Angewandte Chemie International Edition in English

Cover image for Vol. 32 Issue 7

July 1993

Volume 32, Issue 7

Pages 923–1110

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 7/1993)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199309231

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      The cover picture shows a computer-generated ball-and-stick model of tetrakis(tri-tert-butylsilyl)-tetrahedro-tetrasilane, the first molecular silicon compound containing a Si4 tetrahedron (in magenta). After the Ge6 prismanes and Sib8 and Sn8 cubanes, this tetrasilatetrahedrane is another milestone in the synthesis of highly symmetric, strained polycycles exclusively constructed from the higher homologues of carbon. It reemphasizes that unusual molecular frameworks can be stabilized by bulky substituents. More on the synthesis, which has most probably been and still will be attempted in many research groups, and the properties of this compound is reported by N. Wiberg et al. on p. 1054 ff.

    2. Graphical Abstract (Angew. Chem. Int. Ed. Engl. 7/1993)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199309232

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Methods for the Synthesis of μ-Hydrocarbon Transition Metal Complexes without Metal–Metal Bonds (pages 923–949)

      Prof. Dr. Wolfgang Beck, Dr. Burkhard Niemer and Dipl.-Chem. Michael Wieser

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199309233

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      The most important types of reaction in organometallic chemistry are required in the synthesis of complexes containing hydrocarbon bridges, the subject of this review. Such complexes often have pleasing structures (see 1), but their significance extends beyond aesthetics. They are models of intermediates in the Fischer–Tropsch synthesis and of unsaturated hydrocarbons chemisorbed on metal surfaces (important in heterogeneous catalysis).

    2. The Role of Chemistry in the Development of Boron Neutron Capture Therapy of Cancer (pages 950–984)

      Prof. Dr. M. Frederick Hawthorne

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199309501

      10B deliberately placed in tumors is expected to revolutionize therapy for cancers, because its reaction with innocuous thermal neutrons forms the extremely energetic, short-lived product ions 4He2+ and 7Li3+, which kill cells only in their immediate vicinity. For maximum efficiency of this treatment, the boron isotope needs to be placed in the cell nucleus. Thus the boron-containing compound must reach the tumor, penetrate the cell membrane, and finally enter the cell nucleus, but may not simultaneously concentrate in healthy cells. In this review the progress of research in this multidisciplinary field is described from the chemical point of view.

    3. Classical and Nonclassical Methyleneboranes (pages 985–1009)

      Prof. Dr. Armin Berndt

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199309851

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      Electron deficiency at the dicoordinate boron atom in methyleneboranes can be alleviated in two ways: through “classical” π–π delocalization of adjacent, formally nonbonding electron pairs as in the amino(methylene) boranes 1, and through the “nonclassical” formation of multicenter bonds as illustrated in the structural formulas 2–4, the category that is the focus of this review. The structure and spectroscopic properties of methyleneboranes of this type resemble those of carbenium ions with strong σ–π delocalization (hyperconjugation, bridging) and transition metal complexes with strong agostic interactions.

    4. Syntheses of Polycyclic Natural Products Employing the Intramolecular Double Michael Reaction (pages 1010–1022)

      Prof. Masataka Ihara and Prof. Keiichiro Fukumoto

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310101

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      Compounds with two different α, β-unsaturated carbonyl groups can be converted regioselectively and stereoselectively in one step into polycyclic products with the title reaction, for which there are three experimental versions. These and related methods have proven exceptionally useful for the synthesis of alkaloids, steroids, terpenoids, and other natural products; the synthesis of the naturally occurring tylophorin enantiomer 2 from the chiral amide ester 1 illustrates their potential. (R* = phenylmenthyl).

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Successful X-Ray Structure Analysis of an Alkylidene Carbenoid—A Milestone in Carbenoid Research (pages 1023–1025)

      Prof. Dr. Adalbert Maercker

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310231

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      As temporary climax in carbenoid research, G. Boche et al. (see p.1032 ff) succeeded in performing an X-ray crystal analysis on 1-chloro-2,2-bis(chlorophenyl)-1-lithioethene (1). The structure confirms that the carbenoid C atom has rehybridized, as predicted by Köbrich. This result will certainly give impetus to investigations into the relationship between structure and reactivity in carbenoids.

    2. “Noncoordinating” Anions, II (pages 1025–1027)

      Prof. Dr. Konrad Seppelt

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310251

      An idealized state of a solution without cation–anion interactions can now be quite well approximated with weakly coordinating anions. Consequently, the prerequisites for the stabilization of coordinatively unsaturated cationic compounds that show unusual bonding or that are discussed as catalytically active species have been achieved. Strauss et al. have now established tellurate-containing anions such as 1–3, which show several advantages over the frequently used tetraarylborates and carborane anions. Cations such as [Ag(CO)2]+ and [Ag(CH2Cl2)3]+ can be isolated with them—in these two examples, for instance, the counterions are 1 and 3, respectively.

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    3. Biologically Active Linear Metabolites of Arachidonic Acid—The First Endogenous Ligand of the Cannabinoid Receptor (pages 1027–1029)

      Priv.-Doz. Dr. Wolf D. Lehmann and Dr. Gerhard Fürstenberger

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310271

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      Despite their simple construction the metabolites of arachidonic acid (1) are very important in the regulation of elementary biological processes such as the immune response and the receptor-mediated signal transduction in the nervous system. The first naturally occurring ligand of the cannabinoid receptor, which plays a role in the control of movement and the perception of pain, was isolated recently from porcine brain. This N-(2-hydroxyethyl)amide derivative of 1 binds to the receptor. Attempts to identify other arachidonic acid derivatives as ligands specific to this receptor have failed so far.

  3. Correspondences

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Concerning “An Evaluation of the Peer Review Process at Angewandte Chemie (page 1030)

      Dr. Paul F. Ross

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310301

      Is peer review working—that is, is it fair and does it identify significant papers? H. D. Daniel (Angew. Chem. Int. Ed. Engl. 1993, 32, 234) looked into this question in a study of the referee system of Angewandte Chemie that threw light on important aspects of this process. This further discussion between Ross and Daniel will therefore interest every reader.

    2. Reply: (pages 1030–1031)

      Priv.-Doz. Dr. Hans-Dieter Daniel

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310302

      Is peer review working—that is, is it fair and does it identify significant papers? H. D. Daniel (Angew. Chem. Int. Ed. Engl. 1993, 32, 234) looked into this question in a study of the referee system of Angewandte Chemie that threw light on important aspects of this process. This further discussion between Ross and Daniel will therefore interest every reader.

  4. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. 1-Chloro-2,2-bis(4-chlorophenyl)-1-lithioethene · TMEDA · 2THF: Structure of a Li[BOND]Cl Carbenoid (pages 1032–1033)

      Prof. Dr. Gernot Boche, Michael Marsch, Dipl.-Chem. Achim Müller and Dr. Klaus Harms

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310321

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      The Cl[BOND]Cl bond in the carbenoid 1 is about 12 pm longer than that in the compound containing a H atom in place of the Li substituent. This explains the facile reaction of carbenoids with the nucleophiles RLi. The X-ray crystal structure of 1 is consistent with 13C-NMR data, as well as with the stereochemistry of reactions of carbenoids with RLi or the Fritsch–Buttenberg–Wiechell rearrangement of vinyl carbenoids.

    2. Formation of Molecular Strands by Hydrogen Bonds at the Gas–Water Interface: Molecular Recognition and Quantitative Hydrolysis of Barbituric Acid Lipids (pages 1033–1036)

      Ramesh Ahuja, Pier-Lorenzo Caruso, Prof. Dr. Dietmar Möbius, Wolfgang Paulus, Prof. Dr. Helmut Ringsdorf and Gerald Wildburg

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310331

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      Reminiscent of an enzyme reaction is the proposed mechanism for the hydrolysis of the barbituric acid lipid 1, R = C16H33, when it forms a strand structure with 2,4,6-triaminopyrimidine (TAP) at the gas–water interface (2). The TAP-catalyzed hydrolysis at pH 6.5 is 14 times faster than the simple addition of 0H to the C[BOND]C double bond at pH 10.

    3. Hexakis(benzotriazolato)tetrakis(2,4-pentanedionato)pentacopper(II): A Model for Corrosion Inhibition (pages 1036–1038)

      Jane Handley, Dr. David Collison, Prof. C. David Garner, Dr. Madeleine Helliwell, Dr. Robert Docherty, Dr. John R. Lawson and Dr. Peter A. Tasker

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310361

      Each benzotriazolato (bta) ligand is bound to three copper(II) ions in the pentanuclear title complex. The known copper corrosion inhibitor, Hbta, might bind similarly to two metal atoms on the surface to be protected and one metal atom of the underlying layer. Results of molecular modeling studies suggest that the optimal interaction of bta with the surfaces of Cu2O and CuO occurs for an orientation perpendicular to the (110) surface.

    4. Why is Porphobilinogen the Biological Substrate for the Formation of Porphyrins? Calculations on the Conformation of Acyclic Tetrapyrroles and the Acid-Catalyzed Cyclization of Hydroxymethylpyrroles (pages 1038–1040)

      Prof. Dr. Lutz F. Tietze and Dr. Holger Geissler

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310381

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      The substitution patten of pyrrole is crucial for the ready conversion of porphobilinogen (1) into uroporphyrinogen III (6). This was indicated by model reactions with hydroxymethylpyrroles 2–5 and the results of semiempirical calculations. These calculations showed that the acyclic tetramer from 3, formulated as intermediate, has a preferred cyclic conformation as a result of 1,3-allylic strain; cyclization of this conformation should be quite facile. P=(CH2)2CO2H, A=CH2CO2H.

    5. Investigations in the Biosynthesis of the Pigments of Life: Calculations on the Formation of Uroporphyrinogen III from Hydroxymethylbilan and Description of a New Mechanism for the D-Ring Inversion (pages 1040–1042)

      Prof. Dr. Lutz F. Tietze and Dr. Holger Geissler

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310401

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      The direct formation of a spiro tetrapyrrole intermediate from hydroxymethylbilan (1) is energetically less favorable than the formation of a cationic σ complex in the first step of the cyclization to form uroporphyrinogen III (2) [Eq.(a)]. This was shown by calculations on model compounds (A, P = H or Me). The preferred mode of cyclization in the biosynthesis of 2, which proceeds by inversion of the D ring, can be formulated as an alternative mechanism and has stereoselective H abstraction and [1,5] sigmatropic shifts as key steps. P = (CH2)2CO2H, A = CH2CO2H.

    6. Highly Enantioselective Protonation of Thiol Ester Enolates (pages 1042–1044)

      Dr. Charles Fehr, Dr. Isabelle Stempf and José Galindo

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310421

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      Impressive enantiomer excesses of 99% were achieved in the protonation of thioester enolate 2, prepared from racemic 1, with the chiral proton sources (−)- and (+)-N-isopropylephedrine ((−)-3 and (+)-3). This large-scale procedure allows access to many enantiopure terpenoids.

    7. Enantioselective Addition of Aromatic Thiols to a Ketene (pages 1044–1046)

      Dr. Charles Fehr, Dr. Isabelle Stempf and José Galindo

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310441

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      High enantioselectivities, even though 95% of the protons come from an achiral source are obtained in the reactions of 1 with lithiated aromatic thiols like 2 in the presence of 5 mol% of the chiral catalyst 3. Ar = Ph, 2-naphthyl, p[BOND]ClC6H4.

    8. Alternating Ferro- and Antiferromagnetic Interactions in a Chainlike CuII Coordination Polymer (pages 1046–1048)

      Prof. Miguel Julve, Dr. Francesc Lloret, Prof. Juan Faus, Prof. Giovanni De Munno, Prof. Michel Verdaguer and Dr. Andrea Caneschi

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310461

      2,2′-Bipyrimidine (bpym) and hydroxo ligands alternately bridge the metal atoms in the complex 1, which exists as a chainlike coordination polymer. In this complex ferro- and antiferromagnetic interactions between the CuII centers alternate along the chain. In contrast, in the dimeric parent compound 2, which has a central hydroxo-bridged Cu2 unit and terminal bpym ligands, a strong ferromagnetic coupling occurs between the CuII centers.

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    9. Insertion of a Cp Unit into a Metal–Metal Bond: [Ru3(CO)10(C5H4)] and its PPh3 Derivative (pages 1048–1049)

      Dr. Daniel Heineke and Prof. Dr. Heinrich Vahrenkamp

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310481

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      The phosphorus ylide is cleaved in the reaction [Ru3(CO)12] with Ph3P[DOUBLE BOND]C5H4 in cyclohexane under reflux to give the novel compound 1 among the products. This is not a cyclopentadienylidene complex but rather a rutheniocyclopentadienylruthenium complex.

    10. Cs3AuO, the First Ternary Oxide with Anionic Gold (pages 1049–1050)

      Dipl.-Chem. Claus Feldmann and Prof. Dr. Martin Jansen

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310491

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      Interdiffusion of Cs2O and CsAu produced the first ternary oxide with anionic gold. A Au L3-XANES spectroscopic study showed that the anionic character of gold in Cs3AuO is even more pronounced than in CsAu. The structure of the new compound is depicted on the right.

    11. Cycloalkano-2H-pyrrole as a Stable Intermediate in the Conversion of β-Cycloalkenyl-α-azidoacrylates to Cycloalkano-1H pyrroles (pages 1051–1052)

      Dr. Claus Vogel, Dipl.-Chem. Bernd Schnippenkötter, Dipl.-Chem. Peter Bubenitschek and Prof. Dr. Peter G. Jones

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310511

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      A quantitative 1,5-electrocyclization takes place on thermolysis of the 2-vinylcycloalkenyl-α-azidoacrylate 1 to form the substituted cycloalkano-2H-pyrroles 2. Products of a reaction of vinyl azide or -nitrene with the unsaturated side chains were not observed.

    12. Catalytic Hydrogenation with Rhodium Complexes Containing dipamp-pyrphos Hybrid Ligands (pages 1052–1054)

      Prof. Dr. Ulrich Nagel and Thomas Krink

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310521

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      Very high enantiomeric excesses are more easily achieved when the catalyst contains a C2-symmetric ligand as a chiral inductor—this, however, does not hold for hydrogenation, catalyzed by rhodium complexes with 3,4-bis(phosphino)pyrrolidine ligands (e.g., 1). In the hydrogenation of (Z)-α-acetoamidocinnamic acid the results obtained with the asymmetric ligand are similar to those with the C2-symmetric ligands. Boc = tert-butoxycarbonyl.

    13. Tetrakis(tri-tert-butylsilyl)-tetrahedro-tetrasilane (tBu3Si)4Si4: The First Molecular Silicon Compound with a Si4 Tetrahedron (pages 1054–1056)

      Prof. Dr. Nils Wiberg, Dipl.-Chem. Christian M. M. Finger and Dr. Kurt Polborn

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310541

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      Yellow-orange tetrakis(supersilyl)-tetrahedro-tetrasilane (1), the first derivative of tetrahedro-tetrasilane Si4H4, is stable to heat, light, water, and air, and is not reduced by sodium at temperatures below 70°C, but reacts with oxidants like tetracyanoethylene and bromine. Compound 1 was obtained in 57% yield from reaction (a).

    14. (C6F5NGaMe)4 and (C6F5NInMe)4: The First Gallium–Nitrogen and Indium–Nitrogen Compounds with Cubane Structures (pages 1056–1058)

      Thomas Belgardt, Prof. Dr. Herbert W. Roesky, Dr. Mathias Noltemeyer and Hans-Georg Schmidt

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310561

      Ga4N4 and In4N4 cubes are the central structural units of the tetrameric iminometalanes 1 and 2, respectively. These are accessible from pentafluoroaniline and trimethylmetalane by methane elimination. Characteristic for these compounds is the increase in the distortion of the cubane framework with the increasing mass of the metal atom.

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    15. A New Route to Water-Soluble Phosphanes with para-Sulfonated Phenyl Substituents. Crystal Structure of P(C6H4[BOND]p[BOND]SO3K)3 · KCl · 0.5H2O (pages 1058–1059)

      Oliver Herd, Klaus Peter Langhans, Prof. Dr. Othmar Stelzer, Dr. Norbert Weferling and Prof. Dr. William S. Sheldrick

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310581

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      In the superbasic medium dimethylsulfoxide/KOH, potassium p-fluorobenzenesulfonate (1) can be treated with PH3 [Eq. (a)], or primary or secondary phosphanes to afford water-soluble phosphanes (3) containing sulfonated aromatic groups. The trianion [P(C6H4[BOND]p[BOND]SO3)3] in 2 · KCl · 0.5H2O is the first in this class of compounds that could be characterized by X-ray crystallography.

    16. [{(Et2O)2ClGa}Ga{GaCl2(Et2O)}3]: A Molecular Compound with a Tetrahedral Ga5 unit (pages 1059–1060)

      Dipl.-Chem. Dagmar Loos, Prof. Dr. Hansgeorg Schnöckel and Prof. Dr. Dieter Fenske

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310591

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      Oxidation states between O and H can be formally assigned to the five Ga atoms in the title compound 1 depending on the coordinating ligands. Each Ga atom has a tetrahedral coordination environment; the central atom is surrounded by the other four Ga atoms. Compound 1 crystallizes at −30°C from a cryochemically prepared solution of GaCl in toluene/diethyl ether.

    17. CeCl3-Mediated Addition of Grignard Reagents to 1,3-Diketones (pages 1061–1062)

      Prof. Dr. Giuseppe Bartoli, Dr. Enrico Marcantoni and Prof. Dr. Marino Petrini

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310611

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      β-Hydroxyketones 2 form in good yields by CeCl3-mediated addition of Grignard compounds to 1,3-diketones (1). In this chemoselective reaction, a complex from 1 and CeCl3 is presumably formed initially, which is then attacked at the sterically less hindered CO group by the R″MgX. (R″ = Me, Ph, nPr, H2C[DOUBLE BOND]CH, H2C[DOUBLE BOND]CHCH2).

    18. How N2 Might Be Activated by the FeMo-Cofactor in Nitrogenase (pages 1062–1065)

      Dr. Haibin Deng and Prof. Roald Hoffmann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310621

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      Most probably through a N2 complex similar to 1 is the proposal intimated in the title, which follows from extended-Hückel calculations on a model of the FeMo cofactor of the nitrogenase. Complex 1 shows two characteristics that make an activation of N2 for the reduction seem likely: a weakening of the N[BOND]N bond in comparison to that in free N2 and negative net charges at the N atoms. • = N, • = Fe (except extreme right: Mo), ˆ = S.

    19. Structural Evidence of the Aromaticity of Borepins: A Comparison of 1-Chloroborepin and Tricarbonyl(1-chloroborepin)molybdenum (pages 1065–1066)

      Prof. Dr. Arthur J. Ashe III, Dr. Jeff W. Kampf, Dr. Wolfram Klein and Roger Rousseau

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310651

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      A planar structure with C2v symmetry is a description of 1-chloroborepin 1, and is consistent with the presumption that 1 and probably also 1 H-borepin are aromatic compounds. The Mo(CO)3 complex was prepared from 1. Its structure was also determined, and it could be reduced to the stable complex 2.

    20. First Structure of a Mixed Organosodium/Lithium Alkoxide Compound: Model for a Superbase (pages 1066–1068)

      Dr. Sjoerd Harder and Prof. Dr. Andrew Streitwieser

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310661

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      Li[BOND]O interactions dominate the structure of 1, a molecule that contains the M[BOND]C and Li[BOND]O functionalities suspected to play a role in superbases involving RLi and R′OM (M = Na, K, Rb, Cs). Compound 1 forms a tmeda-coordinated tetramer with a central Li4O4 cube, and its O atoms have tetragonal-pyramidal coordination. This structure offers a possible explanation of the activation of organolithium compounds by alkali metal alkoxides.

    21. Rapid Carboalumination of Alkynes in the Presence of Water (pages 1068–1071)

      Prof. Dr. Peter Wipf and Sungtaek Lim

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310681

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      Within minutes at −23°C, alkenylalanes can be generated from terminal alkynes by Zr-catalyzed methyl- or ethylalumination, when stoichiometric amounts of water are added. Alkenes can be synthesized stereoselectively from the alkenylalanes. Reaction (a) is fast even at −70°C. The “water effect”, also observed in other reactions with organometallic compounds, is not yet understood.

    22. Stereochemistry of the C[BOND]S Bond Cleavage in 1-Phenylethyl Phenyl Sulfide Radical Cation: Evidence for a Unimolecular Pathway (pages 1071–1073)

      Prof. Dr. Enrico Baciocchi, Dr. Elisabetta Fasella, Dr. Osvaldo Lanzalunga and Dr. Mario Mattioli

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310711

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      Is the bond-cleavage mechanism uni- or bimolecular in the reaction (a)? The search for the answer involved the use of enantiomerically pure (R)-(+)-1, reaction conditions with or without base, and detailed product analyses. The experimental results are consistent with a unimolecular pathway, which initially leads to a contact radical cation pair and then to a solvent-separated radical cation pair.

    23. Structure and Reactivity of [HFe(CO)33[BOND]C3H5)] (pages 1073–1074)

      Terence M. Barnhart, Dr. James De Felippis and Prof. Robert J. McMahon

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310731

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      Postulated 30 years ago, the highly reactive intermediate1 of the Fe(CO)5-catalyzed alkene isomerization was observed for the first time in solution by NMR spectroscopy. The ability to generate and monitor such reactive species opens the way for detailed investigations of this important reaction.

    24. Organometallic Molecular Trees as Multielectron and Multiproton Reservoirs: CpFe+-Induced Nonaallylation of Mesitylene and Phase-Transfer Catalyzed Synthesis of a Redox-Active Nonairon Complex (pages 1075–1077)

      Dr. Françoise Moulines, Laurent Djakovitch, Dr. Bruno Gloaguen, Dr. Werner Thiel, Dr. Jean-Luc Fillaut, Dr. Marie-Hélène Delville, Prof. Didier Astruc and Prof. Dr. Roland Boese

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310751

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      A reservoir of 9 electrons and 27 protons, complex 1 has 8±1 quasi-equivalent redox centers. It is prepared from [CpFe(η6-mesitylene)]+ by nonaallylation of the three methyl substituents, demetalation, conversion into the corresponding nonaol, and phasetransfer-catalyzed reaction with [CpFe(FC6H4Me)].

    25. Novel Alkynylcopper(I) Complexes and Lithium Alkynyl Cuprates (pages 1077–1079)

      Dr. Falk Olbrich, Priv. Doz. Dr. Jürgen Kopf and Prof. Dr. Erwin Weiss

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310771

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      A tetrahedral tetraalkynylcuprate—a new structural unit for organocopper compounds—and a “crown” formed from three Li[PhC[TRIPLE BOND]CCuC[TRIPLE BOND]CPh] units (A) are contained in the first lithium alkynylcuprate 1. This complex was prepared from copper(I) bromide dimethylsulfide and LiC[TRIPLE BOND]CPh.

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    26. ansa-Metallocenes of Calcium and Strontium One-Pot Synthesis of Organometallic Complexes of the Heavier Alkaline Earth Metals (pages 1079–1081)

      Dipl.-Chem. Melanie Rieckhoff, Dr. Ursula Pieper, Dr. Dietmar Stalke and Priv. Doz. Dr. Frank T. Edelmann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310791

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      The reductive dimerization of 6,6-dialkylfulvenes by elemental calcium or strontium smoothly afforded the first ansa-metallocene derivatives of these metals. The bright red 1,4-diazadiene adduct 1 was characterized structurally.

    27. A Versatile and Efficient Synthesis of Annulated Cyclopentanes by Stereoselective [3 + 2] Cycloaddition of Allylsilanes and Cycloalkenyl Methyl Ketones (pages 1081–1083)

      Prof. Dr. Hans-Joachim Knölker, Dipl.-Chem. Norbert Foitzik, Dipl.-Chem. Regina Graf and Dr. Helmut Goesmann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310811

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      Useful precursors for cyclopentanoid natural products and for compounds with medium-sized rings can be prepared by the title reaction (a). This new annulation reaction is postulated to involve a cationic 1,2-silyl shift proceeding via a pentavalent silicon center.

    28. Structure and Reactivity of a Highly Twisted Amide (pages 1083–1085)

      Dr. Shinji Yamada

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310831

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      The largest twist angle of 74.3° at a C(O)[BOND]N bond known so far was detected in the amide 1 by IR, UV, and NMR spectroscopy, as well as X-ray crystallography. In 1 the thiazolidine ring is almost perpendicular to the CO group, which makes this compound extremely reactive.

    29. On the Mechanism of the TCPCHFB-Catalyzed Metathesis of 1,6-Enyne: Evidence for Alkylidenepalladium Intermediates (pages 1085–1087)

      Prof. Dr. Barry M. Trost and Dr. A. Stephen K. Hashmi

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310851

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      A metallacyclopentene–metallavinylcyclopropane rearrangement and a [4 + 2] cycloaddition of metalladienes are the novel reactions that take place during the reaction of vinyl-substituted enynes such as 1 (R = H, CH3, E′ = CO2CH3) with Pd catalysts such as 2 (R = CH2C3F7). The results support the intermediary of PdIV complexes 3 on the way to the products 4.

    30. Haematopodin, an Unusual Pyrroloquinoline Derivative Isolated from the Fungus Mycena haematopus, Agaricales (pages 1087–1089)

      Dipl.-Chem. Carsten Baumann, Dr. Martin Bröckelmann, Dr. Burkhard Fugmann, Dr. Bert Steffan, Prof. Dr. Wolfgang Steglich and Prof. Dr. William S. Sheldrick

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310871

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      First found in fungi, a pyrroloquinoline derivative, haemotopodin (1), arises in the decomposition of the native pigment of the sap. Compounds of this type, which also occur in marine sponges, can be synthesized by intramolecular cyclization of 6,7-dihydroxy-tryptamines—a potential model for their biosynthesis.

    31. Ylide-Substituted Thioxophosphanes and Dithioxophosphoranes (pages 1089–1091)

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

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310891

      Thumbnail image of graphical abstract

      A monomeric phosphorus(III)chalcogenide, thioxophosphane 1 was isolated and structurally characterized for the first time. Hitherto, thioxophosphanes of the type R[BOND]P[DOUBLE BOND]S, (R = halogen, alkyl, etc.) could be characterized only indirectly, because they are so reactive. The polar resonance structure is important for the description of the bonding of 1.

      • equation image
    32. Stereoselective Synthesis of C-Glycoside with a Glycosyl Dianion (pages 1091–1093)

      Dipl.-Chem. Valentin Wittmann and Prof. Dr. Horst Kessler

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310911

      Thumbnail image of graphical abstract

      No elimination of the functional group at position 2 occurs when the dilithio compound 1 reacts with a range of electrophiles “E”, for example aldehydes and methyl iodide, to give α-C-glucosides 2. Thus the flexible concept of C-elongation of pyranoses by umpolung at the anomeric center may be used for the direct synthesis of the 2-hydroxy compounds.

    33. Supramolecular Complexes of Flexible, Extended Cavity Calix[4]arenes—Structural Characterization of a Molecular Venus Flytrap (pages 1093–1094)

      Prof. Dr. Jerry L. Atwood, Dr. G. William Orr, Dr. Simon G. Bott and Dr. Kerry D. Robinson

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310931

      Thumbnail image of graphical abstract

      Depending on the size of the guest, the calix[4]arene 1 provides either a shallow or a deep narrow cavity. Already during its synthesis, 1 binds N-(2-hydroxyethyl)-N′-methylpiperazine in a large shallow cavity. The sodium salt 2 binds CH3CO2Et in a deep cavity.

  5. Book Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Correspondences
    5. Communications
    6. Book Reviews
    1. Book Review: Comprehensive Organic Synthesis. Selectivity, Strategy and Efficiency in Modern Organic Chemistry (pages 1095–1102)

      Ulrich Groth, Armin de Meijere, Uwe Beifuss, Johannes Belzner, Lutz F. Tietze, Günter von Kiedrowski and Oliver Reiser

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199310952

    2. Book Review: Tandem Organic Reactions. By Tse-Lok Ho (pages 1108–1109)

      H. Martin and R. Hoffmann

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199311081

    3. Book Review: Spectroscopy of Polymers. By J. L. Koenig (page 1109)

      Hans Wolfgang Spiess

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199311091

    4. New Books (Angew. Chem. Int. Ed. Engl. 7/1993) (page 1110)

      Article first published online: 22 DEC 2003 | DOI: 10.1002/anie.199311101

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