Angewandte Chemie International Edition in English

Cover image for Vol. 29 Issue 9

September 1990

Volume 29, Issue 9

Pages 939–1076

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 9/1990)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199009391

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      The cover picture shows the simulated approach of “golfomycin”, a low-molecular-weight synthetic compound, to double-stranded DNA. Golfomycin, a cyclodecadiynone derivative, was designed to cleave DNA via a diradical mechanism. Although the actual mechanism was different from that expected, golf-omycin indeed cleaved DNA and proved to be cytotoxic (in vitro). The design, synthesis, and testing of golfomycin demonstrate that modern organic chemistry can be much more than just a handmaiden of biology and medicine. Further details on the relatively simple, though ingeniously designed, golfomycin are reported by K. C. Nicolaou et al. on page 1064. The picture was produced by Michael Pique and William Ogilvie and the DNA model by Thomas Maecke, all of the Research Institute of Scripps Clinic.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Gas Chromatographic Separation of Enantiomers on Cyclodextrin Derivatives (pages 939–957)

      Prof. Dr. Volker Schurig and Dr. Hans-Peter Nowotny

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199009393

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      Enantioselective host–guest inclusion accounts for the gas-chromatographic enantiomer separation of unfunctionalized hydrocarbons on cyclodextrin derivatives. On the other hand, the resolution of polar racemic compounds appears to involve many factors. Nonetheless, the range of separable compounds is very broad. Not only mono- and dialcohols, derivatized hydroxy carboxylic acids, sugars, and alkyl halides but also nonpolar alkenes, saturated hydrocarbons (see picture), and metal complexes have been separated into their enantiomers.

    2. The Myelin Membrane of the Central Nervous System—Essential Macromolecular Structure and Function (pages 958–976)

      Prof. Dr. Dr. Wilhelm Stoffel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199009581

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      If the axons of the spinal cord were not myelinated, the spinal cord would have to have the diameter of an oak tree several hundred years old in order to perform as well. This demonstrates the importance of the myelin membrane for the central nervous system, the most important components of which are shown on the right. Modern methods of biochemistry and molecular biology have made it possible in recent years to elucidate the structure of the membrane and to explain myelogenesis. This understanding has led, in turn, to improved therapeutic strategies for the treatment of diseases such as multiple sclerosis, which results in destruction of the myelin sheath.

    3. The Directed Synthesis of Biaryl Compounds: Modern Concepts and Strategies (pages 977–991)

      Dipl.-Chem. Gerhard Bringmann, Prof. Dr. Rainer Walter and Dipl.-Chem. Ralf Weirich

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199009771

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      Biaryls are important not only as pharmacologically active natural products but also as chiral reagents, crown ethers, and host molecules. This importance has been reflected over the past ten years in the large number of new procedures for their synthesis. For example, the key step in the preparation of dioncophyllin A (2 ) is the diastereoselective ring opening of the axial-prostereogenic lactone precursor 1.

    4. Computer Simulation of Molecular Dynamics: Methodology, Applications, and Perspectives in Chemistry (pages 992–1023)

      Prof. Dr. Wilfred F. van Gunsteren and Prof. Dr. Herman J. C. Berendsen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199009921

      At least 109 hours of computing time on a powerful computer would be required to perform an exact computer simulation of protein folding over one-tenth of a second. Despite this discouraging fact, molecular dynamics (MD) simulations have proved extremely useful over the past years, especially when it was necessary to calculate the macroscopic behavior of microscopic/molecular interactions. A fundamental problem in the simulation of molecular systems involves the vast conformational space spanned by all molecular conformations. It is extremely difficult to carry out an efficient search for those regions of global low free energy that are populated at thermal equilibrium. The methodological basis of MD simulations is explained in detail and several (bio)chemical applications are discussed.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Building Blocks for the Synthesis of Enantiomerically Pure Jasmonoids: Synthesis of (+)-Methyl Epijasmonate (pages 1024–1025)

      Prof. Dr. Günter Helmchen, Dipl.-Chem. Andreas Goeke, Dipl.-Chem. Gilbert Lauer, Dipl.-Chem. Matthias Urmann and Dipl.-Chem. Jürgen Fries

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010241

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      Jasmine oil contains only 5% of the active constituent methyl epijasmonate (1a) in equilibrium with methyl jasmonate (1b). Multigram quantities of 1a can be synthesized in a highly diastereoselective fashion from the fumarate of (S)-ethyl lactate and cyclopentadiene. The intermediates thereby obtained can serve as building blocks for the synthesis of nearly all jasmonoids.

    2. Peptide Synthesis under High Pressure (pages 1025–1026)

      Priv.-Doz. Dr. Joachim Gante, Dipl.-Chem. Ulrike Kalthof, Prof. Dr. Frank-Gerrit Klärner and Thomas Weber

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010251

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      Nonactivated amino acid alkyl esters (as ester components) and amino acid Na salts (as amine components) form dipeptides at room temperature under pressures of 7 and 11 kbar [Eq. (a)]. The advantages of this method include the use of inexpensive, readily accessible starting materials and the easy separation of byproducts (alcohols).

    3. How Do Two C[BOND]C Double Bonds Add to One M[BOND]M Triple Bond? Structure and Bonding in Bis (η2-ethylene)hexakis(neopentoxy)ditungsten (pages 1026–1028)

      Dr. Roger H. Cayton, Stephanie T. Chacon, Prof. Malcolm H. Chisholm and Dr. John C. Huffman

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010261

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      Two pseudotetrahedral d-W(OR)32-C2H4) fragments make up the structure of the title compound [W2(OCH2tBu)62-C2H4)2] (1). According to an MO analysis, the structure is governed by the competition between metal–olefin and metal–metal bonds. The novel feature of 1 is the combination of four bridging OCH2tBu, two terminal OCH2tBu, and two terminal η2-C2H4 ligands.

    4. Perchlorinated and Highly Chlorinated meso-Tetraphenylporphyrins (pages 1028–1030)

      Dr. Tilak Wijesekera, Dr. Akiteru Matsumoto, Prof. David Dolphin and Dr. Doris Lexa

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010281

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      The electron-withdrawing chloro substituents in the porphinatoiron(III) compounds 2–6 cause anodic shifts in the half-wave potentials E1/2 relative to that of the unsubstituted compound 1. Substitution on the phenyl rings is less effective than β substitution (R3). The spectroelectrochemically determined stability constants for binding of Cl are high for the β-chlorinated derivatives.

    5. 2,3-Diboratabutadienes and 2-Borataallenes (pages 1030–1032)

      Dr. Monika Pilz, Jürgen Allwohn, Peter Willershausen, Prof. Dr. Werner Massa and Prof. Dr. Armin Berndt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010301

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      Despite a formal negative charge on boron, no LiċB coordination is found in borataallene 1. Instead, the Li ions are coordinated by the aryl C atoms and an allene C atom. In diboratabutadiene 2, one Li ion is also coordinated by aryl C atoms. The other is coordinated by the butadiene unit and two Si methyl groups. Aryl = 2,4,6-Me3C6H2.

    6. Compounds with a Boron–Carbon Triple Bond (pages 1032–1033)

      Jürgen Allwohn, Dr. Monika Pilz, Dr. Ralf Hunold, Prof. Dr. Werner Massa and Prof. Dr. Armin Berndt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010321

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      Resonance structure B is not significantly involved in the π-etectron distribution of the deprotonated borylborataalkynes 1, as shown by structure analysis and NMR spectroscopic data. This finding, together with the fact that the Bsp[BOND]Csp distance found for 1b · 2Et2O is in exact agreement with that calculated for H[BOND]B [TRIPLE BOND] C[BOND]H, supports the presence of a true B[BOND]C triple bond in 1, as shown in A. a, R1 = 2,4,6-Me3C6H2; b, R1 = 2,3,5,6-Me4C6H; R2 = Me3Si.

    7. A Compound with a Boron–Arsenic Double Bond (pages 1033–1035)

      Mark A. Petrie, Steven C. Shoner, Dr. H. V. Rasika Dias and Prof. Philip P. Power

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010331

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      A B[BOND]As distance of 1.926 Å and a considerable restriction of rotation around the central B[BOND]As axis are unequivocal indications of a B[BOND]As π interaction in the arsanediylborate 1. Orange-red crystals of 1 are obtained in 59% yield from MeS2BF and Li2AsPh in THF.

    8. Synthesis and NMR Spectra of 2,3-Dihydro-l,3-methanoindene Derivatives and l,2,3,5-Tetrahydro-l,3-methanopentalene (pages 1035–1037)

      Prof. Dr. Manfred Christl and Dr. Horst Reuchlein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010351

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      2-Lithiobicyclo[2.1.1]hexene, prepared from bicyclo[2.1.1]hexan-2-one, is the key intermediate in an efficient synthesis of interesting bicyclo[2.1.1]hexane derivative such as 1–3. Noteworthy is the reactivity of 3, which acts more as a 2π-electron than as a 4π-electron system toward olefins such as tetracyanoethylene. Furthermore, the new compounds have unusual 13C NMR spectra.

    9. (3,3-Diphenylallenylidene)trimethylphosphanetitanocene: The First Titanocene Carbene Complex with Three Cumulative Double Bonds (pages 1037–1038)

      Prof. Dr. Paul Binger, Dr. Patrik Müller, Dipl.-Chem. Regine Wenz and Dr. Richard Mynott

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010371

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      1,2-Dilithiocyclopropene [RIGHTWARDS ARROW] 1,1-dilithioallene rearrangement results in the formation of compound 2 from 3,3-diphenylcyclopropene (1) and two equivalents of n-butyllithium. Compound 2 reacts further with titanocene dichloride and trimethylphosphane to give the allenylidenetitanocene complex 3. The yields of this one-pot synthesis are 71 %.

    10. An Efficient Route to Linear Conjugated Triepoxides: allo-, galacto-, and altro-Type Trianhydrohexitols (pages 1038–1041)

      Dipl.-Chem. Jürgen Kammerer, Grety Rihs and Prof. Dr. Horst Prinzbach

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010381

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      The 1,2:3,4:5,6-trianhydrohexitols 2–4 of meso-allitol, meso-galactitol, and rac-altritol, respectively, which are not yet accessible from sugar precursors and are attractive C6 building blocks, were prepared from the epoxycyclohexenes 1. A structure analysis was carried out for 3.

    11. Facile Synthesis of 4-Acyl-5-alkyl-2,3-dioxo-2,3-dihydrofurans and Alkylidenebutenolides (pages 1041–1042)

      Prof. Dr. Rolf W. Saalfrank and Dipl.-Chem. Thomas Lutz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010411

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      The use of magnesium chloride as initiator makes it possible to synthesize dihydrofuran-2,3-diones 1 or their tautomers, the alkylidenebutenolides 2, according to (a) in greater than 60% yields. Whether 1 or 2 is isolated depends on the R2 group. All reaction steps are regio- and stereospecific.

    12. Tetraphenylallylsodium Diethyl Ether: A Contact Ion Pair with an Intramolecular Na Sandwich (pages 1042–1044)

      Prof. Dr. Hans Bock, Dipl.-Chem. Klaus Ruppert, Dr. Zdenek Havlas and Prof. Dr. Dieter Fenske

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010421

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      A dibenzenesodium sandwich and an ether “plug” are the salient features of the structure of 1. The structural changes occurring on reduction of tetraphenylallene to 1 are similar to those previously found from MNDO calculations for the reduction of allene. MNDO calculations also offer an explanation for the observed coordination of the sodium ion: the sum of the charges on the two complexing benzene rings is greater than that of an allyl anion center.

    13. Thermal Decomposition of the Nonmetal Octahedron (CIB)4P2 by Elimination of Its PP Octahedral Edge (pages 1044–1046)

      Dr. Bahman Solouki, Prof. Dr. Hans Bock, Prof. Dr. Wolfgang Haubold and Dr. Willi Keller

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010441

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      Above 1300 K, P2 is “expulsed” in a highly selective fashion from the closo-diphosphahexaborane 1. This was shown by PE-spectroscopic investigation of the pyrolysis of 1 under nearly unimolecular conditions. According to approximative calculations of MNDO energy hypersurfaces, the activation proceeds along a narrow potential over a high-lying saddle point, which qualitatively explains the experimental results.

    14. The Proton Catalyzed Transformation of a Cobaltacyclopentadiene into a η4-Cyclobutadiene Complex (pages 1046–1048)

      Lutz Brandt, Prof. Michael Green and Dr. Adrian W. Parkins

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010461

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      H addition to the diene system of 1 gives the complex cation 2, isolated at − 30°C as its SbFmath image or CF3COmath image salt. At − 20°C, 2 rearranges to give the unusual isomer 3, in which one phenyl ring is η2 coordinated. Apparently, intramolecular phosphane addition results in stabilization of the reactive cation 2.

    15. The Structure of Vicinal Pentaketones—X-Ray Structure Investigations and Calculations (pages 1048–1050)

      Prof. Dr. Rolf Gleiter, Dr. Edwin Litterst, Dipl.-Chem. Thomas Oeser and Prof. Dr. Hermann Irngartinger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010481

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      A helical conformation and thus a sterically unfavored structure characterizes the pentaketones 1 and 2. A simple model reveals that the decisive factor is the minimization of the total dipole moment.

    16. Synthesis of a β-Mannosyl-Chitobiosyl-Asparagine Conjugate—a Central Core Region Unit of the N-Glycoproteins (pages 1050–1051)

      Dipl.-Chem. Wolfgang Günther and Prof. Dr. Horst Kunz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010501

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      The correct β-glycosidic linkage between mannose and chitobiosyl-asparagine residues in N-glycoproteins was achieved synthetically for the first time in the construction of 1. Decisive is the intramolecular nucleophilic substitution in 2; the product of this reaction was transformed, via a trisaccharide and a trisaccharide isothiocyanate, into the asparagine derivative 1.

    17. A Novel Type of Ring Contraction as Non-Enzymatic Step in the Later Stages of the Biosynthesis of Urdamycin H (pages 1051–1053)

      Dr. Jürgen Rohr

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010511

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      Intramolecular ring closure and oxidative decarboxylation following lactone ring opening allow urdamycin H (2) to be synthesized from urdamycin C (1) in a nonenzymatic process. This was the result of biosynthetic studies and model reactions on the urdamycin system.

    18. Direct Electron Transfer between Carbon Electrodes, Immobilized Mediator and an Immobilized Viologen-accepting Pyridine Nucleotide Oxidoreductase (pages 1053–1055)

      Dr. Helmut Günther, Dr. Antonios S. Paxinos, Dipl.-Chem. Michael Schulz, Dr. Cees van Dijk and Prof. Dr. Helmut Simon

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010531

      The electron transfer between electrodes and the redox-active prosthetic groups of oxidoreductases is usually too slow to be measurable, unless a mediator is used. Now, a mediator and the enzyme have been covalently immobilized on a functionalized carbon electrode. The electrons can thus flow from the cathode to the oxidoreductase via a “molecular wire”. The use of carbon felt having a larger inner surface area as electrode affords current densities at the lower end of the range used in industrial processes.

    19. Dependence of the Magnetic Superexchange on the CrċCr Distance in Dinuclear Chromium (II) Complexes (pages 1055–1057)

      Ursula Bossek, Prof. Dr. Karl Wieghardt, Dr. Bernhard Nuber and Prof. Dr. Johannes Weiss

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010551

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      The spins of unpaired electrons in binuclear CrIII complexes containing the structural element A are coupled antiferromagnetically. Measurement of the temperature-dependent susceptibilities showed that the contribution of this coupling is inversely proportional to the twelfth power of the intramolecular distance between the Cr ions (|J| ∼ r−12).

    20. Ring-Opening of a Bicyclo[3.2.0]hepta-1,3-dienyl-cobalt(I) Complex Followed by Cycloaddition (pages 1057–1059)

      Dr. Holger Butenschön

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010571

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      The four-membered ring of the cobalt complex 1 is opened at only 200°C. The resulting allyl diene system 2 can be trapped by [2 + 4] cycloaddition with dienophiles to give cycloadducts such as 3 in good yields. The stereochemistry of the cycloadducts is strongly influenced by the coordination behavior of the dienophile. L = tetraphenylcyclobutadiene, E = COOCH3.

    21. Azadiboriridine-Borane: a Non-Classical Acid-Base Adduct (pages 1059–1060)

      Prof. Dr. Peter Paetzold, Burkhard Redenz-Stormanns, Dr. Roland Boese, Michael Bühl and Prof. Dr. Paul von Ragué Schleyer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010591

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      The B[BOND]B bond is the basic center in the azadiboriridine 1. This is shown by the observation that reaction with the Lewis acid BH3 affords the novel, nonclassical bicyclobutane derivative 2 in 95% yield. According to electron-counting rules, 2 may also be regarded as a nido derivative of a trigonal-bipyramidal compound. Ab initio calculations on the parent compound nido-NB3H6 confirm the experimental findings (R = tBu).

    22. Mechanism of the Cycloaddition of Bicyclo[2.1.0]pent-2-ene: a Non-concerted Homo-Diels-Alder Reaction (pages 1061–1062)

      Prof. Dr. Frank-Gerrit Klärner and Dipl.-Chem. Manfred Naumann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010611

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      Tetracyanoethylene adds to bicyclo[2.1.0]pentenes 1 a, b in a stereospecific endo fashion. Therefore, the formal Diels–Alder reaction, like the [σ2 + π2] cycloaddition with bicyclo[2.1.0]pentane, presumably proceeds in two steps. The reaction with dicyanofumaric and dicyanomaleic esters is nonstereospecific with respect to the olefin components, thus supporting this supposition.

    23. Nickel-Catalyzed Cyclodimerization of Hexapentaenes: [4]Radialenes and [5]Radialenones with Cumulated Double Bonds (pages 1062–1064)

      Prof. Dr. Masahiko Iyoda, Yoshiyuki Kuwatani, Prof. Dr. Masaji Oda, Prof. Dr. Yasushi Kai, Prof. Dr. Nobuko Kaneshisa and Nobutami Kasai

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010621

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      The size of the alkyl substituents of [5]cumulenes such as 1 governs their nickelcatalyzed cyclodimerization. The sterically encumbered compound 1 affords the radialenone 2 and the radialene 3. Head-to-tail coupling is observed for smaller substituents. The cyclopentanone ring in 2 is nearly planar.

    24. Golfomycin A, a Novel Designed Molecule with DNA-Cleaving Properties and Antitumor Activity (pages 1064–1067)

      K. C. Nicolaou, Golfo Skokotas, S. Furuya, H. Suemune and D. Colette Nicolaou

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010641

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      Retroaldol reaction, propargyl–allenyl isomerization, and [4 + 2] cycloaddition are the steps involved in the reaction of the title compound 1 with 1,8-diazabi-cyclo[5.4.0]undec-7-ene at room temperature in THF. The product 2, like 1, reacts readily with nucleophiles such as methyl thioglycolate. The biological activity of these compounds is presumably due to this reactivity.

    25. Synthesis and Cycloadditions of Monomeric Selenobenzophenone (pages 1067–1068)

      Prof. Dr. Gerhard Erker, Dipl.-Chem. Regina Hock, Prof. Dr. Carl Krüger, Dipl.-Chem. Stefan Werner, Prof. Dr. Frank-Gerrit Klärner and Dr. Uwe Artschwager-Perl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010671

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      Selenobenzophenone (1), prepared from Ph2C [DOUBLE BOND] PPh3 and Se, is monomeric in solution and dimeric in the solid state. Cycloadditions of dienes to 1 proceed at room temperature under normal pressure as multistep reactions, as shown by the exclusive formation of cis-2 from both trans, trans- and cis, trans-hexa-2,4-diene. When the pressure is raised to about 12 kbar, cis, trans-hexadiene affords 60% of trans-2, the product of the concerted hetero-Diels–Alder reaction.

  3. Book Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Book Review: Chemistry of Tin. Edited by P. J. Harrison (pages 1072–1073)

      Wilhelm Paul Neumann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199010722