes of alkali metals utilizes the reversible reduction of cobalt(0) catalysts. Thus KC8, RbC8 and CsC8 can be synthesized from alkali metals and graphite in pentane at 25°C in the presence of Co(C2H4) (PMe3)3.

    31. Nonstoichiometric Alkali Metal Titanium Sulfides with Channel Structure (pages 492–493)

      Prof. Dr. Robert Schöllhorn, Dipl.-Chem. Wolfgang Schramm and Priv.-Doz. Dr. Dieter Fenske

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.198004921

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      An electronic/ionic conductor suitable in principle for use as electrode material in secondary batteries is K0.3T3S4. The K+ ions (“⊕”) in the lattice made up of TiS6 octahedra (channel structure) are highly mobile at 20°C.

  3. Book Reviews

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