Angewandte Chemie International Edition

Cover image for Vol. 42 Issue 1

January 3, 2003

Volume 42, Issue 1

Pages 1–127

    1. Cover Picture: Angew. Chem. Int. Ed. 1/2003 (page 1)

      Hong Lin and Samuel J. Danishefsky

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390033

      The Art of Synthesis and the beauty of Nature lure so many chemists into total synthesis. The cover picture shows yellow jasmine in full bloom, from which the poisonous alkaloid gelsemine was isolated. The formula of gelsemine and important intermediates from six total syntheses are overlaid on the photograph. From these syntheses, we can learn which strategies represent the fastest and/or most efficient routes to the target. More about this fascinating compound and organic synthesis at its best can be found in the Review by S. J. Danishefsky and H. Lin on pg. 36 ff.

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      Editorial: You're only as good as your last success (page 4)

      Peter Gölitz

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390049

    3. Web Site: What's Cooking on the Web? (page 20)

      Hervé This

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390042

    4. Welding, Organizing, and Planting Organic Molecules on Substrate Surfaces—Promising Approaches towards Nanoarchitectonics from the Bottom up (pages 24–26)

      Stefan Hecht

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390045

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      Single molecule reactivity, self-assembly, and self-directed growth can be used to generate patterns on the nanometer scale. For example, molecular building blocks can be organized on substrate surfaces (see picture). New approaches that take advantage of single-molecule reactivity and self-organization, as well as stabilization of structures on substrate surfaces, are introduced.

    5. Bistable Electrical, Optical, and Magnetic Behavior in a Molecule-Based Material (pages 27–29)

      Joel S. Miller

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390046

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      Neutral alkyl-substituted spirobiphenalenyl radicals (see formula) were recently reported that exhibit bistability as a consequence of temperature-dependent hysteretic switching. The high- and low-temperature forms display significant differences in their electrical, optical, and magnetic properties.

    6. Hadamard Transform Time-of-Flight Mass Spectrometry: More Signal, More of the Time (pages 30–35)

      Richard N. Zare, Facundo M. Fernández and Joel R. Kimmel

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390047

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      Success squared! The French mathematician Jacques Hadamard (1865–1963; pictured) significantly improved the analysis of complex signals by introducing a decomposition based on square waves. A review is presented of the application of the Hadamard transform to time-of-flight mass spectrometry. The primary benefit of this technique is the gain in signal-to-noise ratio associated with signal multiplexing.

    7. Gelsemine: A Thought-Provoking Target for Total Synthesis (pages 36–51)

      Hong Lin and Samuel J. Danishefsky

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390048

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      Seven total syntheses of the title compound 1 have already been reported. In this Review, the authors discuss the fascinating strategies (e.g. see scheme) employed in the various assemblies of the key fragments, including the quaternary center C20, the oxindole moiety, and the bicyclooctane residue.

    8. Thin-Chip Microspray System for High-Performance Fourier-Transform Ion-Cyclotron Resonance Mass Spectrometry of Biopolymers (pages 53–58)

      Joël S. Rossier, Nikolay Youhnovski, Niels Lion, Eugen Damoc, Susanne Becker, Frédéric Reymond, Hubert H. Girault and Michael Przybylski

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390050

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      Microchip innovation: A thin-film microchip system has been developed for microelectrospray Fourier-transform ion-cyclotron resonance mass spectrometry. Application perspectives include the analysis of combinatorial libraries and high-performance proteomics (as shown for the peptide fragment of the phosphorylation domain (512–538) of human neurofibrillary tau protein; the seven phosphorylation sites are indicated in red).

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      Morphosynthesis of Star-Shaped Titania–Silica Shells (pages 58–61)

      Dirk Volkmer, Stefano Tugulu, Matthias Fricke and Tim Nielsen

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390051

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      A self-organized dynamic growth process (“morphosynthesis”) involving mineral formation at a membrane-type surface leads to discrete inorganic shells of star-shape morphology (see picture). CTAB=cetyltrimethylammonium bromide.

    10. Measurement of a Cu[BOND]Cu Distance of 26 Å by a Pulsed EPR Method (pages 62–64)

      Irene M. C. van Amsterdam, Marcellus Ubbink, Gerard W. Canters and Martina Huber

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390053

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      Distances between paramagnetic transition-metal ions in compounds can be studied by using the pulsed electron–electron double-resonance method. Hereby, the relative orientation (red arrow) of the metal centers (CuII, blue sphere), as well as the principal axes of the g tensor (green arrows) relative to the ligands play an important role (schematic representation: dimer of the copper protein azurin).

    11. An Efficient Method for Controlled Propylene Oxide Polymerization: The Significance of Bimetallic Activation in Aluminum Lewis Acids (pages 64–68)

      Wigand Braune and Jun Okuda

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390054

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      Combined strength: Only the combination of aluminate complexes with their neutral Lewis acids allows the controlled regioregular ring-opening polymerization of industrially important propylene oxide. The chain propagation proceeds at both aluminium centers according to a novel mechanism (see scheme).

    12. Block-Selected Molecular Recognition and Formation of Polypseudorotaxanes between Poly(propylene oxide)-Poly(ethylene oxide)-Poly(propylene oxide) Triblock Copolymers and α-Cyclodextrin (pages 69–72)

      Jun Li, Xiping Ni and Kam Leong

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390055

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      Although a poly(propylene oxide) (PPO) chain was previously thought to be impenetrable to α-cyclodextrin, the middle poly(ethylene oxide) (PEO) block of PPO-PEO-PPO triblock copolymers can be selectively recognized and included by α-cyclodextrin to form polypseudorotaxanes (see schematic representation), even though it is flanked by two PPO blocks.

    13. Aligning a Single-Lipid Nanotube with Moderate Stiffness (pages 72–74)

      Hiroshi Frusawa, Akihiro Fukagawa, Yuki Ikeda, Jun Araki, Kohzo Ito, George John and Toshimi Shimizu

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390056

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      Bendy tubes: Lipid nanotubes can be aligned by a novel and simple method, whereby a fine line of a single nanotube is drawn freely by microinjecting the aqueous dispersion onto a glass plate. This technique is simple and highly adaptable; even words can be written (see picture)! The tubes can be bent and their Young's modulus measured by manipulation with optical tweezers.

    14. Channels and Cavities Lined with Interlocked Components: Metal-Based Polyrotaxanes That Utilize Pyridinium Axles and Crown Ether Wheels as Ligands (pages 74–77)

      Gregory J. E. Davidson and Stephen J. Loeb

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390057

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      One- and two-dimensional coordination polymers (see picture) in which the bridging ligands are coated with crown ethers (red) can be prepared by metal–ligand self-assembly. These metal-based polyrotaxanes contain channels and cavities that are lined with mechanically linked molecular components. This structural design has significant potential for tuning the physical properties of internal cavities and the production of materials that contain functional molecular entities that may be addressable or controllable.

    15. Perfluorinated meso-Aryl-Substituted Expanded Porphyrins (pages 78–82)

      Soji Shimizu, Ji-Young Shin, Hiroyuki Furuta, Rami Ismael and Atsuhiro Osuka

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390058

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      Twisted figure-of-eight structures are found for the perfluorinated meso-aryl-substituted expanded porphyrins synthesized from 3,4-difluoropyrrole and pentafluorobenzaldehyde under modified Rothemund–Lindsey conditions. The crystal structure of the [26]hexaphyrin (see picture) consists of two almost planar tripyrrolic subunits which are tilted by approximately 60° in which a distinct alternation in the bond lengths of the π-electronic system is evident.

    16. A Biomimetic Synthesis of Thiazolines Using Hexaphenyloxodiphosphonium Trifluoromethanesulfonate (pages 83–85)

      Shu-Li You, Hossein Razavi and Jeffery W. Kelly

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390059

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      Most chemical syntheses of thiazolines use serine residues, whereas nature employs cysteine residues. In a biomimetic approach, [(Ph3P+)2O](OTf)2 was used to promote triphenylmethyl (Tr) deprotection and dehydrocyclization of simple cysteine N-amides to give thiazolines in excellent chemical and optical yields (see scheme). This mild method was extended to the synthesis of, for example, thiazolines from cysteine-containing dipeptides in high yield and without significant loss of chirality at the C2-exomethine carbon atom. TF=trifluoromethanesulfonyl, Cbz=benzyloxycarbonyl

    17. Hydrogen Bonds around M(μ-O)2M Rhombs: Stabilizing a {CoIII(μ-O)2CoIII} Complex at Room Temperature (pages 85–89)

      Peter L. Larsen, Terry J. Parolin, Douglas R. Powell, Michael P. Hendrich and A. S. Borovik

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390060

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      Hydrogen bonds to metal complexes located within the active sites of proteins have been implicated in the regulation of function. Incorporation of these noncovalent interactions into a synthetic system with bridging oxo ligands is reported. Unprecedented thermal stability of a complex with a {CoIII(μ-O)2CoIII} core is observed (see picture), in which intramolecular hydrogen bonds to the oxo ligands are present.

    18. Iridium-Catalyzed Mizoroki–Heck-Type Reaction of Organosilicon Reagents (pages 89–92)

      Tooru Koike, Xiaoli Du, Tomoyuki Sanada, Yasuaki Danda and Atsunori Mori

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390061

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      Independent of substrate and solvent, the C[BOND]C bond-forming reaction of organosilicon reagents with α,β-unsaturated carbonyl compounds can be catalyzed by an iridium complex to give exclusively the Mizoroki–Heck-type addition/elimination product (see scheme). This result sharply contrasts the analogous reaction with a rhodium catalyst under similar conditions in which the 1,4-addition product is obtained preferentially. cod=cycloocta-1,5-diene.

    19. Activation of Nitrous Oxide and Selective Oxidation of Alcohols and Alkylarenes Catalyzed by the [PV2Mo10O40]5− Polyoxometalate Ion (pages 92–95)

      Revital Ben-Daniel and Ronny Neumann

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390062

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      A vanadium-substituted polyoxomolybdate ion ([PV2Mo10O40]5−, top right) can activate nitrous oxide to promote the highly selective catalytic oxidation of primary and secondary alcohols to aldehydes and ketones, and the oxidation of various alkylaromatic substrates (see scheme).

    20. Probing Specificity in Carbohydrate–Carbohydrate Interactions with Micelles and Langmuir Monolayers (pages 95–98)

      Paul V. Santacroce and Amit Basu

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390063

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      The epimerization of a single axial hydroxy group in a carbohydrate can affect carbohydrate–carbohydrate interactions significantly. Glycolipid micelles and glycolipid-containing Langmuir monolayers (see picture) were used to model these key interactions on the molecular level. (GM3 is the ganglioside sialosyl-lactosylceramide found on the surface of melanoma cells.)

    21. 1,2-Migration of the Thio Group in Allenyl Sulfides: Efficient Synthesis of 3-Thio-Substituted Furans and Pyrroles (pages 98–101)

      Joseph T. Kim, Alexander V. Kel'in and Vladimir Gevorgyan

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390064

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      The copper-catalyzed cycloisomerization of thioalkynyl ketones 1 a and thioalkynyl imines 1 b allows the efficient synthesis of 3-thio-substituted furans 3 a and pyrroles 3 b, an important class of heterocyclic unit previously inaccessible by standard cycloisomerization techniques. A plausible mechanism for this unusual cascade involves a 1,2-migration of the thio group in the intermediate keto- and iminoallenyl sulfides 2. DMA=N,N-dimethylacetamide.

    22. Synthesis and Characterization of Heterometallic {Cr7M} Wheels (pages 101–105)

      Finn K. Larsen, Eric J. L. McInnes, Hassane El Mkami, Jacob Overgaard, Stergios Piligkos, Gopalan Rajaraman, Eva Rentschler, Andrew A. Smith, Graham M. Smith, Val Boote, Martin Jennings, Grigore A. Timco and Richard E. P. Winpenny

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390034

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      A new set of wheels: Substituting a chromium ion in [Cr8F8(O2CCMe3)16] with one of a number of alternative transition metals has yielded an unprecedented family of heterometallic wheel complexes (see picture), supported at their centers by secondary ammonium ions. Both 3d (Mn, Fe, Co, Ni) and 4d (Cd) metals have been employed to produce such structures, the magnetic and spectroscopic properties of which are discussed.

    23. Novel T-Shaped 14-Electron Platinum(II) Complexes Stabilized by One Agostic Interaction (pages 105–109)

      Walter Baratta, Sergio Stoccoro, Angelino Doppiu, Eberhardt Herdtweck, Antonio Zucca and Pierluigi Rigo

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390035

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      The stereoelectronic properties of the PR2(2,6-Me2C6H3) (R=Ph, Cy) ligand can be used to stabilize an unprecedented class of 14-electron platinum(II) complexes. The X-ray analysis of the cyclometalated cyclohexyl derivative reveals an agostic interaction between the Pt center and an o-methyl moiety (see picture). The fast and reversible formation of three-coordinate platinum–hydrido complexes occurs by reaction with H2, and is achieved through the cleavage of a platinum–carbon bond.

    24. Reversible Formation of Iodosylbenzene–Iron Porphyrin Intermediates in the Reaction of Oxoiron(IV) Porphyrin π-Cation Radicals and Iodobenzene (pages 109–111)

      Wonwoo Nam, Sun Kyung Choi, Mi Hee Lim, Jan-Uwe Rohde, Inwoo Kim, Jinheung Kim, Cheal Kim and Lawrence Que, Jr.

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390036

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      The electronic nature of iron porphyrin complexes and iodobenzene derivatives markedly influences the formation of iodosylbenzene–iron(III) porphyrin intermediates 2, which are generated in the reaction of oxoiron(IV) porphyrin cation radicals 1 and iodobenzene. Epoxidation of olefins by 2 affords high yields of epoxide products.

    25. The Catalytic Intermolecular Orthoarylation of Phenols (pages 112–114)

      Robin B. Bedford, Simon J. Coles, Michael B. Hursthouse and Michael E. Limmert

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390037

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      The use of Wilkinson's catalyst with diisopropylphosphinite ligands acting as cocatalysts allows the catalytic orthoarylation of phenols [Eq. (1)], a process that relies on a C[BOND]H activation of a phenol that has been incorporated into the cocatalyst by transesterification.

    26. η6-Germabenzene Complexes of Chromium and Molybdenum (pages 115–117)

      Norio Nakata, Nobuhiro Takeda and Norihiro Tokitoh

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390038

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      η6-Bonding characteristics are exhibited by stable germabenzene complexes that are stabilized with the extremely bulky 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl ligand. The ring system coordinates to transition-metal centers (M=Cr, Mo; see picture) to give the first evidence of the aromatic character in germabenzene complexes, from the standpoint of their chemical reactivity.

    27. A Diversity-Oriented Synthesis of α-Amino Acid Derivatives by a Silyltelluride-Mediated Radical Coupling Reaction of Imines and Isonitriles (pages 117–120)

      Shigeru Yamago, Hiroshi Miyazoe, Takeyoshi Nakayama, Masaki Miyoshi and Junichi Yoshida

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390039

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      A radical idea: A diversity-oriented synthesis of α-amino acid derivatives is realized by the silyltelluride-mediated radical coupling of imines and isonitriles followed by various transformations of the carbon–tellurium bond of the coupling products (see scheme). The α-amino radical generated from the imine and the silyltelluride is the key intermediate in the coupling reaction.

    28. Preview: Angew. Chem. Int. Ed. 1/2003 (page 127)

      Version of Record online: 14 JAN 2003 | DOI: 10.1002/anie.200390040