Angewandte Chemie International Edition in English

Cover image for Vol. 27 Issue 6

June 1988

Volume 27, Issue 6

Pages 759–864

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 6/1988)

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198807591

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      The cover shows propella[34]prismane. It may be described as a cubane, four edges of which are bridged by trimethylene groups. It was prepared in only three steps from cyclodeca-1,6-diyne via a metal- and light-induced double dimerization. This synthesis is a prime example of how complicated molecules may be synthesized by including metals in the reaction sequence. Further details on propella[34]prismane and its thermal and photochemical rearrangement products are reported by R. Gleiter and M. Karcher on p. 840. (The cover picture was drawn using the MOLEK-9000 program (ISKA-Bensheim) on an HP-9000-350 computer.)

  1. Reviews

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. Tellurium-Rich Tellurides (pages 759–772)

      Prof. Dr. Peter Böttcher

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198807593

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      Tellurium-rich tellurides represent a link between Zintl phases, on the one hand, and molecular compounds of nonmetals on the other. Without exception, they are characterized by directed Te--Te bonds, whereby the Te atoms can be involved in more than two bonds. As shown by the example on the right, a frequently occurring structural motif is the TeTe4 unit (hatched). The fact that some of these tellurides also exhibit interesting physical properties (semiconductivity, low-dimensional electron transport, spin-glass behavior) makes a knowledge of their structures even more important.

    2. Isoleucyl-tRNA Synthetase: An Enzyme with Several Catalytic Cycles Displaying Variation in Specificity and Energy Consumption (pages 773–788)

      Dr. Wolfgang Freist

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198807731

      The aminoacyl-tRNA synthetases must differentiate between the various amino acids in the cytosol and couple them with their corresponding tRNAs. Owing to their great similarity, amino acids such as isoleucine and valine make special demands on the enzyme. The isoleucyl-tRNA synthetases (e.g., from yeast and E. coli) use proofreading mechanisms, which make them unique among other important enzymes of metabolism. Even small variations in the reaction conditions can cause conformational changes in these proteins and therefore influence the catalytic cycle. The specificity may thereby be widely varied.

    3. Photochemical Reactions of Ligands in Transition-Metal Complexes (pages 789–796)

      Dr. Anatoli L. Poznyak and Dr. Valeri I. Pavlovski

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198807891

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      Elimination of a ligand fragment and coordination of the remaining portion of the ligand to the metal center or appreciable rearrangement of the coordinated ligand and change in the mode of coordination--these are the two kinds of photochemical reactions that coordinated ligands may undergo. Most such reactions are induced by irradiation at the wavelength of the charge-transfer bands. An example of the first type of reaction is provided by Equation (a).

    4. Cyclobutanones and Cyclobutenones in Nature and in Synthesis [New Synthetic Methods(71)] (pages 797–827)

      Dr. Daniel Belluš and Dr. Beat Ernst

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198807971

      At first academic curiosities, four-membered ring compounds have emerged as excellent tools of organic synthesis during the past few decades. Substituted cyclobutanones and cyclobutenones are among the most accessible cyclobutane derivatives. Their chemical reactivity differs markedly from that of larger cyclic ketones; a major reason is the high ring strain of about 25 kcal mol-1. A detailed knowledge of the influence of this ring strain on the regio-, chemo-, and stereoselective transformations of four-membered ring ketones is of special value.

  2. Communications

    1. Top of page
    2. Reviews
    3. Communications
    4. Book Reviews
    1. (Mesityl)2Ge(fluorenylidene)–Stabilization of a Ge–C Double Bond by Charge Transfer into an Aromatic System (pages 828–829)

      Mohamed Lazraq, Dr. Jean Escudié, Dr. Claude Couret, Prof. Dr. Jacques Satgé, Prof. Dr. Martin Dräger and Dr. Ralph Dammel

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808281

      Not only steric shielding but also resonance with a delocalized π-electron system can help to stabilize nonclassical multiple bonds. Thus, despite high steric demands, 15 C atoms and the Ge atom of the title compound 1 lie nearly in the same plane. The experimental finding is in agreement with the result of a MNDO calculation.

    2. Distorted Triple-Diamond Structure of 3,3-Bis(carboxymethyl)glutaric Acid (“Methanetetraacetic Acid”) (pages 829–833)

      Prof. Dr. Otto Ermer and Andreas Eling

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808291

      The construction of interpenetrating networks is the fascinating possibility of-fered by tetracarboxylic acids containing tetrahedrally directed carboxyl groups. In the crystal they can form concatenated, diamondoid networks held together by pairs of hydrogen bonds. The cavities are filled owing to the interpenetration of several such networks. In the title compound C(CH2COOH)4 three translationally equivalent, tetragonally elongated diamondoid networks intermesh in a unique fashion. This kind of molecular architecture is a candidate for host structures in solid-state inclusion compounds. In addition, these structures are models for novel substances exhibiting unusual properties (diamondoid polymers, ferroelectric compounds).

    3. Mono- and Dinuclear Nickel(0) Complexes of Butadiyne (pages 833–835)

      Dipl.-Chem. Werner Bonrath, Dr. Klaus R. Pörschke, Prof. Dr. Günther Wilke, Dr. Klaus Angermund and Prof. Dr. Carl Krüger

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808331

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      The nickel(0) complex 1 containing the extremely easily polymerizable and explosive ligand butadiyne is crystalline and stable at room temperature under inert gas. Complex 1 and the analogous mononuclear complex can be interconverted. Their synthesis opens up new approaches to the commercial use of butadiyne, which is a byproduct of acetylene production (n = 2,3).

    4. Synthesis and Crystal Structure of a Chiral C3-Symmetric Monophosphane (pages 835–837)

      Dr. Carsten Bolm, Dr. William M. Davis, Dr. Ronald L. Halterman and Prof. Dr. K. Barry Sharpless

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808351

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      The C3-symmetric compounds 1 (R = H, tBu) are chiral phosphanes without a stereogenic C atom. A mutarotational energy of 11.8 kcal mol-1 was determined for the benzylphosphonium bromide of 1, R = H, by 1H-NMR spectroscopy. Resolution of the enantiomers was not achieved. Optically active C3-symmetric phosphane ligands are expected to exhibit good chiralitytransfer properties in transition-metal-catalyzed reactions.

    5. Formation of the Diphosphatricyclo[,5]pentane Ring System via Phosphaalkyne Dimerization and Carbon Monoxide Incorporation (pages 837–838)

      Dr. Andrew R. Barron, Prof. Dr. Alan H. Cowley, Stephen W. Hall and Dr. Christine M. Nunn

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808371

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      A new heteropolycyclic skeleton is present in the title compound 1, which was prepared from [Cp2Ti(CO)2] and tBuC[TRIPLE BOND]P by heating the reactants for several hours. It is remarkable that 1 does not remain bonded to the Ti complex. The X-ray structure analysis shows that the PP bond has slight multiplebond character.

    6. Addition of a Distannene to a Phosphaalkyne. Formation of a Phosphadistannacyclobutene (pages 838–839)

      Prof. Dr. Alan H. Cowley, Stephen W. Hall, Dr. Christine M. Nunn and Dr. John M. Power

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808381

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      A PSn2C ring containing a PC double bond is formed in the title reaction. Compound 1 is the first phosphadistannacyclobutene. The alternative formation via successive addition of two R2Sn units, formed in the equilibrium R2Sn = SnR2⇄2R2Sn, is unlikely, since an intermediate containing a PSnC ring could not be detected.

    7. Acetylene Polymerization with Ylide–Nickel Catalysts (pages 839–840)

      Dr. K. Alexander Ostoja Starzewski and Dr. Josef Witte

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808391

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      The bis(ylide)nickel complexes 1 catalyze acetylene polymerization. With respect to structure/activity relations, these one-component catalysts reveal similarities between acetylene and ethene polymerization. The activity of this catalyst system exceeds that of all other acetylen polymerization catalysts based on Ni. With 1a in dimethyl sulfoxide at 60 °C and 1 bar, it was possible to convert 500 moles of acetylene per mole of nickel.

    8. Synthesis and Properties of a Bridged syn-Tricyclo[,5]octa-3,7-diene: Formation of Propella[34]prismane (pages 840–841)

      Prof. Dr. Rolf Gleiter and Dr. Michael Karcher

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808401

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      How bridging can markedly change the reactivity of a compound is demonstrated by the tricyclo[]octadiene derivative 1. Its thermal and photochemical behavior is completely different from that of the parent compound. Upon warming, 1 undergoes a degenerate Cope rearrangement and, upon irradiation, the fourfold-bridged cubane 2 (“propella[34]prismane”) and its isomer 3 are formed.

    9. 1,3,4,6-Tetraamino-2,5-diazapentalenes: Delocalized Antiaromatic Compounds (pages 842–845)

      Dipl.-Chem. Fritz Closs, Prof. Dr. Rudolf Gompper, Prof. Dr. Heinrich Nöth and Dr. Hans-Ulrich Wagner

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808421

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      Tetradonor-substituted 2,5-diazapentalenes like 1 have been synthesized for the first time via a simple route. These crystalline, colored compounds exhibit high basicity; they can be oxidized to the radical cations and to the dications and reduced to the radical anions and to the dianions (multistep reversible redox systems). The double bonds in the tetraaminodiazapentalenes are delocalized, even though the systems contain eight π electrons.

    10. Formation of Difluoroethyne as a Ligand by Coupling of Two Fluoromethylidyne Ligands (pages 845–846)

      Priv.-Doz. Dr. Dieter Lentz and Dipl.-Chem. Heike Michael

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808451

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      C2F2, which is extremely unstable as a free molecule, was formed in a straightforward cluster expansion reaction. The closo cluster [Fe3(CO)93-CF)2] reacts with [Cp*Co(CO)2] to give the octahedral closo cluster [Cp*CoFe3(CO)942-FC[TRIPLE BOND]CF)], the framework of which is shown on the right. The C2F2 ligand is bent, so that the coordinated difluoroethyne may be viewed as an integral component of the closo cluster.

    11. X-Ray Structure Investigation of 2,2-Diphenyl-1-(phenylsulfonyl)cyclopropyllithium–Dimethoxyethane (2/3): A Sulfonyl “Carbanion” Having an α-C Atom with a Tetrahedral Configuration (pages 846–847)

      Dipl.-Chem. Werner Hollstein, Dr. Klaus Harms, Michael Marsch and Prof. Dr. Gernot Boche

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808461

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      The stabilization of a neighboring negative charge by a sulfonyl group is also possible when the α-C atom---as in 1---is not planar but rather tetrahedral in configuration. This finding indicates that a delocalization (pπ-dπ interaction) as in ester enolates and nitronates does not play a significant role in the stabilization of such sulfonyl “carbanions.” Much more important is an n-σ* interaction, as has also been shown from quantum-mechanical calculations.

    12. A Simple Access to 2-Substituted 3,3,3-Trifluoroalanine Derivatives (pages 848–849)

      Prof. Dr. Klaus Burger, Dipl.-Chem. Klaus Geith and Dipl.-Chem. Karl Gaa

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808481

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      2-Substituted 3,3,3-trifluoroalanines, which have been little investigated, are highly selective, irreversible enzyme inhibitors. The new compounds 2 and 3 also belong to this class of molecules. The synthesis described here starts from oxazole 1, which is treated with an alkenyl or alkynyl alcohol, respectively, in the presence of KOH. Both 2 and 3 are capable of undergoing further functionalization. R1-R3 are, for example, CH3, C2H5, C2H3, H.

    13. Equipotential Surfaces in Periodic Charge Distributions (pages 849–850)

      Prof. Alan Lindsay Mackay

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808491

      A microcomputer is sufficient to calculate and display approximate equipotential surfaces in ionic crystals. It is necessary and, as could be shown, justified to consider only a few Fourier terms. Equipotential surfaces are helpful, for example, in understanding the principles of construction of ionic crystals and the role of electrostatic effects in protein structure.

    14. Synthesis and Structure of [CIV(OSiMe3)N2PPh2]2, the First Cyclodimetallaphosphazene–an Eight-Membered Planar Unsaturated Heterocycle (pages 850–851)

      Dr. Michael Witt, Prof. Dr. Herberi W. Roesky, Dr. Mathias Noltemeyer and Prof. George M. Sheldrick

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808501

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      The heterocyclic moiety of 2 is an 8π-electron system, yet planar. The divanadacyclophosphazene 2 is a brick-red compound formed in 80% yield upon reaction of VOCl3 with 1. The heterocycle 2 is thermally very stable, but extremely sensitive to moisture.

    15. The First “Adamantoid” Alkaline Earth Metal Chelate Complex: Synthesis, Structure, and Reactivity (pages 851–853)

      Prof. Dr. Rolf W. Saalfrank, Dipl.-Chem. Armin Stark, Dr. Karl Peters and Prof. Dr. Hans Georg von Schnering

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808511

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      An Mg4 tetrahedron constitutes the center of the chelate complex anion of 1, which is obtained in 85% yield from diethyl malonate, methylmagnesium iodide, and oxalyl chloride (1:1:0.25). Acid hydrolysis of 1 affords the free chelate ligand, which is an extremely interesting synthetic building block.

    16. Preparative UV-Laser Photochemistry: A Biscarbene Intermediate in the Synthesis of a 5,6-Dihydrodibenzo[a,e]cyclooctene Containing a trans-Double Bond (pages 853–855)

      Dr. Klaus Hannemann and Prof. Dr. Jakob Wirz

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808531

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      An unusual route to a very unusual compound--this is an apt description of the synthesis of 3 via 2 by preparative laser photolysis of 1 (49% yield). In the conventional photolysis of 1,3 was not observed; the main products of these reactions are indenoindenes.

    17. Reduction of Epoxides, α,β-Unsaturated Aldehydes, and Vicinal Diketones with “Reactive Titanocene” (pages 855–856)

      Dr. Rainer Schobert

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808551

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      The deoxygenation of epoxides 2 to give the alkenes 3 can be carried out with “reactive titanocene” stereoselectively in high yield. The reagent is generated in situ from 1. The other two title compounds allow access to bis(allyl alcohols) or bis(allyl) ethers and to acyloins, ketones, or vinylene carbonates.

    18. A Novel Tetranuclear Copper(I) Cluster with Alternate Bridging Halide and Triazolopyrimidine Ligands (pages 856–858)

      Dr. Jaap G. Haasnoot, T. Loek F. Favre, Dr. Winfried Hinrichs and Prof. Dr. Jan Reedijk

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808561

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      The diverse coordination properties of (de)azapurines--the study of which is of great importance for bioinorganic chemistry--are revealed once again by a new type of copper(I) cluster. In 1, the ligand dmpt is bonded, for the first time, through N3 and N4. The ligands thereby form double layers. The anions are sandwiched between the double layers. This unique complex is formed in a straightforward fashion from CuCl2·H2O and dmpt in hot ethanol.

    19. Synthesis of Peptides Containing (S)-α-Methylserine (pages 858–859)

      Dr. Eva Altmann, Karl-Heinz Altmann and Prof. Dr. Manfred Mutter

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808581

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      A side-chain protecting group was not necessary in carrying out the synthesis of a number of dipeptides containing as C-terminal amino acid the helix-inducing (S)-α-methylserine. Furthermore, (S)-α-methylserine can be converted into the derivative 1, bearing a side-chain protecting group.

    20. Oxidative Coupling of Racemic and of Optically Active 3,6-Di-tert-butylocta-1,4,7-triyne-3,6-diol (pages 859–860)

      Prof. Dr. Fumio Toda, Jyōji Okada and Koji Mori

      Version of Record online: 30 DEC 2003 | DOI: 10.1002/anie.198808591

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      An optically inactive cyclic dimer 1 and an optically active polymer 2 are the products of the two title reactions. This dramatic difference in reactive behavior is of great importance with regard to the formation of natural, optically active polymers.

  3. Book Reviews

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