Angewandte Chemie International Edition in English

Cover image for Vol. 36 Issue 22

December 1, 1997

Volume 36, Issue 22

Pages 2391–2531

Currently known as: Angewandte Chemie International Edition

    1. Cover Picture (Angew. Chem. Int. Ed. Engl. 22/1997)

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199723891

      Thumbnail image of graphical abstract

      The cover picture shows a stick model of an aggregated calix[4]arenoporphyrin derived from crystal-structrue coordinates (oxygen atoms of one molecule are represented in red, and nickel atoms as glass balls; the second molecule is depicted by fainter sticks). Aggregations of two molecules to give a cogwheel arragement is clearly a dominant structural phenomenon. Combination of calix[4]arenes, which posses strong ion-bonding properties, with porphyrins, which are pH-dependent photoactive chromophores, can potentially lead to new molecular receptors for the development of efficent sensors. Calix[4]arenoporphyrins may also serve as potential models for biological systems such as the tetrapyrrole units in the light-harvesting component of bacterial LH2. More about this suprmolecular array is reported by K. M. Smith and co-workers on pages 2497–2500. The graphic was generated by Philippe Schmitt, University of Oxford, UK, with the programs POV-Ray 3.0 and POV-Chem.

  1. Reviews

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Homoleptic Metal Carbonyl Cations of the Electron-Rich Metals: Their Generation in Superacid Media Together with Their Spectroscopic and Structural Characterization (pages 2402–2425)

      Prof. Dr. Helge Willner and Prof. Dr. Friedhelm Aubke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724021

      Thumbnail image of graphical abstract

      Predominantly σ-bonded CO ligands are encountered in homoleptic carbonyl cations of electronrich metals (Groups 8–12; see diagram on the right). As a result of the severely reduced π-backbonding. the cations. which can all be generated in superacid media and form exclusively as thermally stable compounds with [Sb2F11], are impressive examples of a new class of coordination compounds of CO with unprecedented spectroscopic properties.

    2. Phanes with Three- and Four-Membered Rings as Building Elements (pages 2426–2439)

      Prof. Dr. Rolf Gleiter and Dr. Martin Merger

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724261

      Thumbnail image of graphical abstract

      Amazing advances in the synthesis of small-ring cyclophanes are presented here. Carbene addition can be used much more selectively for cyclopropenations than before. In the presence of transition metal complexes, cyclodiynes dimerize to cyclobutadienosuperphanes such as 1. Theoretical investigations and X-ray crystal structure analyses support the obtained results.

  2. Highlights

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Boryl Metal Complexes, Boron Complexes, and Catalytic (Hydro)boration (pages 2441–2444)

      Priv.-Doz. Dr. Hubert Wadepohl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724411

      Thumbnail image of graphical abstract

      Boryl metal complexes are not old hat, as demonstrated by the great interest in this class of compounds in recent years. Today, the importance of these complexes lies mainly in their role as intermediates in borylations catalyzed by transition metals [Eq. (1)], for which there are numerous synthetic applications. With regard to new types of structures, the combinations metal complex/borane continues to produce many novelties, for example σ complexes of type 1.

    2. Organic Tri- and Tetraradicals with High-Spin or Low-Spin States (pages 2445–2448)

      Dr. Werner M. Nau

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724451

      Thumbnail image of graphical abstract

      The toolbox for spin coupling is now well equipped, since nearly all possible topologies of organic tri- and tetraradicals are known, which can be applied as building blocks for the synthesis of practically useful polyradical materials. High-spin polyradicals could be useful as organic ferromagnets, whereas several low-spin polyradicals are suggested to support electric conductivity. An example of the latter is the derivative of the singlet tetraradical 1, in which both ferromagnetic and anti-ferromagnetic coupling operate.

  3. Communications

    1. Top of page
    2. Reviews
    3. Highlights
    4. Communications
    5. Book Reviews
    1. Synthesis, Structural Characterization, and Reactivity of Novel Zirconium(IV) Complexes Containing the Tropidinyl Ligand (pages 2450–2452)

      Dr. Gino G. Lavoie and Prof. Robert G. Bergman

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724501

      Thumbnail image of graphical abstract

      Isoelectronic to cyclopentadienyl but less symmetrical: the tropidinyl (trop) ligand. Therefore, in the stable complexes [(trop)2ZrCl2] (1) and [(trop)2ZrMe2], the two trop ligands are rotated by 77 and 88° with respect to one another. Preliminary investigations show that 1 catalyzes the polymerization of ethylene.

    2. High LaIII Affinity of a Bis(spirobenzopyran) Azacrown Ether and Photoinduced Switching of its Ion Selectivity between Multivalent and Monovalent Metal Ions (pages 2452–2454)

      Prof. Dr. Keiichi Kimura, Tomohito Utsumi, Takashi Teranishi, Prof. Dr. Masaaki Yokoyama, Dr. Hidefumi Sakamoto, Masanori Okamoto, Prof. Dr. Ryuichi Arakawa, Hiroshi Moriguchi and Yoko Miyaji

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724521

      Thumbnail image of graphical abstract

      The transition between the merocyanine and spiropyran forms switches the selectivity of the bis(spiropyran) azacrown ether 1 from La3+ to K+ [Eq. (1)]. Thus, 1 offers much greater possibilities for selectivity control between multi- and monovalent metal ions than the corresponding unsubstituted azacrown ether.

    3. Ion-Exchange Resins for Combinatorial Synthesis: 2,4-Pyrrolidinediones by Dieckmann Condensation (pages 2454–2455)

      Dr. Bheemashankar A. Kulkarni and Dr. Arasu Ganesan

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724541

      Thumbnail image of graphical abstract

      By temporary immobilization on a quaternary ammonium resin (Amberlyst 26-A, OH form), the acidic 2,4-pyrrolidinediones (tetramic acids) could be purified immediately after being synthesized by a Dieckmann condensation of amide esters that was catalyzed by this resin [Eq. (a)]. R1 [DOUBLE BOND] H, alkyl, benzyl; R2 = phenyl, aryl; R3 [DOUBLE BOND] CN, o-O2NC6H4, P(O)(OEt)2.

    4. Insertion of Carbenoids into Cp[BOND]H Bonds of Ferrocenes: An Enantioselective-Catalytic Entry to Planar-Chiral Ferrocenes (pages 2456–2458)

      Dipl.-chem. Stephan Siegel and Prof. Dr. Hans-Günther Schmalz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724561

      Thumbnail image of graphical abstract

      Not only significant enantioselectivities, but also chemical yields that are clearly higher than with achiral catalysts are seen for the asymmetric variant of the transition metal catalyzed cyclization of diazoketones such as 1. The carbene chemistry known for the functionalization of benzene derivatives has now been transferred to ferrocene for the first time.

    5. Asymmetric Self-Replication of Chiral 1,2-Amino Alcohols by Highly Enantioselective Autoinductive Reduction (pages 2458–2460)

      Dr. Takanori Shibata, Tomohide Takahashi, Takashi Konishi and Prof. Dr. Kenso Soai

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724581

      Thumbnail image of graphical abstract

      The product triggers the enantioselectivity. This concept is exemplified by the reduction of α-amino ketones with lithium aluminum hydride shown in Equation (1). By first modifying the reducing agent with product alcohols as chiral ligands, yields of 65–93% and ee values of 69–90% ee are obtained.

    6. Chiral Methyl-Branched Surfactants and Phospholipids: Synthesis and Properties (pages 2460–2462)

      Dr. Michael Morr, Dr. Jens Fortkamp and Stefan Rühe

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724601

      Thumbnail image of graphical abstract

      The number of methyl groups on the acyl groups of phosphatidylcholines 1 (R1–R4 = H, CH3) determines their surfactant characteristics. Differential calorimetric investigations show that little or even no branching leads to ordered gel phases. The behavior of the compounds at the water–air interface is also determined by these structural factors.

    7. A Supercharged Anion with a Silyl-Substituted Eight-Center, Twelve-Electron π System: Synthesis and Characterization of the Tetralithium Salt of an Octasilyl-Substituted Trimethylenecyclopentene Tetraanion (pages 2462–2464)

      Prof. Dr. Akira Sekiguchi, Dipl.-Chem. Tsukasa Matsuo and Dr. Chizuko Kabuto

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724621

      Thumbnail image of graphical abstract

      Orange crystals of the tetralithium salt of the tetraanion 1 were isolated from the reduction of the neutral octasilyl-substituted trimethylenecyclopentene compound with lithium in THF. The tetraanion 1 is the first example of an eight-center, twelve-electron π system.

    8. Tetradecanuclear Molybdenum (Tungsten)/Copper/Sulfur Heterobimetallic Clusters [(nBu)4N]4[M4Cu10S16O2E]·H2O, (M = Mo, E = O; M = W, E = 1/2O + 1/2S) (pages 2464–2466)

      Jun Guo, Prof. Xintao Wu, Wenjian Zhang, Tianlu Sheng, Qun Huang, Ping Lin, Quanming Wang and Jiaxi Lu

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724641

      Thumbnail image of graphical abstract

      Self-assembly with incorporation of sulfur ligands into the systems [MSnO4-n]2−/Cu+ (M [DOUBLE BOND] Mo, W; n = 3, 4) leads to the synthesis of salts 1 and 2. The framework of their anoins is shown schematically on the right. It consists of one cubane-like Cu3MS3E fragment, one trigonal-prismatic Cu3MS4 fragment, and two butterfly-type Cu2MS3O fragments that are bridged by one μ4-S and two μ3-S atoms. Clusters such as 1 and 2 are of interest inter alia as models for the active centers of some enzymes.

      • equation image
    9. Olefin Metathesis in Compressed Carbon Dioxide (pages 2466–2469)

      Priv.-Doz. Dr. Alois Fürstner, Daniel Koch, Klaus Langemann, Priv.-Doz. Dr. Walter Leitner and Christian Six

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724661

      Thumbnail image of graphical abstract

      The product distribution can be controlled by varying the density of the reaction medium when olefin metatheses of acyclic dienes are carried out in supercritical CO2 (scCO2), as shown below. Substrates with NH groups, which are generally not tolerated in conventional solvents, are compatible with Ru-based metathesis catalysts in scCO2. Avoidance of potentially hazardous organic solvents, simple isolation of the products, and the recovery of the catalysts in active form are additional practical advantages associated with using compressed CO2 as reaction medium for ring-closing metathesis (RCM) and ring-opening metathesis polymerization (ROMP).

    10. Unusual Regioselectivity in the Reductive Coupling of Alkynes and Allenes by Hydrozirconation and Zinca-Claisen Rearrangement (pages 2469–2471)

      Prof. Dr. Keisuke Suzuki, Takahiro Imai, Shigeo Yamanoi, Masao Chino and Dr. Takashi Matsumoto

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724691

      Thumbnail image of graphical abstract

      The α-adduct is the sole product of the coupling of vinyl- and allylzirconium compounds with ZnCl2 (see below), provided no MgII salts are present. The zirconium compounds are formed in situ from alkynes and allenes, and the overall reaction opens a new preparative route to the vitamin E side chain through asymmetric induction in the 1,5-position. R1 = CH2OCPh3, R2 = CHMeCH2OCH2OMe, “Zr” = [Cp2Zr(H)Cl].

    11. Copper Pnictogenides as Selective Reagents: A New Access to Functionalized Phosphanes and Arsanes (pages 2471–2473)

      Dipl.-Chem. Christian Meyer, Prof. Dr. Hansjörg Grützmacher and Dr. Hans Pritzkow

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724711

      Thumbnail image of graphical abstract

      Use of bipyridine, phenanthroline, or neocuproine as the co-ligand results in fine-tuning of the reactivity of copper(I) pnictogenide complexes with respect to organohalides. This therefore allows the selective synthesis of functionalized phosphanes (1) and arsanes as well as mixed phosphanyl arsanes (2).

    12. Substrate Mimetic Mediated Peptide Synthesis: An Irreversible Ligation Strategy That Is Independent of Substrate Specificity (pages 2473–2475)

      Frank Bordusa, Dr. Dirk Ullmann, Christian Elsner and Prof. Dr. Hans-Dieter Jakubke

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724731

      Thumbnail image of graphical abstract

      Cationic specificity determinants of substrate mimetics 1 bind optimally to the binding site of highly specific proteases that normally determines their primary specificity. This designed imitation not only allows trypsin-catalyzed nonspecific and irreversible peptide-bond formation, but now also the use of thrombin and especially the cystein protease clostripain, which acts as the most efficient peptide ligase.

    13. Stabilization of a C2v-Distorted Methane Derivative in an Organometallic Framework (pages 2475–2477)

      Dipl.-Chem. Jörg Schottek, Prof. Dr. Gerhard Erker and Dr. Roland Fröhlich

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724751

      Thumbnail image of graphical abstract

      An intramolecular ion-pair interaction stabilizes the unusual, distorted coordination geometry of C1 in 1. In the course of the topomerization 1ent-1, which was followed by NMR spectroscopy, the internal Zr ⃛CH2 ion pair must be cleaved. The rearrangement pathway probably proceeds via a species with “normal” tetrahedral coordination geometry at C1.

    14. Intramolecular Hydrocarbonation of α-Alkynyl Malononitriles Catalyzed by Palladium Olefin Complexes (pages 2477–2480)

      Dr. Naofumi Tsukada and Prof. Dr. Yoshinori Yamamoto

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724771

      Thumbnail image of graphical abstract

      A [(cod)Pd0] species is the catalyst for the title reaction. ε-Alkynyl malononitriles 1 cyclize selectively in the process to give (Z)-alkylidenecyclopentanes 2 in good to very good yields. Phosphanepalladium complexes are significantly less effective in this reacton than alkenepalladium compounds. cod = 1,5-cyclooctadiene.

    15. Ligand Effects in Diastereoselective Additions of Organocerium Reagents to Carbonyl Substrates (pages 2480–2482)

      Dr. Carmen Alcaraz and Prof. Dr. Ulrich Groth

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724801

      Thumbnail image of graphical abstract

      Low basicity and high nucleophilicity are the important characteristics of organocerium reagents that make them suitable for reactions with readily enolizable substrates such as the cyclopentanone derivative shown below. The organocerium compounds presented here add to such carbonyl substrates in a highly selective fashion and afford the corresponding alcohol in excellent yields; increasing the steric hindrance of the reagent leads to higher diastereoselectivity.

    16. Template-Mediated Self Assembly of Six- and Eight-Membered Iron Coronates (pages 2482–2485)

      Prof. Dr. Rolf W. Saalfrank, Dipl.-Chem. Ingo Bernt, Eveline Uller and Dr. Frank Hampel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724821

      Thumbnail image of graphical abstract

      The type of bait determines the prey: in a pond with triethanolamine ligands and iron(III) ions, six- (1) or eight-membered (2) iron coronates can be captured, depending upon whether sodium or cesium ions are used as the bait. This finding is especially interesting in connection with a possible combinatiorial approach in supramolecular chemistry.

    17. Specific Recognition of a Minimal Model of Aminoacylated tRNA by the Elongation Factor Tu of Bacterial Protein Biosynthesis (pages 2485–2489)

      Priv.-Doz. Dr. Stefan Limmer, Dipl.-Chem. Martin Vogtherr, Dr. Barbara Nawrot, Dipl.-Biol. Rainer Hillenbrand and Prof. Dr. Mathias Sprinzl

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724851

      Thumbnail image of graphical abstract

      Anthraniloyladenosine 1 binds specifically to the elongation factor Tu of the bacterial protein biosynthesis. The structure and binding features in the molecular recognition of 1, which acts as a mimetic of charged tRNA, could be inferred from detailed NMR investigations.

    18. Electrostatic Layering of Giant Vesicles (pages 2489–2491)

      Prof. Fredric M. Menger and Jason S. Keiper

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724891

      Thumbnail image of graphical abstract

      Two giant vesicles of opposite charge are seen by phase-contrast microscopy to “snap together” when brought into contact with each other. One of the vesicles then bursts, thereby surrounding the other with a layer of opposite charge (shown schematically below). The process can be repeated to construct alternating layers.

    19. Addition of Azaenolates to Simple, Unactivated Olefins (pages 2491–2493)

      Dr. Katsumi Kubota and Prof. Eiichi Nakamura

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724911

      Thumbnail image of graphical abstract

      An olefinic analogue of the aldol reaction makes possible the ready synthesis of ketones by coupling the three components: zinc hdrazone, olefin (e. g. ethylene or styrene), and electrophile E+ (see below). Fine-tuning the electronic properties of the carbometalated hydrazone is decisive for the success of this reaction.

    20. Ligand-Mediated Coupling of Organometallic Reaction Centers (pages 2493–2495)

      Prof. Dr. Wolfgang Kaim, Dr. Ralf Reinhardt and Dr. Jan Fiedler

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724931

      Thumbnail image of graphical abstract

      Electron-reservoir behavior, the formation of RhI/RhII mixed-valent species, and the separation of redox processes and thus “communication” between individual reaction centers were established in a first systematic study of the ligand-mediated coupling of two equivalent “chemical” redox (ECE) reaction centers (E = electron transfer, C = chemical step (here dissociation of chloride); see scheme on the right, Cp* = C5Me5, L = multidentate ligand).

    21. Isolation and X-ray Structural Determination of Both Folded and Twisted Conformers of Bis{4H,8H-4-(dicyanomethylene)-benzo[1,2-c:4,5-c′]bis[1,2,5]thiadiazol-8-ylidene}, an Overcrowded Ethylene with High Electron Affinity (pages 2495–2497)

      Prof. Takanori Suzuki, Takanori Fukushima, Prof. Tsutomu Miyashi and Prof. Takashi Tsuji

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724951

      Thumbnail image of graphical abstract

      Reversible machano- and thermochromic behavior are-features of the title bis(tricyclic) olefin. These characteristics are a consequence of the different proper ties of the interconvertible folded and twisted confomers. Despite the severe molecular deformation the conductive charge-transfer complexes and stable salts of the radical anion could be isolated due to their strong electron affinity.

    22. A Calix[4]arenoporphyrin (pages 2497–2500)

      Richard G. Khoury, Dr. Laurent Jaquinod, Dr. Katsuhiro Aoyagi, Dr. Marilyn M. Olmstead, Dr. Andrew J. Fisher and Prof. Dr. Kevin M. Smith

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199724971

      Thumbnail image of graphical abstract

      All four porphyrin units on the same side—that is the surprising conformation adopted by calixarene 1. A “cogwheel” dimeric structure was identified for the compound in the solid state, in which π–π aggregation is the dominating structural feature.

    23. Synthesis, Structure, and Double Olefin Extrusion of All Three Diastereomers of 2,2,6,6-Tetrakis(4-chlorophenyl)-3,7-dimethyl-4-phenyl-1,5-dioxa-4λ5-phosphaspiro[3.3]heptane (pages 2500–2502)

      Prof. Dr. Takayuki Kawashima, Rei Okazaki and Prof. Dr. Renji Okazaki

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725001

      Thumbnail image of graphical abstract

      A distorted tetragonal-pyramidal structure is adopted by the trans-trans diastereomer of the spirophos-phorane 1. In contrast, the cis-trans isomer displays a distorted trigonal-bipyramidal structure. These two as well as the cis-cis diastereomer were synthesized as stable crystals by taking advantage of electronic and steric effects of the methyl groups in the 3- and 7-positions. Interestingly, thermolysis of 1 gave two molar equivalents of Ar2C[DOUBLE BOND]CHMe. Ar = 4-ClC6H4.

    24. Hexaaryltetrasilabuta-1,3-diene: A Molecule with Conjugated Si[BOND]Si Double Bonds (pages 2503–2504)

      Prof. Dr. Manfred Weidenbruch, Dipl.-Chem. Stefan Willms, Dipl.-Chem. Wolfgang Saak and Prof. Dr. Gerald Henkel

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725031

      Thumbnail image of graphical abstract

      The first tetrasilabuta-1,3-diene (2) was obtained as reddish-brown crystals simply and unexpectedly by lithiation of disilene 1, partial bromination with an aryl bromide, and intermolecular cleavage of lithium bromide. The conjugation between the two Si[BOND]Si double bonds of 2 was demonstrated by electron spectroscopy and X-ray crystallography. Mes = 2,4,6-Me3C6H2, Tip = 2,4,6-iPr3C6H2.

    25. Synergism between the Guest Compound and the Host Framework in Zeolite CsNaY after Impregnation with Cesium Hydroxide (pages 2504–2506)

      Priv.-Doz. Dr. Michael Hunger, Dipl.-Phys. Udo Schenk, Dr. Beate Burger and Prof. Dr.-Ing. Jens Weitkamp

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725041

      Thumbnail image of graphical abstract

      An increase in the basicity of the zeolite host, which is determined by the oxide guest component, was observed for the first time with a zeolite impregnated with cesium hydroxide (a section of the structure is shown on the right; ○ cations, • guest component). The application of such materials as basic solid-state catalysts could be of interest for the chemical industry.

    26. 1,8-Bis(allylstannyl)naphthalene Derivatives as Neutral Allylation Agents: Rate Acceleration by Chelation-Induced Lewis Acidity (pages 2507–2509)

      Dr. Naoki Asao, Dr. Pingli Liu and Prof. Keiji Maruoka

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725071

      Thumbnail image of graphical abstract

      A large variety of carbonyl substrates can be allylated with 1 under neutral conditions. In the case of dicarbonyl compounds, products 2 form chemoselectively. The driving force of this reaction is ascribed to the latent Lewis acidity, which is induced by chelation of neutral, bidentate bis(stannane)s on the carbonyl group (structure A).

    27. Copper(I) Helicates Containing Bridging But Nonchelating Polypyridine Fragments (pages 2509–2511)

      Dr. Raymond Ziessel, Prof. Anthony Harriman, Dr. Jean Suffert, Dr. Marie-Thérèse Youinou, Dr. André De Cian and Prof. Jean Fischer

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725091

      Thumbnail image of graphical abstract

      The isolation of a mononuclear key intermediate and the measurement of stability constants gave insight into the stepwise formation of helicates (depicted on the right) consisting of copper(I) ions and oligopyridine ligands. A positive cooperativity for cation binding is not mandatory for helicate formation.

    28. Photochemical Synthesis of Polyrotaxanes from Stilbene Polymers and Cyclodextrins (pages 2511–2514)

      Wolfgang Herrmann, Dr. Maria Schneider and Prof. Dr. Gerhard Wenz

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725111

      Thumbnail image of graphical abstract

      The additional inclusion of stilbene monomers within cyclodextrin rings strung on a stilene polymer leads to a supramolecular stabilization of the molecular necklace. This assembly can be transformed into a polyrotaxane (see drawing below) by photochemical formation of tetraphenylcyclobutane blocking groups.

    29. New Reactions of a Silylene: Insertion into M[BOND]N Bonds of M[N(SiMe3)2]2 (M [DOUBLE BOND] Ge, Sn, or Pb) (pages 2514–2516)

      Dr. Barbara Gehrhus, Dr. Peter B. Hitchcock and Prof. Michael F. Lappert

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725141

      Thumbnail image of graphical abstract

      The first insertion of a silylene into a M[BOND]N bond was observed in the presented transformations of the thermally stable silylene 1, Np = neopentyl, with metal(II) bis(silyl)amides. Bis(silyl)metal(II) compounds 2 and 3 were obtained for M = Sn and Pb, respectively, whereas a colorless azadisilager-mole was formed for M [DOUBLE BOND] Ge. Noteworthy is the very long Sn[BOND]Si bond of 2.712(2) Å in 2.

    30. Platinum-Catalyzed Regioselective Silaboration of Alkenes (pages 2516–2518)

      Dr. Michinori Suginome, Hiroshi Nakamura and Prof. Dr. Yoshihiko Ito

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725161

      Thumbnail image of graphical abstract

      2-Boryl-1-silylalkanes form regioselectively upon addition of a B[BOND]Si bond to the C[BOND]C double bond of simple terminal alkenes in the presence of a (triphenylphosphane)platinum complex as catalyst [Eq. (1)]. At the B[BOND]C bond, homologation by one C atom is possible.

    31. A Crossed Yne–Ene Metathesis Showing Atom Economy (pages 2518–2520)

      Dipl.-Chem. Roland Stragies, Dr. Matthias Schuster and Prof. Dr. Siegfried Blechert

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725181

      Thumbnail image of graphical abstract

      No special functional groups are required for a new method of selective C[BOND]C coupling of monosubstituted alkynes such as 1 with alkenes like 2. This crossed yne–ene metathesis also proceeds with atom economy, and provides easy access to such interesting synthetic building blocks as the 1,3-substituted diene 3.

    32. Total Synthesis of Eleutherobin (pages 2520–2524)

      Prof. Dr. K. C. Nicolaou, Dr. Floris van Delft, Dr. Takashi Ohshima, Dr. Dionisios Vourloumis, Dr. Jinyou Xu, Dr. Seijiro Hosokawa, Jeffrey Pfefferkorn, Dr. Sanghee Kim and Dr. Tianhu Li

      Version of Record online: 22 DEC 2003 | DOI: 10.1002/anie.199725201

      Thumbnail image of graphical abstract

      Taxol-like activity is exhibited by eleutherobin (1), one of the most promising antitumor agents isolated from nature in recent years. The first total synthesis of this compound also provided a route to two biologically active analogues, thus enabling the first structure–activity relationships within the eleutherobin family to be established.

  4. Book Reviews

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