Chemistry - A European Journal

Cover image for Vol. 10 Issue 10

May 17, 2004

Volume 10, Issue 10

Pages 2355–2612

    1. Cover Picture: Multi-Step Application of Immobilized Reagents and Scavengers: A Total Synthesis of Epothilone C (Chem. Eur. J. 10/2004) (page 2355)

      R. Ian Storer, Toshiyasu Takemoto, Philip S. Jackson, Dearg S. Brown, Ian R. Baxendale and Steven V. Ley

      Version of Record online: 7 MAY 2004 | DOI: 10.1002/chem.200490030

      The cover picture, created by Doug Scard, offers a look over the tubulin horizon, depicting the bringing together of ingredients, solid-supported reagents and scavengers to produce the anti-tumour compound Epothilone C. Rather like a fine wine, the unwanted residues may be removed by filtration. For more information see the article by S. V. Ley et al. on p. 2529 ff.

    2. Catalytic Ionic Hydrogenations (pages 2366–2374)

      R. Morris Bullock

      Version of Record online: 16 APR 2004 | DOI: 10.1002/chem.200305639

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      Catalytic ionic hydrogenation of ketones occurs by proton transfer to a ketone from a cationic metal dihydride, followed by hydride transfer from a neutral metal hydride (illustrated here). Coordination of the ketone to the metal is not required. Since the important reactivity characteristics of the metal hydride involve H+ and H transfer reactions rather than insertion and elimination reactions, the reaction is successful with metals not traditionally used for hydrogenations, including inexpensive metals like molybdenum.

    3. A Versatile Polypeptide Platform for Integrated Recognition and Reporting: Affinity Arrays for Protein–Ligand Interaction Analysis (pages 2375–2385)

      Karin Enander, Gunnar T. Dolphin, Bo Liedberg, Ingemar Lundström and Lars Baltzer

      Version of Record online: 15 APR 2004 | DOI: 10.1002/chem.200305391

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      New recognition elements for protein-chip and biosensor applications: A flexible polypeptide platform for protein detection and quantification (see graphical representation), in which recognition is integrated with fluorescence monitoring of target-protein binding, is presented. An affinity array for the model protein carbonic anhydrase has been designed with different benzenesulfonamide derivatives attached to the polypeptide scaffold.

    4. Noncentrosymmetric Organic Solids with Very Strong Harmonic Generation Response (pages 2386–2390)

      Hong Zhao, Yong-Hua Li, Xi-Sen Wang, Zhi-Rong Qu, Li-Zhong Wang, Ren-Gen Xiong, Brendan F. Abrahams and Ziling Xue

      Version of Record online: 12 MAR 2004 | DOI: 10.1002/chem.200305425

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      Two chiral centers, rather than an expected Betti-type reaction product with only one chiral carbon center, are obtained in 14, which were generated by the molten reaction of 2-naphthol, 4-(aminomethyl)pyridine, and 4-pyridinecarboxaldehyde, or 3-pyridinecarboxaldehyde, or 4-cyanobenzaldehyde, or 4-cyanobenzaldehyde at about 180 °C. All of compounds are second harmonic generation active, and 1, 2, 4, may display ferroelectric behavior.

    5. Electronic and Vibrational Properties of Fluorenone in the Channels of Zeolite L (pages 2391–2408)

      André Devaux, Claudia Minkowski and Gion Calzaferri

      Version of Record online: 25 MAR 2004 | DOI: 10.1002/chem.200305673

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      Host–guest analysis: Fluorenone was inserted into the channels of zeolite L by gas-phase adsorption. Fluorenone shows unusual luminescence behavior in that it emits from two states. A model of the host–guest interaction is derived from the experimental results and calculations: the dye molecule sits close to the channel walls with the carbonyl group pointing towards an Al3+ site of the zeolite framework, as illustrated.

    6. A General Study of [(η5-Cp′)2Ti(η2-Me3SiC2SiMe3)]-Catalyzed Hydroamination of Terminal Alkynes: Regioselective Formation of Markovnikov and Anti-Markovnikov Products and Mechanistic Explanation (Cp′=C5H5, C5H4Et, C5Me5) (pages 2409–2420)

      Annegret Tillack, Haijun Jiao, Ivette Garcia Castro, Christian G. Hartung and Matthias Beller

      Version of Record online: 25 MAR 2004 | DOI: 10.1002/chem.200305674

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      A systematic study of the regioselective hydroamination of terminal alkynes in the presence of titanocene complexes is reported. Aliphatic amines give mainly the anti-Markovnikov imine, anilines and aryl hydrazines yield the Markovnikov isomer as main products (see scheme).

    7. Kinetic Precipitation of Solution-Phase Polyoxomolybdate Followed by Transmission Electron Microscopy: A Window to Solution-Phase Nanostructure (pages 2421–2427)

      Yan Zhu, Arthur Cammers-Goodwin, Bin Zhao, Alan Dozier and Elizabeth C. Dickey

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/chem.200305468

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      The structural nature of the polydisperse, nanoscopic components is elucidated both in the solution and the solid states of partially reduced polyoxomolybdate (see picture) derived from the {Mo132} keplerate, {(Mo)Mo5}12-{Mo2 acetate}30.

    8. Genuine Heteroleptic Complexes of Early Rare-Earth Metals: Synthesis, X-ray Structure, and Their Use for Stereospecific Isoprene Polymerization Catalysis (pages 2428–2434)

      Fanny Bonnet, Marc Visseaux, Denise Barbier-Baudry, Estelle Vigier and Marek M. Kubicki

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/chem.200305595

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      The real thing! Genuine heteroleptic early rare-earth metal complexes of general formula [Cp*′Ln{(p-tol)NN}(X)] (Cp*′ = C5Me4nPr, (p-tol)NN = (p-tol)NC(Me)CHC(Me)N(p-tol), X = BH4, Ln = Sm (1; see structure), Nd; X = Cl, Ln = Nd) have been obtained for the first time. In the presence of an alkylmagnesium activator, 1 behaves as an efficient and highly trans-specific catalyst for the polymerization of isoprene.

    9. Computational Approaches to Activity in Rhodium-Catalysed Hydroformylation (pages 2435–2444)

      Dieter Gleich and Jürg Hutter

      Version of Record online: 12 MAR 2004 | DOI: 10.1002/chem.200305179

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      New insights into rhodium-catalysed hydroformylation with regard to experimentally observed differences in activity of different complexes in this important homogeneously catalysed industrial process, were provided by static and dynamic quantum-mechanical calculations on unmodified (L=CO) and phosphane-modified (L=PF3, PH3, PMe3) model catalysts (see scheme).

    10. Synthesis of (E)-α-Hydroxy-β,γ-Unsaturated Amides with High Selectivity from α,β-Epoxyamides by Using Catalytic Samarium Diiodide or Triiodide (pages 2445–2450)

      José M. Concellón, Pablo L. Bernad and Eva Bardales

      Version of Record online: 10 MAR 2004 | DOI: 10.1002/chem.200305375

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      High stereoselectivity has been achieved in the isomerisation reaction of α,β-epoxyamides (1) by means of catalytic samarium diiodide or triiodide. The (E)-α-hydroxy-β,γ-unsaturated amides (2) were isolated with high stereoselectivity.

    11. Tris(oxalato)phosphorus Acid and Its Lithium Salt (pages 2451–2458)

      Ulrich Wietelmann, Werner Bonrath, Thomas Netscher, Heinrich Nöth, Jan-Christoph Panitz and Margret Wohlfahrt-Mehrens

      Version of Record online: 10 MAR 2004 | DOI: 10.1002/chem.200305208

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      An extremely acidic anion chelate complex tris(oxalato)phosphorus acid has been prepared from PCl5 and oxalic acid. It protonates diethyl ether and crystallizes from this solvent as [(Et2O)2H]+[P(C2O4)3]. First applications of the acid in a Friedel–Crafts-type reaction and of its lithium salt for non-aqueous electrolytes have been demonstrated (see scheme).

    12. Hydrogenation Studies Involving Halobis(phosphine)–Rhodium(i) Dimers: Use of Parahydrogen Induced Polarisation To Detect Species Present at Low Concentration (pages 2459–2474)

      Simon A. Colebrooke, Simon B. Duckett, Joost A. B. Lohman and Richard Eisenberg

      Version of Record online: 30 MAR 2004 | DOI: 10.1002/chem.200305466

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      Magnetisation transfer from the hydride ligands of binuclear complexes of the type [Rh(H)2(PPh3)2(μ-Cl)2(Rh)(PPh3)(alkene)] into the alkyl group of the hydrogenation product was observed. The complexes were obtained by reaction of [RhCl(PPh3)2]2 with parahydrogen and an alkene (see below). Although the iodide complexes [RhI(PPh3)2]2 and [RhI(PPh3)3] show higher initial activity, deactivation via the formation of the trirhodium phosphide bridged product, [(H)(PPh3)Rh(μ-H)(μ-I)(μ-PPh2)Rh(H)(PPh3)](μ-I)2Rh(H)2(PPh3)2 is relatively facile.

    13. Road Maps for Nitrogen-Transfer Catalysis: The Challenge of the Osmium(VIII)-Catalyzed Diamination (pages 2475–2486)

      Dirk V. Deubel and Kilian Muñiz

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/chem.200305467

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      Why is osmium(VIII)-catalyzed olefin diamination unknown although vicinal diols and amino alcohols can be synthesized from olefins by Sharpless dihydroxylation and aminohydroxylation (see scheme)? We present a density functional study towards an understanding of the reasons.

    14. A Catalytic Antibody against a Tocopherol Cyclase Inhibitor (pages 2487–2506)

      Roman Manetsch, Lei Zheng, Martine T. Reymond, Wolf-Dietrich Woggon and Jean-Louis Reymond

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/chem.200305629

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      Active antibodies against analogues: Catalytic antibody 16E7 was obtained by immunization against the guanidinium hapten 1, a transition-state analogue for the phenol–olefin cyclization catalyzed by tocopherol cyclase and an inhibitor of the corresponding enzyme. Antibody 16E7 is not a tocopherol cyclase, yet it catalyzes the conversion of enol ether 2 into hemiacetal 3 and the deprotonation of nitrobenzisoxazole 4 to form 2-cyano-4-nitrophenol 5. The antibody displays an unusual hysteresis effect, in that it requires several hours to reach full activity.

    15. Indium-Mediated Regio- and Diastereoselective Reduction of Norbornyl α-Diketones (pages 2507–2519)

      Faiz Ahmed Khan, Jyotirmayee Dash and Ch. Sudheer

      Version of Record online: 12 MAR 2004 | DOI: 10.1002/chem.200305656

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      Tolerable for a variety of sensitive substituents, such as acetate, ester, and bridgehead halogens, a novel methodolgy is described with which non-enolizable bicyclic α-diketones are converted efficiently and regio- and diastereoselectively into synthetically useful acyloins mediated by indium metal (see scheme). The methodology is extended to the synthesis of highly functionalized cyclopentane carboxaldehydes, potential building blocks in organic syntheses.

    16. Molecular Logic Gates Based on Pentacyanoferrate Complexes: From Simple Gates to Three-Dimensional Logic Systems (pages 2520–2528)

      Konrad Szaciłowski

      Version of Record online: 22 MAR 2004 | DOI: 10.1002/chem.200305663

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      Rapid development of computer techniques requires small and powerful logic gates, but silicon technology is reaching its physical limits. Chemical logic gates based on simple molecules may be the alternative solution. Even simple inorganic compounds, such as [Fe(CN)5NO]3−, may be used for advanced information processing. The diagram shows the electronic equivalent of a photochemical system described in this paper.

    17. Multi-Step Application of Immobilized Reagents and Scavengers: A Total Synthesis of Epothilone C (pages 2529–2547)

      R. Ian Storer, Toshiyasu Takemoto, Philip S. Jackson, Dearg S. Brown, Ian R. Baxendale and Steven V. Ley

      Version of Record online: 26 APR 2004 | DOI: 10.1002/chem.200305669

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      The combined application of immobilized reagents, catalysts and sequestering agents has been investigated as an advancing concept for multistep complex molecular assembly. This is illustrated in the context of synthetic routes to a convergent total synthesis of epothilone C (1).

    18. Crystallization-Induced Asymmetric Transformation of Chiral-at-metal Ruthenium(II) Complexes Bearing Achiral Ligands (pages 2548–2554)

      Olivier Hamelin, Jacques Pécaut and Marc Fontecave

      Version of Record online: 12 MAR 2004 | DOI: 10.1002/chem.200305749

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      Resolving ruthenium: Optically active chiral-at-metal ruthenium(II) complexes bearing only achiral ligands were efficiently and easily prepared in high yields and with good to excellent stereoselectivities from racemic mixtures by an original crystallization-induced asymmetric transformation (see scheme).

    19. Molecular Shuttles Based on Tetrathiafulvalene Units and 1,5-Dioxynaphthalene Ring Systems (pages 2555–2564)

      Seogshin Kang, Scott A. Vignon, Hsian-Rong Tseng and J. Fraser Stoddart

      Version of Record online: 23 MAR 2004 | DOI: 10.1002/chem.200305725

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      Six degenerate molecular shuttles incorporating either tetrathiafulvalene (TTF) units or 1,5-dioxynaphthalene (DNP) ring systems have been synthesized and characterized. Three different spacers were also incorporated between the two recognition sites and studied to determine their influence on the shuttling process (shown schematically). A negligible difference is observed in the barrier for shuttling between the three different spacers. Examination of the enthalpic and entropic activation parameters, however, reveals some small but interesting differences. The largest effect on shuttling appears to be a ground-state effect mediated by the strength of binding of the recognition unit. These thermodynamic parameters provide a basis for comparison to similar data in molecular electronic devices.

    20. The Advantage of Being Virtual—Target-Induced Adaptation and Selection in Dynamic Combinatorial Libraries (pages 2565–2580)

      Kay Severin

      Version of Record online: 12 MAR 2004 | DOI: 10.1002/chem.200305660

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      The adaptive behavior of simple dynamic combinatorial libraries upon addition of a target are described by numerical simulations (see picture). It is shown that the adaptation may lead to the amplification of molecules with a high affinity to the target, but only for specific boundary conditions.

    21. Solvent Effects on 195Pt and 205Tl NMR Chemical Shifts of the Complexes [(NC)5Pt[BOND]Tl(CN)n]n (n=0–3), and [(NC)5Pt[BOND]Tl[BOND]Pt(CN)5]3− Studied by Relativistic Density Functional Theory (pages 2581–2589)

      Jochen Autschbach and Boris Le Guennic

      Version of Record online: 25 MAR 2004 | DOI: 10.1002/chem.200305513

      The importance of modeling the chemical environment and the electronic structure of the title complexes for the calculation of their metal chemical shifts are discussed. All experimentally determined NMR parameters of the heavy nuclei for the series of complexes have now been computed with sufficient accuracy in order to allow for a detailed analysis of the experimentally observed trends.

    22. Syntheses and Reactions of Hexavalent Organotellurium Compounds Bearing Five or Six Tellurium[BOND]Carbon Bonds (pages 2590–2600)

      Masataka Miyasato, Takao Sagami, Mao Minoura, Yohsuke Yamamoto and Kin-ya Akiba

      Version of Record online: 31 MAR 2004 | DOI: 10.1002/chem.200305260

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      Five- and six-coordinate tellurium compounds: Hexaorganotellurium compounds, Ar6−n(CH3)nTe (Ar=Ph, 4-CF3C6H4, 4-CH3C6H4, 4-BrC6H4) and Ar5(R)Te (R=4-CH3OC6H4, vinyl, PhSCH2, nBu), and pentaorganotellurium halides, Ar5TeX (X=Cl, Br) and (4-CF3C6H4)4(CH3)TeX, were synthesized by a variety of methods (see scheme). Electrophilic halogenation of the hexaorganotellurium compounds is also described.

    23. Synthesis of C3 Benzo[1,2-e:3,4-e′:5,6-e′′]tribenzo[l]acephenanthrylenes (“Crushed Fullerene” Derivatives) by Intramolecular Palladium-Catalyzed Arylation (pages 2601–2608)

      Berta Gómez-Lor, Esther González-Cantalapiedra, Marta Ruiz, Óscar de Frutos, Diego J. Cárdenas, Amelia Santos and Antonio M. Echavarren

      Version of Record online: 31 MAR 2004 | DOI: 10.1002/chem.200306023

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      A triple palladium-catalyzed arylation, which occurs with concomitant dehydrogenation, has been used to synthesize the C60H30 polyarene benzo[1,2-e:3,4-e′:5,6-e′′]tribenzo[l]acephenanthrylene (see scheme). Similarly, a derivative functionalized at C3, C13, and C23 has been synthesized by the same strategy.

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      Preview: Chem. Eur. J. 10/2004 (page 2612)

      Version of Record online: 7 MAY 2004 | DOI: 10.1002/chem.200490032