Angewandte Chemie International Edition

Cover image for Vol. 42 Issue 48

December 15, 2003

Volume 42, Issue 48

Pages 5909–6157

    1. Cover Picture: DNA Topoisomerase Inhibitor Acutissimin A and Other Flavano-Ellagitannins in Red Wine (Angew. Chem. Int. Ed. 48/2003) (page 5909)

      Stéphane Quideau, Michael Jourdes, Cédric Saucier, Yves Glories, Patrick Pardon and Christian Baudry

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200390630

      Human DNA topoisomerase II is inhibited in vitro by acutissimin A, a flavano-ellagitannin, with an activity much higher than that of the clinically used antitumor drug etoposide. Acutissimin A is formed by a non-enzymatic, yet diastereoselective, condensation reaction occurring during the aging of red wine in oak barrels. S. Quideau et al. report its high-yielding semi-synthesis in their Communication on page 6012 ff.

    2. You have free access to this content
      Ligand and Metal Effects on the Formation of Main-Group Polyhedral Clusters (page 5919)

      Sally R. Boss, Martyn P. Coles, Robert Haigh, Peter B. Hitchcock, Ronald Snaith and Andrew E. H. Wheatley

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200390632

    3. You have free access to this content
    4. Re-Engineering the Genetic Code: Combining Molecular Biology and Organic Chemistry (pages 5926–5928)

      Jan H. van Maarseveen and Jaap Willem Back

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200301698

      Thumbnail image of graphical abstract

      Imagine… if the biomachinery of nature accepted every uncoded amino acid site-specifically as desired. Spectacular advances in breaking the genetic code to expand the set of amino acids available for protein biosynthesis are highlighted, and examples of the post-translational chemical modification of proteins containing these nonnatural amino acids are presented (see scheme).

    5. Carbon Nanotubes by Quantitative Solid-State Conversion of an Organometallic Precursor (pages 5929–5930)

      Marko Burghard

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200301705

      Thumbnail image of graphical abstract

      Optimization of synthesis methods for carbon nanotubes is an essential requirement for realizing their potential applications in field-emission devices, (bio)sensors, or as electrical interconnections in microchips. Procedures directly yielding clean nanotubes from a single molecular precursor (see picture) are highly desired and are expected to provide important clues to the general mechanism of nanotube formation.

    6. The Role of Radicals in Metal-Assisted Oxygenation Reactions (pages 5932–5954)

      Christian Limberg

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200300578

      Thumbnail image of graphical abstract

      A radical view of oxygenation: As revealed by recent research, radical intermediates are almost ubiquitous during metal-assisted oxo-functionalizations of organic substrates (see picture). This review covers examples from the areas as diverse as homogeneous and heterogeneous chemistry, as well as metalloenzyme systems.

    7. N2(SiCl3)4—A Tetrakissilylhydrazine as an Unexpected Product of the Reaction between N2 and SiCl4 (pages 5956–5957)

      Nils Schiefenhövel, Hans-Jörg Himmel and Michael Binnewies

      Version of Record online: 24 NOV 2003 | DOI: 10.1002/anie.200352575

      Thumbnail image of graphical abstract

      Microwave magic: GC–MS analysis and quantum chemical calculations were used to show that N2(SiCl3)4 was a product of the reaction of SiCl4 with N2 activated with a gas plasma generated by microwaves. N2(SiCl3)4 is the first known perhalogenated silyl hydrazine (see scheme: N blue, Si gray, Cl green).

    8. Stereochemically Defined Osmium Centers from Asymmetric Diamination of Olefins: Mechanistic Implications for Osmium-Mediated Acrylate Functionalization (pages 5958–5961)

      Kilian Muñiz, Martin Nieger and Heidi Mansikkamäki

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352244

      Thumbnail image of graphical abstract

      A mechanistic puzzle in the field of osmium(VIII)-mediated functionalization of olefins: How do the diaminations of olefins to give osmaimidazolidines with a stereogenic osmium center proceed (see scheme: C: gray, N: green, red: O, Os: pink)?

    9. Mechanism of the Aliphatic Hydroxylation Mediated by a Bis(μ-oxo)dicopper(III) Complex (pages 5961–5965)

      Philipp Spuhler and Max C. Holthausen

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352231

      Thumbnail image of graphical abstract

      The core of the problem: The selective hydroxylation of benzylic C[BOND]H bonds by a [Cu2O2]2+ core is a nonsynchronous concerted process (see scheme). This is the result of density functional calculations on the mechanistic scenario of the monooxygenase reactivity of a bis(μ-oxo)dicopper(III) complex.

    10. Simple Synthesis of Poly(acetylene) Latex Particles in Aqueous Media (pages 5965–5969)

      Jens O. Krause, M. Tobias Zarka, Udo Anders, Ralf Weberskirch, Oskar Nuyken and Michael R. Buchmeiser

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352637

      Thumbnail image of graphical abstract

      The metathesis catalyst 1 allows the first living cyclopolymerization of 1,6-heptadiynes. With the chiral 4-(ethoxycarbonyl)-4-(1S,2R,5S)-(+)-menthoxycarbonyl-1,6-heptadiyne highly tactic polymers with an alternating cis–trans structure and a stereoregularity of greater than 95 % are obtained. Fixation of 1 on poly(2-oxazoline) block copolymers provides access to poly(acetylene)s under aqueous conditions by micellar catalysis.

    11. Development of a High-Throughput Screen for Protein Catalysts: Application to the Directed Evolution of Antibody Aldolases (pages 5971–5973)

      Jeff Gildersleeve, Alex Varvak, Shane Atwell, Doug Evans and Peter G. Schultz

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352117

      Thumbnail image of graphical abstract

      A semiautomated high-throughput system has been developed to express and purify proteins and assay their catalytic activity. The screen can be used to evolve activity, selectivity, and expression levels of proteins directly or in combination with selections. To illustrate its potential, the system was applied to the directed evolution of catalytic antibodies with aldolase activity.

    12. Fluorinated DNA Bases as Probes of Electrostatic Effects in DNA Base Stacking (pages 5973–5977)

      Jacob S. Lai, Jin Qu and Eric T. Kool

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352531

      Thumbnail image of graphical abstract

      Stacking the deck: A series of aromatic fluorinated nucleosides (the electrostatic surface potentials are depicted) was used to probe electrostatic effects in the stacking of DNA bases in water. Although increasing fluorine substitution (from zero through five) generally increases stacking ability, a new tetrafluorinated analogue is, surprisingly, the strongest helix stabilizer, while the pentafluorinated base is the weakest.

    13. Horseshoes, Rings, and Distorted Rings: Studies of Cyclic Chromium-Fluoride Cages (pages 5978–5981)

      Finn K. Larsen, Jacob Overgaard, Simon Parsons, Eva Rentschler, Andrew A. Smith, Grigore A. Timco and Richard E. P. Winpenny

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352541

      Thumbnail image of graphical abstract

      Running rings around ammonium: Use of amine templates leads to a rich structural chemistry for heterometallic cyclic compounds. For example, use of two diethylammonium cations leads to the formation of the {Cr10Cu2} cage, which is stabilized by N[BOND]H⋅⋅⋅F bonds (see picture). The results suggest a new method for making sophisticated polymetallic architectures.

    14. Anionic Amido N-Heterocyclic Carbenes: Synthesis of Covalently Tethered Lanthanide–Carbene Complexes (pages 5981–5984)

      Polly L. Arnold, Shaheed A. Mungur, Alexander J. Blake and Claire Wilson

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352710

      Thumbnail image of graphical abstract

      Organolanthanides with amido-tethered N-heterocyclic carbenes: a new bidentate ligand that tethers an N-heterocyclic carbene group to a trivalent lanthanide complex (samarium, depicted, N′′=N(SiMe3)2; or yttrium) affords the first organolanthanide amido–carbene complexes and an opportunity to explore the strength and reactivity of the early metal–N-heterocyclic carbene fragment.

    15. High-Throughput Screening by Using a Blue-Fluorescent Antibody Sensor (pages 5984–5987)

      Masayuki Matsushita, Kazuhiro Yoshida, Noboru Yamamoto, Peter Wirsching, Richard A. Lerner and Kim D. Janda

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352793

      Thumbnail image of graphical abstract

      Blue lights the way! The rapid evaluation of enantiomeric excess in the high-throughput screening of libraries has been a hurdle to the discovery of effective catalysts. A blue-fluorescent monoclonal antibody (mAb) addresses this problem; mAb 19G2 is used as a fluorescent sensor (see picture) to evaluate a panel of Cinchona alkaloid derivatives in the synthesis of asymmetric amino acids by phase-transfer catalysis.

    16. Palladium-Catalyzed DYKAT of Vinyl Epoxides: Enantioselective Total Synthesis and Assignment of the Configuration of (+)-Broussonetine G (pages 5987–5990)

      Barry M. Trost, Daniel B. Horne and Michael J. Woltering

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352857

      Thumbnail image of graphical abstract

      A potential general approach to potent N-heterocyclic glycosidase inhibitors is illustrated by the first total synthesis of (+)-broussonetine G (1). The key transformation of the synthesis relies on two successive palladium-catalyzed asymmetric allylic alkylations of butadiene monoxide with a nitrogen nucleophile to construct the pyrrolidine core.

    17. Assembling Metal Clusters with Covalent Linkers: Synthesis and Structure of a Quasi-Planar Pt18 Dendrimer Containing Five Clusters Connected by σ-Alkynyl Spacers (pages 5990–5993)

      Alberto Albinati, Piero Leoni, Lorella Marchetti and Silvia Rizzato

      Version of Record online: 24 NOV 2003 | DOI: 10.1002/anie.200352954

      Thumbnail image of graphical abstract

      Sterically protected tri- and hexanuclear platinum clusters were used as building blocks for the high-yield synthesis of a first-generation dendrimer (see picture; tBu groups are omitted for clarity), which is chemically and thermally stable, and in which the cluster units are separated by conjugated 1,3,5-triethynylphenyl groups.

    18. Efficient Palladium-Catalyzed Coupling of Aryl Chlorides and Tosylates with Terminal Alkynes: Use of a Copper Cocatalyst Inhibits the Reaction (pages 5993–5996)

      Dmitri Gelman and Stephen L. Buchwald

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200353015

      Thumbnail image of graphical abstract

      Less catalyst, lower temperature, and greater generality are the advantages of the new general protocol over those previously described for the palladium-catalyzed coupling of aryl chlorides and alkynes (see scheme). Better results are obtained without a copper cocatalyst, which has been found to inhibit product formation in the coupling reaction of aryl chlorides with terminal alkynes.

    19. A Route to the Thapsigargins from (S)-Carvone Providing a Substrate-Controlled Total Synthesis of Trilobolide, Nortrilobolide, and Thapsivillosin F (pages 5996–6000)

      Steven F. Oliver, Klemens Högenauer, Oliver Simic, Alessandra Antonello, Martin D. Smith and Steven V. Ley

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200353140

      Thumbnail image of graphical abstract

      An entirely substrate-controlled total synthesis of three members of the thapsigargin family (e.g. trilobolide) is achieved starting from (S)-carvone. The synthesis is linear in nature but is achieved in high yield (>90 % per step). The route permits late-stage divergence, providing access to a range of natural products and structural analogues.

    20. Chiral, Porous, Hybrid Solids for Highly Enantioselective Heterogeneous Asymmetric Hydrogenation of β-Keto Esters (pages 6000–6003)

      Aiguo Hu, Helen L. Ngo and Wenbin Lin

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200351264

      Thumbnail image of graphical abstract

      Catalytic building blocks: Chiral porous zirconium phosphonates containing Ru-binap moieties are synthesized by a molecular building-block approach, and characterized by a variety of techniques. These hybrid solids are used for enantioselective heterogeneous asymmetric hydrogenation of β-keto esters with ee values of up to 95 % (see picture). Ready tunability of such a molecular building-block approach promises to lead to useful heterogeneous asymmetric catalysts.

    21. You have free access to this content
      Hepta- and Octacoordinate Boron in Molecular Wheels of Eight- and Nine-Atom Boron Clusters: Observation and Confirmation (pages 6004–6008)

      Hua-Jin Zhai, Anastassia N. Alexandrova, K. Alexander Birch, Alexander I. Boldyrev and Lai-Sheng Wang

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200351874

      Thumbnail image of graphical abstract

      Two types of aromaticity: Experimental and theoretical evidence shows that eight- and nine-atom boron clusters are perfectly planar molecular wheels, with a hepta- or octacoordinated central boron atom, respectively (see picture, B green). The radii of the miniature molecular wheels are found to be 1.8 and 2.0 Å. Analyses of their chemical bonding reveal that they possess double (σ and π) aromaticity, which is responsible for the wheel structures and the extreme coordination environments.

    22. Structurally Defined Catalysts for Enantioselective Oxidative Coupling Reactions (pages 6008–6012)

      Jian Gao, Joseph H. Reibenspies and Arthur E. Martell

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200351978

      Thumbnail image of graphical abstract

      Copper(II)-based complex catalysts (see crystal structures) were prepared and characterized by X-ray crystallography. They were shown to be active catalysts for asymmetric oxidative coupling of 2-naphthol with high enantioselectivity.

    23. You have free access to this content
      DNA Topoisomerase Inhibitor Acutissimin A and Other Flavano-Ellagitannins in Red Wine (pages 6012–6014)

      Stéphane Quideau, Michael Jourdes, Cédric Saucier, Yves Glories, Patrick Pardon and Christian Baudry

      Version of Record online: 11 NOV 2003 | DOI: 10.1002/anie.200352089

      Thumbnail image of graphical abstract

      Good health! Although not initially present in red wine, acutissimin A (see picture) and other flavano-ellagitannins are formed during aging in oak barrels by a diastereoselective nonenzymatic condensation reaction between flavan-3-ols present in grapes and ellagitannin vescalagin from oak. Acutissimin A is a DNA topoisomerase inhibitor that is 250-fold more potent in vitro than the clinically used anicancer drug etoposide.

    24. Multiple Levels of Order in Linked Disc–Rod Liquid Crystals (pages 6015–6018)

      Paul H. J. Kouwer and Georg H. Mehl

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352488

      Thumbnail image of graphical abstract

      In a supermolecular system, the sum of properties is more than that of the individual components. The combination of rod and disc shaped groups (see picture) in the right ratio allows the design of a material with nematic and several layered (smectic) phases. Shape-induced nanophase segregation of rods and discs leads to the formation of distinct sublayers.

    25. A Nanothermometer Based on the Different π Stackings of B- and Z-DNA (pages 6018–6020)

      Ryu Tashiro and Hiroshi Sugiyama

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352752

      Thumbnail image of graphical abstract

      Taking the temperature: The electronic properties of DNA largely depend on the orientation of the π stacking. Based on the discrete clusters of interstrand four-base π stacks in Z-form DNA, a molecular thermometer that exploits the differences in the π stackings of B- and Z-DNA has been designed (see picture).

    26. Intramolecular Cross-Linking of Helical Folds: An Approach to Organic Nanotubes (pages 6021–6024)

      Stefan Hecht and Anzar Khan

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200352983

      Thumbnail image of graphical abstract

      The tubular secondary structure of a folded helical polymer—a poly(m-phenyleneethynylene) derivative carrying multiple cinnamate moieties—is stabilized by intramolecular cross-linking through topochemically controlled photodimerizations (see schematic representation). This approach should enable the generation of organic nanotubes with controlled dimensions and surface functionality that constitute attractive building blocks for functional nanostructures.

    27. Preview: Angew. Chem. Int. Ed. 48/2003 (page 6157)

      Version of Record online: 10 DEC 2003 | DOI: 10.1002/anie.200390634

SEARCH

SEARCH BY CITATION