Angewandte Chemie International Edition in English

Cover image for Vol. 33 Issue 6

March 31, 1994

Volume 33, Issue 6

Pages 591–697

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 6/1994)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199405891

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      The cover picture shows a section of the polyhedral representation of the structure of potassium zeolite L (K9L) (SiO4, AlO4 tetrahedra, potassium atoms as spheres, the colors of which distinguish the three different crystallographic positions). When K9-L is exposed to a defined amount of potassium vapor, neutron diffraction shows that potassium atoms are incorporated only at the partially occupied K(4) sites (green) that are arranged about the large one-dimensional channels of the zeolite framework. These atoms are ionized, and the electrons released remain primarily within these channels, to compensate for the excess positive charge on the K(4) positions. Investigations with ESR spectroscopy showed that if one electron is confined to a single channel, it would be delocalized over six to eight unit cells (a distance of 4.5 to 6.0 nm). P. A. Anderson, A. R. Armstrong, and P. P. Edwards report more on the controlled introduction of electrons in microporous solids on p. 641 ff.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Chiral Aziridines—Their Synthesis and Use in Stereoselective Transformations (pages 599–619)

      Dr. David Tanner

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199405991

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      Like epoxides, only more versatile—this paraphrase of the title of an article by K. B. Sharpless et al. characterizes chiral aziridines. The easily accessible, strained heterocycles 1 may serve as chiral substrates, auxiliaries, reagents, and ligands for the synthesis of enantiomerically pure compounds.

    2. Theoretical Definition of a Functional Group and the Molecular Orbital Paradigm (pages 620–631)

      Prof. Richard Frederick William Bader, Dr. Paul Lode Albert Popelier and Todd Alan Keith

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406201

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      Atoms in molecules can be defined by quantum mechanics. This statement and its validity for the chemist's functional group are demonstrated here. The groups calculated by quantum mechanics are characterized by the fact that they and their properties are as readily transferable as the empirically defined functional groups. Two pictorial representations of groups calculated in this way are shown on the right.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Opportunities for New Chemical Libraries: Unnatural Biopolymers and Diversomers (pages 633–636)

      Dr. Rob M. J. Liskamp

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406331

      The search for lead compounds may well be simplified by libraries of unnatural compounds, whose lead compounds may require less extensive modifications for the development of drug candidates than those derived from peptide and oligonucleotide libraries. An oligocarbamate library described by Cho et al. and a benzodiazepine library proposed by Hobbs DeWitt et al. should point the way to a large number of libraries.

    2. Construction of Carbon Frameworks with the Help of Ruthenium Complexes: 1,5-Cyclooctadiene as a Reagent in Transition Metal Catalyzed Reactions (pages 636–638)

      Prof. Dr. Holger Butenschön

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406361

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      Hitherto 1,5-cyclooctadiene (COD) was used almost exclusively as a ligand in transition metal complexes; however, Trost et al. have recently found a ruthenium-catalyzed reaction, in which COD functions as bis-homodiene and undergoes a cyclization with alkynes to form derivatives of the tricyclo-[, 5]dec-7-ene (1) in good yields. Thus, COD may now be considered as a synthetic building block.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. A Novel Open-Framework Cobalt Phosphate Containing a Tetrahedrally Coordinated Cobalt(II) Center: CoPO4 · 0.5 C2H10N2 (pages 639–640)

      Dr. Jiesheng Chen, Dr. Srinivasan Natarajan, Prof. Sir John Meurig Thomas, Dr. Richard H. Jones and Prof. Michael B. Hursthouse

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406391

      A network of alternating CoO4 and PO4 tetrahedra linked through corners is formed by the blue title compound. The CoII centers are exclusively in a tetrahedral environment, as the compound's color indicates. The channels, whose pore openings (with respect to Co and P atoms only) are regular octahedra in one direction, but compressed eight-membered rings in the others, lie parallel to the crystallographic axes.

    2. Ionization and Delocalization in Potassium Zeolite L: A Combined Neutron Diffraction and Electron Spin Resonance Study (pages 641–643)

      Dr. Paul A. Anderson, Dr. A. Robert Armstrong and Prof. Dr. Peter P. Edwards

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406411

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      In the reaction of dehydrated zeolite L with potassium vapor the guest metal atoms are spontaneously ionized and the resulting electrons delocalized among potassium cations that line the one-dimensional channels of the zeolite host (see structure on the right). This phenomenon points out a possible approach to compounds containing ultrafine, conducting wires.

    3. Mapping the Electrostatic Potential of Muscarinic and Nicotinic Agonists with Artificial Neural Networks (pages 643–646)

      Prof. Dr. Johann Gasteiger and Dr. Xinzhi Li

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406431

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      Distinct similarities can be detected with artificial neural networks between molecules that bind to the muscarinic receptors (e.g. 1 and 2) and between molecules that bind to nicotinic receptors (e.g. 3 and 4). Furthermore such networks highlight differences between molecules that bind at these two different receptors.

    4. The Equilibrium Distribution of Semivolatile Organochloro Compounds between Atmosphere and Surface Water in the Atlantic Ocean (pages 646–649)

      Dipl.-Chem. Jörn Schreitmüller and Prof. Dr. Karlheinz Ballschmiter

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406461

      The South Atlantic Ocean is of global importance as sink and source for anthropogenic pollutants. Here the distribution of polychlorinated cyclic hydrocarbons between surface water and the atmosphere in this region is shown to fit a classical thermodynamic model of a temperature-dependent equilibrium—a new example of the concept of a global environmental chemistry.

    5. Zigzag Channels in the Structure of Sebaconitrile/Urea (pages 649–652)

      Prof. Mark D. Hollingsworth, Dr. Bernard D. Santarsiero and Dr. Kenneth D. M. Harris

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406491

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      What happens when the guest does not fit the host? The guest is not accommodated … or the host modifies its structure! In the urea inclusion compound with sebaconitrile (structure shown on the right), the adjustment of the host structure to the requirements of the guest, which is firmly bound by hydrogen bonds, results in an unconventional crystal form. Comparison with the structure of the (D4)urea inclusion compound, which crystallizes in the normal form, indicate the reasons for this structural change.

    6. A Novel Route to Diastereomerically Pure (E)-Alkene Dipeptide Isosteres from β-Aziridinyl-α,β-enoates by Treatment with Organocopper Reagents (pages 652–654)

      Prof. Dr. Toshiro Ibuka, Kazuo Nakai, Hiromu Habashita, Yuka Hotta, Prof. Dr. Nobutaka Fujii, Prof. Dr. Tooru Taga, Norio Mimura, Dr. Yoshihisa Miwa and Prof. Dr. Yoshinori Yamamoto

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406521

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      Why do enoates 1 and 2 give the same product 3 in their reaction with organocopper reagents? The absolute configuration at the alkylated α position and the (E) configuration of the biologically important N-protected dipeptide isostere 3 reflect the preferred conformation of substrates 1 and 2, which in turn is controlled by allylic 1,3 strain.

    7. Synthesis and Third-Order Nonlinear Optical Properties of a Conjugated Porphyrin Polymer (pages 655–657)

      Dr. Harry L. Anderson, Simon J. Martin and Dr. Donal D. C. Bradley

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406551

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      The π–π* absorption edge (Q band) of the soluble porphyrin polymer 1 lies in the IR region and is unusually intense. Electroabsorption (Stark) spectra demonstrate that polymer 1 has an exceptionally large third-order nonlinear susceptibility.

    8. Hydroxylamine, Hydrazine, and Diazene as Unidentate Ligands in Osmium and Ruthenium Complexes (pages 657–659)

      Tan-Yun Cheng, Adrian Ponce, Prof. Gregory L. Hillhouse and Prof. Arnold L. Rheingold

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406571

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      The unidentate trans-HN[DOUBLE BOND]NH ligand in 1 (M = Os) is the most significant structural feature of this surprisingly stable compound. The positions of the two H atoms in the diazene were located and refined in the X-ray structural analysis. Compound 1 and the analogous Ru complex were prepared by the oxidation of the corresponding hydrazine complexes.

    9. Stable Germirane Derivatives (pages 659–661)

      Prof. Dr. Wataru Ando, Harunobu Ohgaki and Dr. Yoshio Kabe

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406591

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      Electron-rich and -poor olefins undergo addition reactions with germanediyl 1. Its reaction with hexatriene 2 gives 3; with N-phenylmaleimide (4) the bicyclic germirane 5 is obtained. The two germirane products 3 and 5 were characterized by X-ray structure analysis. R = (Me3Si)2CH.

    10. Electron-Reservoir Complexes [FeICp(arene)] as Selective Initiators for a Novel Electron Transfer Chain Catalyzed Reaction: General Synthesis of Fulvalene-Bridged Homo- and Heterodinuclear Zwitterions (pages 661–663)

      Dr. David S. Brown, Dr. Marie-Hélène Delville-Desbois, Priv.-Doz. Roland Boese, Prof. K. Peter C. Vollhardt and Prof. Didier Astruc

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406611

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      Within only five minutes at 20°C bimetallic fulvalene complexes 1 undergo intramolecular disproportionation in the presence of PMe3 or P(OMe)3 when electron-reservoir complexes of the type [FeICp(arene)] serve as catalysts. MI = Mo, W, Fe, Ru; M2 = Mo, W; n = 2, 3; m = 3; arene = C6H6, C6Me6. The heterodinuclear complexes react with regioselectivity.

    11. 3-Phosphonio-1,2-diphosphaindenides and the Electrophilic Substitution of C-Phenyl-Substituted Ylides (pages 663–665)

      Dipl.-Chem. Georg Jochem, Prof. Dr. Alfred Schmidpeter, Dr. Martina Thomann and Prof. Dr. Heinrich Nöth

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406631

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      Substitution in the ortho or para position of a C-phenyl ring in the reaction of Ph3P = CPh2 with chlorodiphenylphosphane leads to compounds 1 and 2, respectively. The reaction of C-dihalophosphino-C-phenyl ylides Ph3P[DOUBLE BOND]C(PX2)Ph with PX3 (X = Cl, Br) proceeds by a presumably intramolecular ortho substitution and yields 1,2-dihalo-1,2-diphosphaindanes 3, which can be reduced to the title compounds 4.

    12. Chemistry within a Unimolecular Micelle Precursor: Boron Superclusters by Site- and Depth-Specific Transformations of Dendrimers (pages 666–668)

      Prof. George R. Newkome, John M. Keith, Dr. Gregory R. Baker, Gregory H. Escamilla and Dr. Charles N. Moorefield

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406661

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      The water-soluble dendrimer 1, functionalized at specific internal sites with twelve carborane units, and a dendrimer containing four carborane units in its first generation were generated from dendrimers containing twelve and four internal alkyne functions. This represents the first example of the modification of the interior of a dendrimer at a defined distance from its surface. Water-soluble forms of boron are important in cancer therapy and in catalysis. R = CH2OCH2C6H5, CH2OH, CH2OSO3H.

    13. 1(9)-Homocubene and 9-Homocubylidene: Theoretical Investigation of Structures, Energies, and Rearrangement Reactions (pages 668–670)

      Dipl.-Chem. Max C. Holthausen and Prof. Dr. Wolfram Koch

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406681

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      1(9)Homocubene (1) is not an olefin but a singlet diradical according to quantum chemical ab initio calculations. Compound 1 and its isomer 2 are very close in energy, which explains the unusual, reversible rearrangement 12, which proceeds by a C[BOND]C bond shift.

    14. Fairly Strong Ferromagnetic Interactions between Imino Nitroxide Ligands through a Diamagnetic CuI Ion in [CuI(im-mepy)2](PF6) (pages 670–671)

      Prof. Hiroki Oshio, Takashi Watanabe, Akihiro Ohto, Prof. Tasuku Ito and Prof. Umpei Nagashima

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406701

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      The orthogonal arrangement of the magnetic orbitals of the nitroxide ligands in 1 is the basis of the magnetic behavior of this complex. Temperature-dependent measurements of the magnetic susceptibility show that χmT gradually increases with decreasing temperature and reaches a plateau (0.96 emu mol−1) at 40 K; however, at temperatures below 20 K there is a sudden decrease. This behavior can be interpreted as a ferromagnetic interaction between the nitroxide ligands.

    15. Synthesis and Crystal Structure of a Monocarbene Complex of Copper (pages 672–673)

      Prof. Dr. Helgard G. Raubenheimer, Dr. Stephanie Cronje, Mr. Pierre J. Olivier, Dr. James G. Toerien and Prof. Dr. Petrus H. van Rooyen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406721

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      By alkylation of a thiazolyl cuprate (1), the neutral carbene copper complex 2 was synthesized. An X-ray structure analysis of 2 showed a Cu[BOND]C bond of 1.888(6) Å and an almost linear Cl-Cu-C unit (166.9(2)°).

    16. The Synthesis of Naturally Occurring ([BOND])-Calyculin A (pages 673–675)

      Dr. Norihiko Tánimoto, Dr. Samuel W. Gerritz, Dr. Akiyoshi Sawabe, Dr. Takeshi Noda, Sandra A. Filla and Prof. Satoru Masamune

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406731

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      Several intriguing transformations culminated in the first total synthesis of the title compound 1—the nonnatural ent-1 had been published previously—on coupling the fragments A, A′, B, and C. Crucial steps of the synthesis are the aldol reactions in the construction of fragment B, which solved the tricky problem of the stereoselective coupling of chiral fragments.

    17. Titanium Complexes with Tripodal Amido Ligands: Building Blocks for Stable Bimetallic Coordination Compounds Containing Highly Polar Metal–Metal Bonds (pages 676–678)

      Stefan Friedrich, Harald Memmler, Dr. Lutz H. Gade, Wan-Sheung Li and Prof. Mary McPartlin

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406761

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      Unsupported Ti[BOND]Fe, Ti[BOND]Ru, and Ti[BOND]Co bonds are found in the stable dinuclear compounds of type 1 (M = Fe, Ru, Co). These compounds were synthesized from the appropriate mononuclear titanium bromide complex and carbonyl metalates. The polydentate ligands on the early transition metal clearly provide the key to successful stabilization of the unsupported metal–metal bond.

    18. Direct Metal–Metal Bonds Between High and Low Valent Complex Fragments: The Reaction of Metal Bases with the Metal Acids [Re(NR)3]+ and [Mo(NR)2]2+ (pages 678–681)

      Dr. Jörg Sundermeyer, Dipl.-Chem. Diane Runge and Prof. John S. Field

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406781

      Shortened metal–metal bonds caused by electrostatic attraction within the dipolar (metalδ+ – metalδ−) structural unit were observed in the heterobi- and heterotrimetallic complexes of type 1 and 2. These complexes were synthesized from the imido complexes [(NtBu)3ReCl] or [(NtBu)2MoCl2] and the carbonyl metalates K[M]. [M] = CpMo(CO)3, CpW(CO)3, Mn(CO)5, CpFe(CO)2, Co(CO)4.

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    19. Tetrakis(hypersilyl)dithallium(Tl[BOND]Tl): A Divalent Thallium Compound (pages 681–683)

      Sonja Henkel, Dr. Karl Wilhelm Klinkhammer and Dr. Wolfgang Schwarz

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406811

      A Tl[BOND]Tl bond 291.4 pm in length is the prominent structural feature of the thallium(II) compound 1, the product of the reaction of RbSi(SiMe3)3 with TlN(SiMe3)2. The red compound 1, which is thermally unstable in solution, can be stored for longer periods in the solid state.

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    20. Asymmetric Synthesis of Highly Substituted Pyrrolidines by 1,3-Dipolar Cycloadditions of Azomethine Ylides with N-Acryloylproline Benzyl Ester (pages 683–685)

      Prof. Dr. Herbert Waldmann, Dipl.-Chem. Edwin Bläser, Prof. Dr. Martin Jansen and Dipl.-Chem. Hans-Peter Letschert

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406831

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      Azomethine ylides accessible from Schiff's bases of aliphatic and aromatic amino acid esters undergo asymmetric 1,3-dipolar cycloadditions with N-acryloyl-(S)-proline benzyl ester in THF at low temperatures. Satisfactory yields of highly substituted pyrrolidines of type 1 are obtained in excellent enantiomeric excesses. The corresponding 2,4-dicarboxylic acids can be readily prepared from these pyrrolidines. Bzl = benzyl.

    21. Vanadium(II)- and Niobium(III)-Induced, Diastereoselective Pinacol Coupling of Peptide Aldehydes to C2-Symmetrical HIV-Protease Inhibitors (pages 685–687)

      Dr. Bernhard Kammermeier, Dr. Gerhard Beck, Priv.-Doz. Dr. Heiner Jendralla and Dr. Detlev Jacobi

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406851

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      Potent inhibitors of HIV-protease such as 1 can be produced on a kilogram scale by diastereoselective, reductive dimerization of homochiral peptide aldehydes. This is made possible by the use of niobium catalysts or vanadium catalysts generated in situ in the crucial reaction step. aryl = 1-naphthyl.

    22. A Sugar Amino Acid as a Novel Peptidomimetic (pages 687–689)

      Dipl.-Ing. Erich Graf von Roedern and Prof. Dr. Horst Kessler

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406871

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      A sugar amino acid in the peptide backbone marks a novel class of unnatural peptide building blocks with interesting properties. By incorporation of the readily accessible sugar amino acid into peptides, the structure and pharmacokinetics can be influenced directly. This is demonstrated for cyclic and linear somatostatin (1) and enkephalin analogues.

    23. Discrete M6N Octahedra in the Subnitrides Na16 Ba6N and Ag16Ca6N: A Reconsideration of the Ag8Ca3 Structure Type (pages 689–691)

      G. Jeffrey Snyder and Prof. Dr. Arndt Simon

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406891

      The future of subnitride chemistry appears promising: M6 octahedra with a central N atom have been detected in the new compound Na16Ba6N and in the compound hitherto described as “Ag8Ca3”; the latter is actually the isotypic Ag16Ca6N (with 0.7% N)! In these compounds the M6N octahedra are embedded in a matrix of Na and Ag, respectively. Numerous phases with the Ag8Ca3 structure such as Ni6Si2M3 and Ni6Al2M3 (M = rare-earth metal) may likewise be stabilized by interstitial atoms.

    24. A Clathrate Hydrate of Nitric Oxide (pages 691–693)

      Dr. Andreas Hallbrucker

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406911

      A somewhat surprising structural type was determined by X-ray diffraction for the clathrate hydrate of NO: unlike CO, a molecule with very similar properties, NO forms a clathrate hydrate of structural type II, which hitherto had only been encountered for larger molecules (van der Waals radius > 5.8 Å) and nonpolar small molecules like N2 and O2. Thus, further study is required to establish the criteria that determine the structure type of clathrate hydrates.

    25. Rearrangement and Selective Transmetalation of Bis(pyridyl)methyllithium (pages 693–695)

      Dipl.-Chem. Heinz Gornitzka and Priv.-Doz. Dr. Dietmar Stalke

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199406931

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      The first structurally characterized sodium lithate 1 was obtained by selective transmetalation of [Li{(2-NC5H4)2CH}(thf)2] (2) with the superbase 2/NaOtBu. The exchange of only half an equivalent of Li ions in 2 is ascribed to the shape and the basicity of the bis(pyridyl)methyl ligand.

  4. Book Reviews

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