Angewandte Chemie International Edition in English

Cover image for Vol. 33 Issue 3

February 18, 1994

Volume 33, Issue 3

Pages 245–363

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1994)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199402431

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      The cover picture shows the topology of the transition state of a 1,3-dipolar cycloaddition and of the addition of methylene to bicyclobutane. Although the reactions appear very different at first glance, they both profit from the same type of aromatic stabilization in the transition state. The topology of the carbene reaction can be derived from that of the pericyclic reaction by constriction. Alongside pericyclic and polar reactions (SN2,E2, etc.), reactions with coarctate transition states form a third, hitherto never consistently characterized class of concerted reactions in organic chemistry, which includes several hundred addition, rearrangement, and elimination reactions. Theoretical insight into these reactions allows the prediction of mechanisms and stereochemistry as well as the rational design of new representatives of this class of reactions. R. Herges reports more on this subject on p. 255ff.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    7. New Books
    1. Organizing Principle of Complex Reactions and Theory of Coarctate Transition States (pages 255–276)

      Priv. Doz. Dr. Rainer Herges

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199402551

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      The simultaneous breaking and making of two bonds at one reaction center characterizes “complex reactions”. One example, for instance, is the addition of carbene to bicyclobutane [Eq. (a)]. The formal similarities of these reactions can be attributed to a common reaction principle that enables the prediction of mechanistic details and assists in the categorizing of known reactions of this type. Even more interesting, this principle can suggest novel examples in the class of complex reactions.

    2. Protein Structure Determination with Three- and Four-Dimensional NMR Spectroscopy (pages 277–293)

      Dr. Hartmut Oschkinat, Dipl.-Chem. Thomas Müller and Dipl.-Chem. Thorsten Dieckmann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199402771

      Simplify with more dimensions—this could be the slogan to popularize the application of three- and four-dimensional NMR spectroscopy for the structure determination of macromolecules in solution. Although the time required to measure multidimensional spectra is substantial, the resolution of overlapping signals and the information in these spectra is impressive. This review focuses on the application of the new techniques for the structure determination of proteins having molecular weights of up to 35 kDa.

    3. Time-Resolved Photoacoustic Calorimetry: From Carbenes to Proteins (pages 294–302)

      Prof. Kevin S. Peters

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199402941

      Listening to molecules react, and that with a time resolution as high as 1 ns, is possible with the technique described here for photoinduced reactions. Thermodynamic and kinetic data for reactive species in solution can be obtained quite easily. Photoacoustic calorimetry has been used to investigate the kinetics of the quenching of triplet benzophenone with 2,3-dimethyl-2-butene, the strain energy of trans-1-phenylcyclohexene, and the bleaching of rhodopsin under approximately physiological conditions.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    7. New Books
    1. Chromium Carbene Complexes in Organic Synthesis: Recent Developments and Perspectives (pages 303–305)

      Priv.-Doz. Dr. Hans-Günther Schmalz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403031

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      Unexpected reaction pathways and products are apparently not the exception for reactions of Fischer carbenes, and full recognition of the whole potential of this type of complex in organic synthesis is still long way off. Among the classic synthetic applications is the Dötz reaction. One of the many new transformations is the successive reaction of complexes 1 with HNMe2 and pent-1-yne to give cyclopenta[b]pyran 2 and the fulvene complex 3.

    2. A New Application of Modified Peptides and Peptidomimetics: Potential Anticancer Agents (pages 305–307)

      Dr. Rob M. J. Liskamp

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403051

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      Potent competitive inhibitors of oncogenic Ras proteins include modified peptides and peptidomimetics such as 1 and 2, respectively. They prevent the attachment of these mutated proteins to the cell membrane and the resulting unregulated cell proliferation and malignant transformation. This opens new perspectives for the development of anticancer agents, since oncogenic forms of the ras genes, which encode these proteins, frequently occur in human cancer cells.

  3. Correspondences

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    7. New Books
    1. Rationally Designed Inorganic Catalysts for Environmentally Compatible Technologies (pages 308–311)

      Sir. John Meurig Thomas and Prof. Dr. Kirill Ilyich Zamaraev

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403081

      “Catalysis research is not black magic!” maintain proponents of rational design in catalysis research, in response to the assertion made by R. Schlögl (Angew. Chem. Int. Ed. Chem.1993, 32, 381–383) that the development of practical catalysts is still dependent on empirical facts. A number of industrial processes that depend on finely tuned catalysts are cited in support of their premise. In his reply Schlögl restates his thesis and encourages the productive cooperation of “scientific” and “intuitive” approaches to catalyst design.

    2. Reply (pages 311–312)

      Prof. Dr. Robert Schlögl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403111

      “Catalysis research is not black magic!” maintain proponents of rational design in catalysis research, in response to the assertion made by R. Schlögl (Angew. Chem. Int. Ed. Chem.1993, 32, 381–383) that the development of practical catalysts is still dependent on empirical facts. A number of industrial processes that depend on finely tuned catalysts are cited in support of their premise. In his reply Schlögl restates his thesis and encourages the productive cooperation of “scientific” and “intuitive” approaches to catalyst design.

  4. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    7. New Books
    1. The Effect of Fusion of Angular Strained Rings on Benzene: Crystal Structures of 1,2-Dihydrocyclobuta[a]cyclopropa[c]-, 1,2,3,4-Tetrahydrodicyclobuta[a,c]-, 1,2,3,4-Tetrahydrodicyclobuta[a,c]cyclopropa[e]-, and 1,2,3,4,5,6-Hexahydrotricyclobuta[a,c,e]benzene (pages 313–317)

      Priv. Doz. Roland Boese, Dipl.-Ing. Dieter Bläser, Prof. Dr. W. Edward Billups, Dr. Michael M. Haley, Dipl.-Chem. Andreas H. Maulitz, Debra L. Mohler and Prof. Dr. K. Peter C. Vollhardt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403131

      Thumbnail image of graphical abstract

      Noticeable deformations of the benzene framework caused by annelation with strained rings are observed in the crystallographic studies on 1–4. These are the most strained benzene derivatives yet known. The angles at the sp2 carbon atoms in 1 and 3 indicated by an arrowhead are the largest known: 176.9 and 174.9°, respectively. Molecules 2 and 4 display a slight bond length alternation in the arene moiety (0.010–0.023 Å).

    2. Competitive Generation of C[BOND]H and C[BOND]Si Bonds by Reductive Elimination: Formation of Silametallacycles by Metalation of Silyl Ligands (pages 317–319)

      Dr. Michael Aizenberg and Prof. Dr. David Milstein

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403171

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      Exclusive reductive elimination of methane occurs from the iridium complexes 1 and 2 on heating. This leads to the formation of new five-membered silametallacycles by metalation at the δ position of an OEt substituent and to new four-membered silametallacycles by orthometalation, respectively; in contrast, complex 3 eliminates both methane and Et3MeSi in a competitive reaction. The question whether C[BOND]H or C[BOND]Si elimination takes place in catalytic processes such as hydrosilation is thus also dependent on the nature of the substituents on the silyl ligand. L[DOUBLE BOND]PMe3.

    3. Strategies for Nonmacrocyclic Polythioether Ligands: New Pentacoordinating Architectures (pages 319–321)

      Dr. John M. Desper and Prof. Samuel H. Gellman

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403191

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      CuII ions form exclusively 1:1 complexes with polythioethers 1 and 2, which have a central, cis-disubstituted thiane and thiepane unit, respectively. In contrast, an acyclic polythioether analogue forms higher order complexes. These results indicate that nonmacrocyclic thioethers may also serve as effective chelating ligands. The stereospecific synthesis of 1 and 2 also points the way to novel thiacryptands.

    4. 18-, 20-, and 22-Membered Dimetallaortho-, -meta-, and -para[7.7]cyclophanes—The First Typical Metallaphanes (pages 321–323)

      Prof. Dr. Ekkehard Lindner, Dipl.-Chem. Walter Wassing, Dr. Riad Fawzi and Manfred Steimann

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403211

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      The incorporation of transition metals in cyclophane frameworks can be achieved by using the “bistriflate method”, as illustrated for the first time with 1 in which [M] is Os(CO)4 or Fe(CO)4. The metal complex fragments are reactive centers. They provide a simple route to macrocyclic diketones by their reductive elimination following CO insertion into the M[BOND]C σ bonds. This reaction was studied quantitatively for [M] [DOUBLE BOND] Fe(CO)4 in the synthesis of 2.

    5. Difluoromethyl Compounds of Chalcogens: A NMR Study of the Reactions of Cd(CF3)2·2MeCN and ZnBr(CF3)·2MeCN with Dialkyl Chalcogenides and Boron Trifluoride (pages 323–325)

      Prof. Dr. Dieter Naumann, Dr. Regina Möckel and Dr. Wieland Tyrra

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403231

      CF2H derivatives of the chalcogens oxygen, sulfur, selenium, and tellurium form selectively in the carbenoid reactions of Cd(CF3)2 or Zn(CF3)Br with dimethyl or diethyl chalcogenides and boron trifluoride [Eq. (a) below is one example]. Onium ions such as [Et2SCF2H]+ were identified as intermediates by NMR spectroscopy.

      • equation image
    6. Synthesis and Structure of an Oxovanadium(V)—Organophosphonate Cluster Encapsulating a Chloride Ion: [ClV7O12(O3PC6H5)6]2− (pages 325–327)

      Yuan-Da Chang, Jose Salta and Prof. Jon Zubieta

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403251

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      A hollow sphere, constructed from VO5 square pyramids and PhPO3 tetrahedra, which encapsulates a chlorine atom—this is an apt description of the anion in 1 (structure shown on the right). At first glance this anion, with its spheroidal structure, appears similar to known polyoxoanions; however, closer inspection reveals the striking structural similarities to analogous binuclear building blocks and to the layered solid VO(O3PR), H2O, which extend beyond purely topological relationships to chemical behavior.

    7. Macrotricyclic Borane—Amine Adducts: The First Uncharged Synthetic Host Compounds Without Lewis Acid Character, for Anionic Guests (pages 327–329)

      Dr. Karin Worm, Prof. Dr. Franz P. Schmidtchen, Dr. Annette Schier, Dr. Andrea Schäfer and Prof. Dr. Manfred Hesse

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403271

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      Anions as guests in electroneutral host compounds that have no Lewis acid character—this has been achieved for the first time. The borane–amine adduct 1 functions as host, and examples of guests are Cl, I, and CN. Prerequisite for the supramolecular inclusion of the anions is the exact preorganization of the strong B[BOND]N dipoles. X[DOUBLE BOND][BOND](CH2)math image

    8. Complex-Stabilized Alkynyl and Cycloalkenyl Isocyanides (pages 330–332)

      Dipl.-Chem. Rainer Kunz and Prof. Dr. Wolf P. Fehlhammer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403301

      The electrophilic N-alkynylation of cyano ligands by alkynyliodonium salts provides a convenient route to metal-coordinated forms (1a–c) of the “interstellar” ethynyl isocyanide 2a (which can only be isolated in trace amounts in the laboratory) and other new members (2b, 2c) of this class of compounds. Alkynyliodonium compounds with R[DOUBLE BOND]alkyl react differently: instead of undergoing a 1,2-alkyl migration, the isocyanovinylidene intermediate is stabilized by insertion into the (alkyl)C[BOND]H bond.

      • equation image
    9. FAST NOESY Experiments—An Approach for Fast Structure Determination (pages 332–334)

      Dr. Matthias Köck and Prof. Dr. Christian Griesinger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403321

      NOESY spectra can be acquired five to ten times faster with the procedure described here. The reliability of the internuclear distances obtained from these spectra does not suffer. In addition to recording the FAST NOESY spectra, only the relaxation times T1 of the protons must be determined.

    10. Small Molecules Stabilized in Inorganic Frameworks: NbI5 Monomers in the Novel Layered Compound Nb7S2I19 (pages 334–336)

      Prof. Dr. Gordon J. Miller and Dr. Jianhua Lin

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403341

      Thumbnail image of graphical abstract

      Nb3SI7 layers with a new structural modification and the first-ever observed trigonalbipyramidal NbI5 monomers found in nearly hexagonal channels (see the structure on the right) characterize the title compound. According to physical measurements and structural calculations, these two components, which are unstable alone, are held together primarily by van der Waals and other dispersion forces.

    11. Enzymatic Hydrolysis of Hydrophilic Diethyleneglycol and Polyethyleneglycol Esters of Peptides and Glycopeptides by Lipases (pages 336–339)

      Prof. Dr. Horst Kunz, Dipl.-Ing. Danuta Kowalczyk, Dipl.-Chem. Peter Braun and Dr. Günther Braum

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403361

      New potentials not only in peptide synthesis are opened up by esters of diethyleneglycol monomethyl ether (MEE esters). Surprisingly, these esters can be hydrolyzed by lipases in neutral media. It was previously assumed that lipases cleave only esters that have both hydrophobic and polar regions, like the natural lipase substrates. During the ester hydrolysis, peptide linkages and common protective groups in peptide and carbohydrate chemistry remain intact. Remarkably, lipases in neutral medium can be used not only for MEE esters but also for polyethyleneglycol esters.

    12. Progress toward an Antibody Glycosidase (pages 339–341)

      Dr. Jaehoon Yu, Linda C. Hsieh, Dr. Lynn Kochersperger, Shirlee Yonkovich, James C. Stephans, Dr. Mark A. Gallop and Prof. Peter G. Schultz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403391

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      The piperidine-based hapten 1 generates monoclonal antibodies that catalyze the hydrolysis of substrate 2 at pH5.5 (kcal = 0.904 h−1, KM = 324 μM). Hapten 1 is a competitive inhibitor of the antibody-catalyzed reaction. These results are significant for the development of antibodies for the sequence-specific hydrolysis of oligosaccharides.

    13. Incorporation of L-[Methyl-2H3]methionine and 2-[Hydroxy-18O]hydroxyethylphosphonic Acid into Fosfomycin in Streptomyces fradiae—An Unusual Methyl Transfer (pages 341–342)

      Dr. Friedrich Hammerschmidt

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403411

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      A novel “methylation” takes place in the biosynthesis of the antibiotic fosfomycin: apparently a methyl group from L-methionine adds to phosphonoacetaldehyde (1) as “CHmath image” to provide (S)-2-hydroxypropylphosphonic acid (2). In contrast, (S)-adenosylmethionine transfers formally CHmath image in a different manner.

    14. Selective Measurement of the Time-Dependence of Transient Overhauser Effects in Magnetic Resonance: Applications to Oligonucleotides (pages 343–346)

      Sébastien J. F. Vincent, Catherine Zwahlen and Prof. Dr. Geoffrey Bodenhausen

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403431

      The analysis of cross- and diagonal-peak intensities is much faster with the one-dimensional NMR experiments described here than with two-dimensional NOESY. This accelerates the comparison of predictions from molecular dynamics calculations with experimental observations, as demonstrated by the example of cytosine-9 in duplex d(CGCGAATTCGCG)2.

    15. Fast Amide Cleavage under Mild Conditions: An Evolutionary Approach to Bioorganic Catalysis (pages 346–348)

      Prof. Fredric M. Menger and Dr. Zheng X. Fei

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403461

      The noncovalent aggregation of hexadecanoate in aqueous phosphate buffer with 3% acetonitrile gives rise to “catalytic clumps” that catalyze the hydrolysis of the amide group in 1. Amide cleavage is achieved with 108-fold acceleration with catalyst concentrations of 10−5M at pH 7–8. These extremely simple catalysts, whose activity equals or exceeds that of catalytic antibodies, were found by rapid screening of hundreds of organic “clumps”.

      • equation image
    16. Conformational Effects on the Redox Potentials of Tetraarylporphyrins Halogenated at the β-Pyrrole Positions (pages 348–350)

      Philippe Ochsenbein, Khadija Ayougou, Dr. Dominique Mandon, Prof. Dr. Jean Fischer, Prof. Dr. Raymond Weiss, Rachel N. Austin, Dr. Karupiah Jayaraj, Prof. Dr. Avram Gold, Prof. Dr. James Terner and Dr. Jack Fajer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403481

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      Despite four additional electron-withdrawing substituents, the octahalogenated porphyrins 2 are more easily oxidized than their tetra-halogenated counterparts 1. This apparent paradox can be explained by the structures of the molecules: porphyrins 2 are almost planar, whereas in 1 steric interactions are minimized by a saddle conformation, which makes these porphyrins easier to oxidize.

    17. The Effect of Chiral Bilayers: Wax Tubes Made of (S)-Nonacosan-10-ol (pages 350–351)

      Prof. Dr. Jürgen-Hinrich Fuhrhop, Thomas Bedurke, Airan Hahn, Prof. Dr. Siegfried Grund, Jürgen Gatzmann and Prof. Dr. Markus Riederer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403501

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      Unsymmetrical molecular interactions cause curvature in the double layers (depicted below) that arise from the crystallization from CHCl3 of the title enantiomer prepared by allylboration. Platelets without curvature are formed from the corresponding racemate. The curvature of these naturally occurring tubes thus depends on the chirality of the building blocks. Furthermore, the only piece of evidence for the chirality of the natural compounds comes from the curvature of its bilayer crystals.

    18. The Biosynthesis of Nitro Compounds: The Enzymatic Oxidation to Pyrrolnitrin of Its Amino-Substituted Precursor (page 352)

      Dipl.-Biol. Sabine Kirner and Priv.-Doz. Dr. Karl-Heinz van Pée

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403521

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      The enzymatic reaction aryl[BOND]NH2[RIGHTWARDS ARROW]aryl[BOND]NO2, the nonenzymatic counterpart of which requires drastic conditions, was previously hardly studied. Now a chloroperoxidase (CPO[BOND]P) isolated from the bacterial species Pseudomonas has been found to catalyze not only halogenations in vitro, but also the oxidation of the precursor 1 to 2.

    19. Phosphindolyl Anions by Elimination from 1-Phosphoallyllithium Complexes–η5 and η3 Coordination of a Phospholyl Fragment (pages 353–354)

      Prof. Dr. Edgar Niecke, Dr. Martin Nieger and Peter Wenderoth

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403531

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      A phosphindolyllithium complex or a lithium salt with a phosphindolyl anion? Both the ease of the synthesis and the structure of compounds 1 are surprising: the unit cell of crystalline 1 b contains two independent molecules in which lithium is coordinated in an η5 fashion in one and an η3 fashion in the other—this indicates the transition from the complex to the anion.

    20. Synthesis of Benzylated Cycloisomaltotri- and -hexaoside (pages 354–356)

      Dr. Stéphan Houdier and Prof. Dr. Philippe J. A. Vottéro

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403541

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      The first benzylated 1,6 analogue (1) of natural α-cyclodextrin was obtained as a side product in the I+ -mediated reaction of a pentenyl isomaltotrioside. The main product was the expected trimer.

    21. Synthesis and Structure of the Magnesium Imide [(thf)MgNPh]6 (pages 356–357)

      Tony Hascall, Dr. Karin Ruhlandt-Senge and Prof. Philip P. Power

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199403561

      Thumbnail image of graphical abstract

      A hexagonal prism, in which the two parallel six-membered rings of alternating Mg and N atoms are almost planar, forms the molecular framework of the title compound (Ph and THF substituents are represented by ipso-C and O atoms, respectively, in the picture shown on the right). This compound, which can be readily synthesized from Et2Mg and H2NPh in ether, is the first well-characterized magnesium imide.

  5. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    7. New Books
  6. New Books

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    7. New Books

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