Angewandte Chemie International Edition

Cover image for Vol. 45 Issue 43

November 6, 2006

Volume 45, Issue 43

Pages 7099–7303

  1. Cover Picture

    1. Top of page
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    3. Graphical Abstract
    4. Web Site
    5. Book Reviews
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    7. Minireview
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    1. Cover Picture: Massively Parallel Dip–Pen Nanolithography with 55 000-Pen Two-Dimensional Arrays (Angew. Chem. Int. Ed. 43/2006) (page 7099)

      Khalid Salaita, Yuhuang Wang, Joseph Fragala, Rafael A. Vega, Chang Liu and Chad A. Mirkin

      Version of Record online: 30 OCT 2006 | DOI: 10.1002/anie.200690148

      Massively parallel dip–pen nanolithography is possible when 55 000 AFM cantilevers are used to write molecules directly onto a surface. An optical micrograph shows the surface after etching (cover picture, left), and each round feature is a miniature image of the face of Thomas Jefferson (AFM image, right), who helped develop the polygraph, a duplicator based on an array of pens. For more information on the new technique see the Communication by C. A. Mirkin and co-workers on page 7220 ff.

  2. Graphical Abstract

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  3. Web Site

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    1. Organic Chemistry Online … and for Free? (page 7114)

      Axel B. Machotta and Martin Oestreich

      Version of Record online: 30 OCT 2006 | DOI: 10.1002/anie.200603935

  4. Book Reviews

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  5. Highlight

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    1. The Twisted Amide 2-Quinuclidone: 60 Years in the Making (pages 7118–7120)

      Jonathan Clayden and Wesley J. Moran

      Version of Record online: 29 SEP 2006 | DOI: 10.1002/anie.200603016

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      No longer left to the imagination: Nonplanar amides have intrigued chemists for decades. This year, a story 60 years in the making came to an end: 2-quinuclidone has finally been synthesized and isolated in the form of its HBF4 salt (see scheme).

  6. Minireview

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    1. You have free access to this content
      Extending the Scope of NMR Spectroscopy with Microcoil Probes (pages 7122–7131)

      Frank C. Schroeder and Matthew Gronquist

      Version of Record online: 22 SEP 2006 | DOI: 10.1002/anie.200601789

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      . ‥ and to cap it off: Capillary NMR (CapNMR) spectroscopy is emerging as a major breakthrough in increasing the mass-sensitivity of NMR spectroscopic analysis. As discussed in the Minireview, not only is the acquisition of the spectra of mass-limited samples getting easier but the quality of CapNMR spectra obtained in many small-molecule applications exceeds what can be accomplished with conventional probe designs.

  7. Review

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    1. Cascade Reactions in Total Synthesis (pages 7134–7186)

      K. C. Nicolaou, David J. Edmonds and Paul G. Bulger

      Version of Record online: 30 OCT 2006 | DOI: 10.1002/anie.200601872

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      Well-orchestrated sequences of events: The virtues of cascade reactions are the focus of this Review, which discusses a number of recent total syntheses that feature these processes, highlights developments in the field, and points to its promising future.

  8. Communications

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    1. Tissue Imaging at Atmospheric Pressure Using Desorption Electrospray Ionization (DESI) Mass Spectrometry (pages 7188–7192)

      Justin M. Wiseman, Demian R. Ifa, Qingyu Song and R. Graham Cooks

      Version of Record online: 26 SEP 2006 | DOI: 10.1002/anie.200602449

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      Images of the masses: Two-dimensional molecular imaging of intact rat brain tissue under ambient conditions was achieved by using the mass spectrometric technique of desorption electrospray ionization (DESI). The distributions of specific lipids, such as sulfatide 24:1, reveal distinctive subanatomical features of the rat brain (cc=corpus callosum; aca=anterior part of anterior commissure) with spatial resolution of less than 500 μm.

    2. A Manganese(III) Complex That Exhibits Spin Crossover Triggered by Geometric Tuning (pages 7192–7195)

      Grace G. Morgan, Kevin D. Murnaghan, Helge Müller-Bunz, Vickie McKee and Charles J. Harding

      Version of Record online: 9 OCT 2006 | DOI: 10.1002/anie.200601823

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      Room to expand: A rare example of thermal spin crossover in a MnIII complex is accompanied by elongation of the bonds to the equatorial N4 donor set upon warming (see scheme; Mn purple, N blue, O red), which is consistent with population of the dmath image orbital. The spin crossover was observed for an N4(O)2 donor set with axial oxygen donors, whereas only a temperature-independent high-spin state was observed with these donors in a cis arrangement.

    3. Nanofibers with Tunable Stiffness from Self-Assembly of an Amphiphilic Wedge–Coil Molecule (pages 7195–7198)

      Jung-Keun Kim, Eunji Lee and Myongsoo Lee

      Version of Record online: 29 SEP 2006 | DOI: 10.1002/anie.200602298

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      Thin end of the wedge: A block molecule, which consists of a rigid wedge-shaped aromatic segment linked at its apex to a flexible poly(ethylene oxide) chain, self-assembles into cylindrical nanofibers in both polar and nonpolar solvents. The structure of the nanofibers changes reversibly in response to solvent polarity, from highly flexible coil-like cylinders in water to stiff rodlike aggregates in n-hexane (see picture).

    4. The Changing Faces of Halogenated Marine Natural Products: Total Synthesis of the Reported Structures of Elatenyne and an Enyne from Laurencia majuscula (pages 7199–7202)

      Helen M. Sheldrake, Craig Jamieson and Jonathan W. Burton

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200602211

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      Knocking them into shape: The total synthesis of two reported marine natural products containing halogenated pyrano[3,2-b]pyrans (see example in blue) has led to the reassignment of both structures as halogenated 2,2′-bifuranyls (red). Concomitantly an efficient route to pyrano[3,2-b]pyrans is described.

    5. Optical Sensors Based on Nanostructured Cage Materials for the Detection of Toxic Metal Ions (pages 7202–7208)

      Tatineni Balaji, Sherif A. El-Safty, Hideyuki Matsunaga, Takaaki Hanaoka and Fujio Mizukami

      Version of Record online: 9 OCT 2006 | DOI: 10.1002/anie.200602453

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      Seeing red: Highly sensitive and selective chemical sensing systems were developed for the naked-eye detection of toxic ions by the direct and indirect postgrafting of hydrophilic and hydrophobic chromophores into spherically nanosized cavities of cubic Fm3m monoliths (HOM-C10). This leads to reliable control over the visual detection of toxic metals such as PbII, CdII, SbIII, and HgII ions at a low concentrations (≈10−9M). DZ= diphenylthiocarbazone.

    6. Corannulene “Hub” Carbon Coordination by [Ru2{O2C(3,5-CF3)2C6H3}2(CO)5] (pages 7208–7210)

      Marina A. Petrukhina, Yulia Sevryugina, Andrey Yu. Rogachev, Edward A. Jackson and Lawrence T. Scott

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200602568

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      Right to the core: A ruthenium(I) complex of corannulene, prepared in a solvent-free environment, exhibits two coordination modes of the bowl: η2-rim and η1-hub (see picture for the hub-coordinated complex; Ru purple, O red, C gray, H white). The latter represents the first example of a transition-metal center binding only to the fullerene-like interior of an open geodesic polyarene.

    7. Noncrystalline Metal–Boron Nanotubes: Synthesis, Characterization, and Catalytic-Hydrogenation Properties (pages 7211–7214)

      Yan Zhu, Fuping Liu, Weiping Ding, Xuefeng Guo and Yi Chen

      Version of Record online: 9 OCT 2006 | DOI: 10.1002/anie.200602610

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      It's all in the mix: A mixed-surfactant-templated synthesis gives noncrystalline metal–boron nanotubes (see picture: TEM image of Fe–B nanotubes; inset: the corresponding selected-area electron diffraction pattern) from simple starting materials under mild conditions. These nanotubes show better catalytic activity for the hydrogenation of m-nitrotoluene to m-toluidine than the corresponding nanoparticles.

    8. Halogen-Bridged PtII/PtIV Mixed-Valence Ladder Compounds (pages 7214–7217)

      Daisuke Kawakami, Masahiro Yamashita, Satoshi Matsunaga, Shinya Takaishi, Takashi Kajiwara, Hitoshi Miyasaka, Ken-ichi Sugiura, Hiroyuki Matsuzaki, Hiroshi Okamoto, Yusuke Wakabayashi and Hiroshi Sawa

      Version of Record online: 9 OCT 2006 | DOI: 10.1002/anie.200602987

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      Chutes and … Ladders in coordination networks represent a boundary between 1D and 2D systems. Halogen-bridged PtII/PtIV mixed-valence ladder compounds have been synthesized for the first time. In these compounds, the band gap is controlled by changing the bridging halide ions. Moreover, by changing counteranions, the charge arrangements of the ladder compounds can be controlled.

    9. A Heterogeneous Silica-Supported Scandium/Ionic Liquid Catalyst System for Organic Reactions in Water (pages 7217–7220)

      Yanlong Gu, Chikako Ogawa, Juta Kobayashi, Yuichiro Mori and Shū Kobayashi

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200603070

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      Several carbon–carbon bond-forming reactions are catalyzed by a silica-supported scandium triflate catalyst combined with an ionic liquid. The combination of these two components creates a hydrophobic reaction environment in water (see scheme; blue: water, yellow: substrate, orange: ionic liquid).

    10. Massively Parallel Dip–Pen Nanolithography with 55 000-Pen Two-Dimensional Arrays (pages 7220–7223)

      Khalid Salaita, Yuhuang Wang, Joseph Fragala, Rafael A. Vega, Chang Liu and Chad A. Mirkin

      Version of Record online: 25 SEP 2006 | DOI: 10.1002/anie.200603142

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      Lots of writing on the wall: A simple and flexible approach for performing high-throughput, large-area, direct-write molecular patterning, without tip feedback, is demonstrated by using a 55 000-pen two-dimensional array of atomic force microscope (AFM) cantilevers. The use of low-aspect-ratio pyramidal tips, curved cantilevers, and a novel gravity-driven alignment method allows parallel patterning of molecules across 1-cm2 substrate areas at sub-100-nm resolution.

    11. Photochemical Synthesis of R-Shaped DNA toward DNA Recombination and Processing In Vitro (pages 7223–7226)

      Masayuki Ogino and Kenzo Fujimoto

      Version of Record online: 29 SEP 2006 | DOI: 10.1002/anie.200603161

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      Rewriting the end: Two unmodified oligodeoxyribonucleotides (ODNs) were photochemically ligated through modification of ODNs that contain photosensitive nucleosides at both terminal ends in the presence of a template ODN. Additionally, this method was applied to the synthesis of R-shaped DNA as a unique structure.

    12. Dynamic Motion of Building Blocks in Porous Coordination Polymers (pages 7226–7230)

      Satoshi Horike, Ryotaro Matsuda, Daisuke Tanaka, Seijiro Matsubara, Motohiro Mizuno, Kazunaka Endo and Susumu Kitagawa

      Version of Record online: 2 OCT 2006 | DOI: 10.1002/anie.200603196

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      Controlling guests: Porous coordination polymers containing mobile organic groups, such as naphthalene rings (see picture), are synthesized, and their rotational motion is characterized by solid-state 2H NMR spectroscopy. The rotation of the groups can be switched off (blue) by guest (blue spheres) adsorption and switched on (yellow) again by guest desorption.

    13. A Highly Efficient and Practical Method for Catalytic Asymmetric Vinylogous Mannich (AVM) Reactions (pages 7230–7233)

      Emma L. Carswell, Marc L. Snapper and Amir H. Hoveyda

      Version of Record online: 16 OCT 2006 | DOI: 10.1002/anie.200603496

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      Very selective but very easy: These are two of the attributes of the asymmetric vinylogous Mannich reactions presented herein. These reactions can be run on a gram scale and in undistilled THF and air (see scheme; TMS=SiMe3). All that is needed is commercially available AgOAc, a readily available amino acid derived phosphine, and a commercially available or easily prepared (one step) siloxyfuran.

    14. Na2Li8[(UO2)11O12(WO5)2]: Three Different Uranyl-Ion Coordination Geometries and Cation–Cation Interactions (pages 7233–7235)

      Evgeny V. Alekseev, Sergey V. Krivovichev, Wulf Depmeier, Oleg I. Siidra, Karsten Knorr, Evgeny V. Suleimanov and Evgeny V. Chuprunov

      Version of Record online: 15 SEP 2006 | DOI: 10.1002/anie.200601207

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      Uranyl interactions: The title compound is the first example of an actinide compound that contains three different actinyl-ion coordination geometries, namely, octahedral, pentagonal bipyramidal, and hexagonal bipyramidal. Strong cation–cation interactions between the uranyl ions lead to pentamers with a rather unusual configuration (see picture; U dark gray, O light gray).

    15. Total Synthesis of Tubulysin U and V (pages 7235–7239)

      Alexander Dömling, Barbara Beck, Uwe Eichelberger, Sukumar Sakamuri, Sanjay Menon, Quin-Zene Chen, Yingchun Lu and Ludger A. Wessjohann

      Version of Record online: 2 OCT 2006 | DOI: 10.1002/anie.200601259

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      Multicomponent method: Tubulysins are among the most potent cytotoxic agents known. Now the first total synthesis of some members has been achieved by utilizing a rapid three-component reaction for the synthesis of the unusual central thiazole amino acid tubuvaline (see scheme; Boc=tert-butoxycarbonyl, Ac=acetyl), thereby opening new perspectives for anticancer drug development.

      Corrected by:

      Corrigendum: Total Synthesis of Tubulysin U and V

      Vol. 46, Issue 14, 2347–2348, Version of Record online: 16 MAR 2007

    16. Bioenabled Synthesis of Rutile (TiO2) at Ambient Temperature and Neutral pH (pages 7239–7243)

      Nils Kröger, Matthew B. Dickerson, Gul Ahmad, Ye Cai, Michael S. Haluska, Kenneth H. Sandhage, Nicole Poulsen and Vonda C. Sheppard

      Version of Record online: 29 SEP 2006 | DOI: 10.1002/anie.200601871

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      Biomineral-forming organisms provide inspiration for developing new reaction pathways to functional materials, such as rutile for optical devices. A recombinant protein (rSilC) was designed based on the sequence of a silica-forming protein from a diatom. This unique protein induced the formation of hierarchically nanostructured rutile microcrystals under mild reaction conditions (see SEM image).

    17. Hormone–PAMAM Dendrimer Conjugates: Polymer Dynamics and Tether Structure Affect Ligand Access to Receptors (pages 7243–7248)

      Sung Hoon Kim and John A. Katzenellenbogen

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200601923

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      An open and closed case: Estradiol was conjugated to a PAMAM dendrimer (gray circle) through a short (17α-phenylethynyl) or a long (hexaethyleneglycol) tether to evaluate how ligand access to a receptor is affected. With the short tether (a), the hormone is free and solvent exposed, with unimpeded access to the estrogen receptor, while the long tether (b) wraps around the hormone and the dendrimer and markedly reduces access to the receptor.

    18. Taming a Functional Group: Creating Air-Stable, Chiral Primary Phosphanes (pages 7248–7251)

      Rachel M. Hiney, Lee J. Higham, Helge Müller-Bunz and Declan G. Gilheany

      Version of Record online: 5 OCT 2006 | DOI: 10.1002/anie.200602143

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      No rings of fire! Enantiopure primary phosphanes have been developed which are remarkably stable to air oxidation in both solid and solution states (see example). This new class of stable ligand synthon appears to owe its stability to conjugation in their aryl backbones with the extended π ring system. Even one extra ring is good enough.

    19. On the Species Involved in the Vaporization of Imidazolium Ionic Liquids in a Steam-Distillation-Like Process (pages 7251–7254)

      Brenno A. DaSilveira Neto, Leonardo S. Santos, Fabiane M. Nachtigall, Marcos N. Eberlin and Jairton Dupont

      Version of Record online: 9 OCT 2006 | DOI: 10.1002/anie.200602219

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      Steaming ahead: The nonvolatility of ionic liquids is challenged further. Imidazolium(Im)-based ionic liquids composed of supramolecular structures in the condensed phase (see scheme) vaporize at ambient pressure from heated (100–600 °C) solvent droplets as neutral clusters of the type ImnAn.

    20. An Engineered Linker Capable of Promoting On-Resin Reactions for Microwave-Assisted Solid-Phase Organic Synthesis (pages 7255–7258)

      Li-Ping Sun and Wei-Min Dai

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200602523

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      An active link: A diglycine-containing linker (cat⋅linker) was fabricated on Rink amide resin for dual functions: a) attachment of a scaffold and b) capture of metal ions for promoting on-resin reactions (see picture). The metal-catching feature of the linker proves essential for the solid-phase synthesis of indoles through microwave-assisted CuII-mediated heteroannulation.

    21. Synthesis of the C31–C67 Fragment of Amphidinol 3 (pages 7258–7262)

      Javier de Vicente, John R. Huckins and Scott D. Rychnovsky

      Version of Record online: 2 OCT 2006 | DOI: 10.1002/anie.200602742

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      A tetrahydropyran intermediate, prepared from (−)-diethyl tartrate, was used to assemble the C31–C67 fragment of amphidinol 3. Both of the tetrahydropyran rings in the natural product were prepared from this intermediate. The polyene segment was assembled with high selectivity.

    22. Polyazidopyrimidines: High-Energy Compounds and Precursors to Carbon Nanotubes (pages 7262–7265)

      Chengfeng Ye, Haixiang Gao, Jerry A. Boatz, Gregory W. Drake, Brendan Twamley and Jean'ne M. Shreeve

      Version of Record online: 13 SEP 2006 | DOI: 10.1002/anie.200602778

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      An additional azidomethyl group dramatically decreases the melting points of the corresponding azidopyrimidines. Theoretical calculations show that these polyazido compounds (see picture; N light blue, C dark blue, H white) exhibit highly promising energetic properties. 2,4,6-Triazidopyrimidine was found to be a novel precursor to carbon nanotubes in the presence of Ni(ClO4)2.

    23. Crystallographic Characterization of Difluoropropargyl Indium Bromide, a Reactive Fluoroorganometallic Reagent (pages 7265–7267)

      Bo Xu, Mark S. Mashuta and Gerald B. Hammond

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200602823

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      Elusive intermediate trapped: γ-Substituted difluoropropargyl groups can stabilize an organoindium(III) complex. The resulting structure is the only known example of an indium atom bonded to a propargylic carbon atom (see picture; F blue, S yellow, C white, H green). Reactions with electrophiles produced a difluoroalkyne or -allene, depending on the type of electrophile.

    24. Towards Homoleptic Naphthalenemetalates of the Later Transition Metals: Isolation and Characterization of Naphthalenecobaltates(1−) (pages 7268–7271)

      William W. Brennessel, Victor G. Young Jr. and John E. Ellis

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200602937

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      Taming of the wild anions: Highly labile naphthalene complexes of formally negative-valent later transition metals have been obtained in the form of [Co(η4-C10H8)(η4-cod)] (see picture; cod=1,5-cyclooctadiene) and [Co(η4-C10H8)2]. The latter is the first structurally authenticated homoleptic bis(naphthalene)metal anion for any d-block element and promises to be a particularly reactive synthon for the “naked” atomic cobalt anion.

    25. Ambient-Temperature Living Anionic Polymerization of Phosphaalkenes: Homopolymers and Block Copolymers with Controlled Chain Lengths (pages 7271–7274)

      Kevin J. T. Noonan and Derek P. Gates

      Version of Record online: 29 SEP 2006 | DOI: 10.1002/anie.200602955

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      New kid on the block: Unprecedented polystyrene-block-poly(methylenephosphine) copolymers are accessible from the reaction of living polystyrene with the phosphaalkene (see scheme; Mes=2,4,6-Me3C6H2). The living anionic polymerization of P[DOUBLE BOND]C bonds represents a new development in phosphorus chemistry and opens up the possibility to synthesize functional phosphorus polymers of controlled architectures.

    26. Selective Formation of Polycarbonate over Cyclic Carbonate: Copolymerization of Epoxides with Carbon Dioxide Catalyzed by a Cobalt(III) Complex with a Piperidinium End-Capping Arm (pages 7274–7277)

      Koji Nakano, Toshihiro Kamada and Kyoko Nozaki

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200603132

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      Sidestepping a cyclic side product: Copolymerization of terminal epoxides with CO2 was investigated by using a cobalt(III) complex bearing a piperidinium end-capping arm and a piperidinyl arm (see scheme; DME=1,2-dimethoxyethane). The catalyst system can selectively produce copolymers without contaminant formation of cyclic carbonates even at high conversion of the epoxide (>99 %).

    27. Efficient Preparation and Catalytic Activity of MgO(111) Nanosheets (pages 7277–7281)

      Kake Zhu, Juncheng Hu, Christian Kübel and Ryan Richards

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200602393

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      Preferential growth of MgO(111) nanosheets with a thickness typically between 3 and 5 nm (see TEM image) has been achieved by a simple, efficient, and inexpensive wet chemical route. The MgO(111) nanosheets have been shown to have ultrahigh activity for the Claisen–Schmidt condensation of benzaldehyde and acetophenone.

    28. NMR Spectroscopy of Laser-Polarized 129Xe Under Continuous Flow: A Method To Study Aqueous Solutions of Biomolecules (pages 7282–7284)

      Daniela Baumer, Eike Brunner, Peter Blümler, Paul Philipp Zänker and Hans Wolfgang Spiess

      Version of Record online: 2 OCT 2006 | DOI: 10.1002/anie.200601008

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      Go with the flow: In many applications of NMR spectroscopy in chemistry, proper sample preparation is absolutely critical for success, in particular in biochemical and biomedical areas. For the NMR spectroscopy of laser-polarized 129Xe, an efficient and robust method for continuous flow of the gas to a NMR tube was developed. Applications to H2O, DMSO, phospholipid bicelles, and 2D exchange NMR spectroscopy are demonstrated.

    29. Cycloisomerization of 1,6-Dienes Mediated by Lewis Super Acids without Additives: Easy Access to Polysubstituted Six-Membered Carbocycles (pages 7285–7289)

      Fanny Grau, Andreas Heumann and Elisabet Duñach

      Version of Record online: 6 OCT 2006 | DOI: 10.1002/anie.200602020

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      The tin salt Sn(NTf2)4 (Tf=trifluoromethanesulfonyl) is an efficient catalyst for the selective and ring-size-specific cycloisomerization of highly substituted 1,6-dienes to give six-membered-ring carbocycles (see scheme; X=C(CO2Et)2, C(CO2Me)2 C(CN)(CO2Et), etc.). This is the first Lewis acid catalyzed cycloisomerization of this type of substrate.

    30. Aqueous-Phase Hydroformylation of 1-Octene: Styrene Latices as Phase-Transfer Agents (pages 7289–7292)

      Katharina Kunna, Christian Müller, Joachim Loos and Dieter Vogt

      Version of Record online: 9 OCT 2006 | DOI: 10.1002/anie.200602386

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      An elegant method for the aqueous-phase hydroformylation of 1-octene with a water-soluble Rh catalyst and amphiphilic latex particles as phase-transfer agents has been developed (see scheme). In this way, substantial concentrations of the olefin in the aqueous catalyst-containing phase were reached, and thus reasonable turnover frequencies under mild reaction conditions could be achieved.

    31. Proton Magnetic Shielding Tensors in Benzene—From the Individual Molecule to the Crystal (pages 7292–7295)

      Thomas Heine, Clémence Corminboeuf, Gisbert Grossmann and Ulrich Haeberlen

      Version of Record online: 20 SEP 2006 | DOI: 10.1002/anie.200601557

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      Inequivalent in the crystal: The three chemically distinct calculated proton shielding tensors of solid benzene—a consequence of interactions in the crystal—can be described as the superposition of the isolated molecule and the intermolecular shielding contributions. In the ovaloid representations of the shielding tensors 1, 2, and 3 indicate the least, intermediate, and most shielded principal axes, respectively.

    32. Bridging Rotaxanes' Wheels—Cyclochiral Bonnanes (pages 7296–7299)

      Motkuri Radha Kishan, Amir Parham, Frauke Schelhase, Albena Yoneva, Gabriele Silva, Xiaoming Chen, Yoshio Okamoto and Fritz Vögtle

      Version of Record online: 9 OCT 2006 | DOI: 10.1002/anie.200602002

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      Building bridges: The wheels of [3]rotaxane were intramolecularly tethered to yield the first member of cyclochiral, interlocked architectures named “bonnanes” (after the city Bonn, Germany; see scheme). The enantiomers and meso form were separated on an immobilized chiral phase and characterized.

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