Chemistry - A European Journal

Cover image for Vol. 18 Issue 31

July 27, 2012

Volume 18, Issue 31

Pages 9433–9735

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
    9. Full Papers
    10. Preview
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      Cover Picture: C[BOND]H Activation: A Complementary Tool in the Total Synthesis of Complex Natural Products (Chem. Eur. J. 31/2012) (page 9433)

      Prof. Dr. David Y.-K. Chen and Prof. Dr. So Won Youn

      Version of Record online: 20 JUL 2012 | DOI: 10.1002/chem.201290130

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      Transition-metal-mediated C[BOND]H activationis reshaping the synthetic field and gradually infusing a “C[BOND]H activation mind-set” in both students and practitioners of synthetic organic chemistry. Naturally, applications of this powerful synthetic tool in the context of complex molecular architectures are beginning to blossom. In this Review by D. Y.-K. Chen and S. W. Youn on page 9452 ff., recently completed total syntheses of natural products showcasing the ingenious synthetic designs mindful of “C[BOND]H activation” and “non-C[BOND]H activation” tactics are presented, highlighting the complementary and indispensable roles of both strategies.

  2. Inside Cover

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
    9. Full Papers
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    1. Inside Cover: A New Class of Amphiphiles Bearing Rigid Hydrophobic Groups for Solubilization and Stabilization of Membrane Proteins (Chem. Eur. J. 31/2012) (page 9434)

      Prof. Pil Seok Chae, Prof. Søren G. F. Rasmussen, Rohini R. Rana, Kamil Gotfryd, Andrew C. Kruse, Aashish Manglik, Kyung Ho Cho, Shailika Nurva, Prof. Ulrik Gether, Prof. Lan Guan, Prof. Claus J. Loland, Dr. Bernadette Byrne, Prof. Brian K. Kobilka and Prof. Samuel H. Gellman

      Version of Record online: 20 JUL 2012 | DOI: 10.1002/chem.201290131

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      A class of structurally new amphiphile based on steroidal lipophilic groups have been prepared by P. S. Chae et al. on page 9485 ff. The results show that the new amphiphiles confer enhanced stability to a variety of membrane proteins in solution relative to popular conventional detergent dodecylmaltoside (DDM). The potential of the new amphiphiles as tools for solubilization, isolation, and stabilization is evident from their success with a variety of membrane proteins.

  3. Graphical Abstract

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
    9. Full Papers
    10. Preview
  4. Corrigendum

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
    9. Full Papers
    10. Preview
    1. You have free access to this content
  5. News

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
    9. Full Papers
    10. Preview
  6. Review

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
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    1. C[BOND]H Activation

      C[BOND]H Activation: A Complementary Tool in the Total Synthesis of Complex Natural Products (pages 9452–9474)

      Prof. Dr. David Y.-K. Chen and Prof. Dr. So Won Youn

      Version of Record online: 26 JUN 2012 | DOI: 10.1002/chem.201201329

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      The total synthesis of natural products has been carried out showcasing the creative and ingenious application of C[BOND]H activation in the construction of complex molecular architectures that are compared with their “non-C[BOND]H activation” counterparts. These accomplishments stood as true testaments of the growing potential of C[BOND]H activation, and further cementing the power of this emerging synthetic technology (see figure).

  7. Communications

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
    9. Full Papers
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    1. Hydrides

      Hydride–Hydride Bonding Interactions in the Hydrogen Storage Materials AlH3, MgH2, and NaAlH4 (pages 9476–9480)

      Dr. Peter Sirsch, Franklin N. Che, James T. Titah and Prof. Dr. G. Sean McGrady

      Version of Record online: 22 JUN 2012 | DOI: 10.1002/chem.201200803

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      Force of attraction: The structures and electron distribution of the hydrogen storage materials AlH3, MgH2, and NaAlH4 were explored in detail. Topological analysis of DFT-computed electron densities revealed a plethora of stabilizing interactions between negatively charged hydrogen atoms in these and other hydrides of light metals (see diagram), some of which are remarkably strong and might play a role in the desorption of hydrogen.

    2. Fluorescent Probes

      Ratiometric Fluorescent Signaling of Small Molecule, Environmentally Sensitive Dye Conjugates for Detecting Single-Base Mutations in DNA (pages 9481–9484)

      Chun-xia Wang, Dr. Yusuke Sato, Megumi Kudo, Dr. Seiichi Nishizawa and Prof. Dr. Norio Teramae

      Version of Record online: 25 JUN 2012 | DOI: 10.1002/chem.201200219

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      Bind it! A ratiometric fluorescent probe based on conjugation of a DNA-binding ligand with an environmentally sensitive dye to probe hydrophobic grooves of the DNA helix was developed. The resulting conjugate ATMND–DBD can bind to an orphan nucleobase opposite an abasic (AP) site with high selectivity and affinity for pyrimidine bases (see figure).

    3. Amphiphiles

      A New Class of Amphiphiles Bearing Rigid Hydrophobic Groups for Solubilization and Stabilization of Membrane Proteins (pages 9485–9490)

      Prof. Pil Seok Chae, Prof. Søren G. F. Rasmussen, Rohini R. Rana, Kamil Gotfryd, Andrew C. Kruse, Aashish Manglik, Kyung Ho Cho, Shailika Nurva, Prof. Ulrik Gether, Prof. Lan Guan, Prof. Claus J. Loland, Dr. Bernadette Byrne, Prof. Brian K. Kobilka and Prof. Samuel H. Gellman

      Version of Record online: 22 JUN 2012 | DOI: 10.1002/chem.201200069

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      Non-traditional amphiphiles: Conferring aqueous solubility on membrane proteins generally requires the use of a detergent or other amphiphilic agent. A new class of amphiphiles was synthesized, based on steroidal lipophilic groups, and evaluated with several membrane proteins. The results show that the new amphiphile, “glyco-diosgenin” (GDN; see figure), confers enhanced stability to a variety of membrane proteins in solution relative to popular conventional detergents, such as dodecylmaltoside (DDM).

      Corrected by:

      Corrigendum: Corrigendum: A New Class of Amphiphiles Bearing Rigid Hydrophobic Groups for Solubilization and Stabilization of Membrane Proteins

      Vol. 19, Issue 16, 4964, Version of Record online: 8 APR 2013

    4. Enantioselective Synthesis

      Catalytic and Enantioselective α-Functionalization of Oxindoles Through Oxidative Reactions with Naphthoquinones (pages 9491–9495)

      Woon-Yew Siau, Wenjun Li, Fei Xue, Qiao Ren, Prof. Minghu Wu, Prof. Shaofa Sun, Prof. Haibing Guo, Prof. Xuefeng Jiang and Prof. Dr. Jian Wang

      Version of Record online: 26 JUN 2012 | DOI: 10.1002/chem.201200206

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      Strong as an oxindole: The enantioselective assembly of 3,3-disubstituted oxindoles is an attractive and valuable target because of the unique properties of the oxindole core. A new organocatalyzed and enantioselective aerobic oxidative strategy for the assembly of this core structure from oxindoles and simple naphthoquinones is reported (see scheme).

    5. Asymmetric Catalysis

      Enantioselective Tandem Reactions at Elevated Temperatures: One-Pot Hydroformylation/SN1 Alkylation (pages 9496–9499)

      Dr. Julian Stiller, Andreas J. Vorholt, Karoline A. Ostrowski, Prof. Arno Behr and Prof. Mathias Christmann

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201200639

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      Canned heat: The optimization of a tandem sequence of a metal-catalyzed and a subsequent organocatalytic reaction is described (see figure). The tandem sequence was initially optimized toward a high yield by variations of substrate ratio, rhodium precursor, and ligands. The tandem reaction is also extendable to more complex alkenes and to substrates with additional functional groups.

      Corrected by:

      Corrigendum: Corrigendum: Enantioselective Tandem Reactions at Elevated Temperatures: One-Pot Hydroformylation/SN1 Alkylation

      Vol. 18, Issue 35, 10780, Version of Record online: 17 AUG 2012

    6. Silylation

      Zinc-Catalyzed Dehydrogenative N-Silylation of Indoles with Hydrosilanes (pages 9500–9504)

      Prof. Dr. Teruhisa Tsuchimoto, Yoshihiko Iketani and Masaru Sekine

      Version of Record online: 26 JUN 2012 | DOI: 10.1002/chem.201200651

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      Zinc catalysis: Zinc triflate in a nitrile solvent behaved as an effective catalyst for dehydrogenative N-silylation with a variety of indoles and hydrosilanes (see scheme). The addition of pyridine greatly accelerated the N-silylation reaction to produce N-silylindoles exclusively in high to excellent yields.

    7. Nanostructures

      Simplifying the Creation of Dumbbell-Like Cu-Ag Nanostructures and Their Enhanced Catalytic Activity (pages 9505–9510)

      Xiaoqing Huang, Yujing Li, Hailong Zhou, Xing Zhong, Prof. Xiangfeng Duan and Prof. Yu Huang

      Version of Record online: 27 JUN 2012 | DOI: 10.1002/chem.201200817

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      Joined at the hip: A one-pot synthesis strategy for the dumbbell-like Cu-Ag nanostructures (see picture) was developed. A broad range of compositions and sizes were readily tuned for these dumbbell-like Cu-Ag nanostructures. Owing to their unique structures, the Cu-Ag nanostructures exhibit enhanced catalytic activity in the hydrogenation of 4-nitrophenol, and are expected to enable other advanced catalysis applications.

    8. C[BOND]H Functionalization

      Brønsted Acid Enhanced Rhodium-Catalyzed Conjugate Addition of Aryl C[BOND]H Bonds to α,β-Unsaturated Ketones under Mild Conditions (pages 9511–9515)

      Dr. Lei Yang, Bo Qian and Prof. Dr. Hanmin Huang

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201201348

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      Acid test: With a Brønsted acid as the solvent, the rhodium-catalyzed direct addition of aryl C[BOND]H bonds to α,β-unsaturated ketones was realized under mild reaction conditions (see scheme). The acid may assist by interceding in the conflict of the two proton-transfer events and averting the substrate inhibition involved in this type of C[BOND]H addition reaction.

    9. Hybrid Peptides

      Unprecedented Torsional Preferences in trans2,3-Amino Acid Residues and Formation of 11-Helices in α,β2,3-Hybrid Peptides (pages 9516–9520)

      Dhayalan Balamurugan and Dr. Kannoth M. Muraleedharan

      Version of Record online: 26 JUN 2012 | DOI: 10.1002/chem.201201415

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      Anti or gauche? trans2,3-Amino acid residues that are known to promote extended structures in their peptides show specific rotamer preferences in response to an intramolecular hydrogen-bonding possibility, which facilitates the 11-helical structures in their 1:1 α,β-hybrid peptides (see figure). Preferences for the gauche conformation for all internal β residues and anti for the C-terminal residue in these peptides were confirmed by NMR spectroscopic and X-ray diffraction experiments.

    10. Nanostructures

      Formation of Highly Ordered Nanochannel Nb Oxide by Self-Organizing Anodization (pages 9521–9524)

      Kiyoung Lee, Dr. Yang Yang, Dr. Min Yang and Prof. Dr. Patrik Schmuki

      Version of Record online: 25 JUN 2012 | DOI: 10.1002/chem.201201426

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      Supercapacitor: A highly aligned nanochannel Nb oxide structure can be formed by self-organizing anodization of Nb in a K2HPO4-containing glycerol electrolyte at elevated temperatures (180 °C). Under optimized electrochemical conditions, a high degree of ordering can be achieved. These layers can be used as supercapacitors (see figure).

    11. Transfer Hydrogenation

      The Remarkable Effect of a Simple Ion: Iodide-Promoted Transfer Hydrogenation of Heteroaromatics (pages 9525–9529)

      Jianjun Wu, Dr. Chao Wang, Dr. Weijun Tang, Dr. Alan Pettman and Prof. Jianliang Xiao

      Version of Record online: 26 JUN 2012 | DOI: 10.1002/chem.201201517

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      I can do it! Accelerated by simple iodide ions, rhodium-catalysed transfer hydrogenation can be readily performed on quinolines, isoquinolines and quinoxalines, affording the tetrahydro products in high yields with low catalyst loading (see scheme).

    12. Coordination Chemistry

      Double Activation of an N-Alkylimidazole (pages 9530–9533)

      Miguel A. Huertos, Dr. Julio Pérez and Dr. Lucía Riera

      Version of Record online: 27 JUN 2012 | DOI: 10.1002/chem.201201603

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      Make it a double! A coordinated N-methylimidazole has been transformed, by double activation, into a bridging ligand that is simultaneously an abnormal N-heterocyclic carbene (NHC) and a Fischer carbene.

  8. Full Papers

    1. Top of page
    2. Cover Picture
    3. Inside Cover
    4. Graphical Abstract
    5. Corrigendum
    6. News
    7. Review
    8. Communications
    9. Full Papers
    10. Preview
    1. Molecular Magnets

      Enhanced Magnetic Hardness in a Nanoscale Metal–Organic Hybrid Ferrimagnet (pages 9534–9542)

      Dr. Li-Rong Guo, Dr. Song-Song Bao, Prof. Dr. Bin Liu, Dai Zeng, Jie Zhao, Prof. Dr. Jun Du and Prof. Dr. Li-Min Zheng

      Version of Record online: 26 JUN 2012 | DOI: 10.1002/chem.201201124

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      Size-dependent magnetism: By reducing the particle size to the nanoscale region, [Co33-OH)2(BTP)2] (1; BTP=4-(3-bromothienyl)phosphonate, Tc=30.5 K) can, at low temperature, transform from a soft magnet to one of the hardest molecule-based magnets know to date (see figure; MP=microparticle, NP=nanoparticle).

    2. Arenes

      Enantiotropic Nematics From Cross-Like 1,2,4,5-Tetrakis(4′-alkyl-4-ethynylbiphenyl)benzenes and Their Biaxiality Studies (pages 9543–9551)

      Dr. Hsiu-Hui Chen, Hsing-An Lin, Yin-Hui Lai, Shu-Yu Lin, Chien-Hung Chiang, Prof. Hsiu-Fu Hsu, Prof. Tzenge-Lien Shih, Dr. Jey-Jau Lee, Prof. Chien-Chen Lai and Ting-Shen Kuo

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201103453

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      Take up your cross: An enantiotropic nematic phase with a wide temperature range has been achieved by using cross-like mesogens. Biaxiality investigations by using conoscopic and 2D XRD studies imply the formation of small smectic C-like meta-cybotactic clusters in the nematic arrangement.

    3. Fluorophores

      Environment-Sensitive Fluorophores with Benzothiadiazole and Benzoselenadiazole Structures as Candidate Components of a Fluorescent Polymeric Thermometer (pages 9552–9563)

      Dr. Seiichi Uchiyama, Kohki Kimura, Chie Gota, Dr. Kohki Okabe, Kyoko Kawamoto, Dr. Noriko Inada, Dr. Toshitada Yoshihara and Prof. Seiji Tobita

      Version of Record online: 3 JUL 2012 | DOI: 10.1002/chem.201200597

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      Sensitive fluorophores: Two new environment-sensitive fluorophores, DBThD-IA and DBSeD-IA (see figure), are reported. Their photophysical and photochemical properties have been investigated by UV/Vis absorption, fluorescence, and phosphorescence spectroscopy, analysis of the fluorescence lifetimes and optoacoustic signals, and by performing photolysis experiments. DBThD-IA has successfully been used to develop a photostable fluorescent nanogel thermometer.

    4. Cross-Coupling Reactions

      Rapid and Efficient Access to Secondary Arylmethylamines (pages 9564–9570)

      Dr. Nicolas Fleury-Brégeot, Dr. Jessica Raushel, Dr. Deidre L. Sandrock, Dr. Spencer D. Dreher and Prof. Gary A. Molander

      Version of Record online: 5 JUL 2012 | DOI: 10.1002/chem.201200831

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      Secondary ammoniomethyltrifluoroborates can be easily synthesized by nucleophilic substitution on potassium bromomethyltrifluoroborate. These reagents have then been used in Suzuki–Miyaura cross-couplings with aryl bromides, offering an effective access to the aminomethylarene structural motif. This new method provides an interesting alternative to the reductive amination procedure (see scheme).

    5. Cage Compounds

      A Series of Trifacial Pd6 Molecular Barrels with Porphyrin Walls (pages 9571–9579)

      Arun Kumar Bar, Sudip Mohapatra, Prof. Ennio Zangrando and Prof. Partha Sarathi Mukherjee

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201201077

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      Like shooting fish in a barrel: Three nanoscopic trifacial Pd6 molecular barrels with porphyrin walls were characterized by spectroscopy and X-ray diffraction. These water-soluble barrels bound ZnII ions in the N4 pockets of the porphyrin walls.

    6. Ionic Liquids

      Lanthanoid-Based Ionic Liquids Incorporating the Dicyanonitrosomethanide Anion (pages 9580–9589)

      Dr. Anthony S. R. Chesman, Mei Yang, Nicolas D. Spiccia, Prof. Dr. Dr. Glen B. Deacon, Prof. Dr. Stuart R. Batten and Prof. Dr. Anja-Verena Mudring

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201103379

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      New lanthanoid-based ionic liquids containing the dicyanonitrosomethanide (dcnm) anion were synthesised (see figure). A facile synthetic procedure was employed to combine the [Ln(dcnm)6]3− trianion with imidazolium, pyridinium and ammonium-based cations.

    7. Click Chemistry

      A Nucleobase-Discriminating Pyrrolo-dC Click Adduct Designed for DNA Fluorescence Mismatch Sensing (pages 9590–9600)

      Dr. Xin Ming and Prof. Dr. Frank Seela

      Version of Record online: 5 JUL 2012 | DOI: 10.1002/chem.201103385

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      Nucleobase analogues: Compound 1 (see scheme) was designed to act as a nucleobase-discriminating fluorescence sensor for duplex DNA. Excellent mismatch discrimination was observed when nucleoside 1 was positioned opposite the four canonical nucleosides within the DNA duplex.

    8. Natural Products

      InCl3-Mediated Addition of Indole to Isatogens: An Expeditious Synthesis of 13-deoxy-Isatisine A (pages 9601–9611)

      Chepuri V. Suneel Kumar, Dr. Vedavati G Puranik and Dr. Chepuri V. Ramana

      Version of Record online: 4 JUL 2012 | DOI: 10.1002/chem.201103604

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      [Metal]-mediated: Methods for the addition of indoles to isatogens have been developed to prepare 2,2-disubstituted indolin-3-ones. The total synthesis of 13-deoxy-isatisine has been executed (see scheme) by featuring several [metal]-mediated reactions at the final stages, such as Sonogashira coupling, [Pd]-mediated nitro-alkyne cycloisomerization, and [In]-mediated addition of indole to an isatogen.

    9. Reaction Mechanisms

      Hydrolysis of Phosphotriesters: A Theoretical Analysis of the Enzymatic and Solution Mechanisms (pages 9612–9621)

      Dr. Violeta López-Canut, Dr. J. Javier Ruiz-Pernía, Dr. Raquel Castillo, Prof. Vicent Moliner and Prof. Iñaki Tuñón

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201103615

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      Hydrolysis of paraoxon, one of the most popular organophosphorus pesticides, in the active site of Pseudomonas diminuta phosphotriesterase (PTE) is shown by means of QM/MM simulations to takes place through an ANDN or associative mechanism both in solution and in the active site of PTE (see picture).

    10. Ligand Design

      [NiCl2(dppp)]-Catalyzed Cross-Coupling of Aryl Halides with Dialkyl Phosphite, Diphenylphosphine Oxide, and Diphenylphosphine (pages 9622–9627)

      Dr. Yu-Long Zhao, Guo-Jie Wu, You Li, Prof. Dr. Lian-Xun Gao and Prof. Dr. Fu-She Han

      Version of Record online: 2 JUL 2012 | DOI: 10.1002/chem.201103723

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      Making bonds: C[BOND]P bonds were formed by the Ni-catalyzed cross-coupling of aryl halides and phosphorus substrates without the need of external reductants. Aryl bromides and less reactive aryl chlorides underwent smooth coupling with several different phosphorus substrates to afford phosphonates, phosphine oxides, and phosphines (see scheme; dppp=1,3-bis(diphenylphosphino)propane). Due to the mild reaction conditions, a range of labile groups, such as ether, ester, ketone, and cyano groups, are tolerated.

    11. Photoactivation

      Photocaging Strategy for Functionalisation of Oligonucleotides and Its Applications for Oligonucleotide Labelling and Cyclisation (pages 9628–9637)

      Meng Su, Jie Wang and Prof. Dr. XinJing Tang

      Version of Record online: 5 JUL 2012 | DOI: 10.1002/chem.201103833

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      Caging oligonucleotides: Five photolabile phosphoramidites and four photolabile CPGs were synthesised for oligodeoxy-nucleotide modifications with phosphate, amine, acid, thiol and carbonyl moieties at 5′ and/or 3′ ends (see scheme). This study provides an alternative way to introduce functional groups into oligonucleotides and expand the scope of oligonucleotide bio-orthogonal labelling.

    12. Photochromism

      Syntheses and Fully Diastereospecific Photochromic Reactions of Thiophenophan-1-enes with Chiral Bridges (pages 9638–9644)

      Hirotsugu Jin-nouchi and Prof. Michinori Takeshita

      Version of Record online: 27 JUN 2012 | DOI: 10.1002/chem.201103970

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      Photo finish: Photochromic reactions of thiophenophan-1-enes with chiral polyether bridges occurred completely in a diastereospecific manner, even at high temperatures. Circular dichroism spectra and optical rotations changed photoreversibly according to the photochromic reactions between the enantiomers of the photoisomers (see figure).

    13. Regioselective Synthesis

      Multicomponent Reaction to Construct Spirocyclic Oxindoles with a Michael (Triple Michael)/Cyclization Cascade Sequence as the Key Step (pages 9645–9650)

      Dr. Jian Li, Ning Wang, Dr. Chunju Li and Prof. Dr. Xueshun Jia

      Version of Record online: 2 JUL 2012 | DOI: 10.1002/chem.201104071

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      Multiply your chemistry! Multicomponent reactions with readily available isocyanides, allenoates, and isatylidene malononitriles are disclosed. This protocol provides a synthetic route to an exocyclic double bond containing a spirocyclic ring in an efficient manner with excellent regioselectivity (see scheme).

    14. Natural Products

      Total Synthesis of Branimycin: An Evolutionary Approach (pages 9651–9668)

      Dr. Valentin S. Enev, Dr. Wolfgang Felzmann, Dr. Alexey Gromov, Dr. Stefan Marchart and Prof. Johann Mulzer

      Version of Record online: 4 JUL 2012 | DOI: 10.1002/chem.201200257

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      Competitive approach: The first total synthesis of the macrolactone antibiotic branimycin is described (see figure). The dehydrodecalin core was targeted via five competing approaches featuring various kinds of chiral elements and ring-closing methodology. In this “Darwinian” struggle the most successful route emerged and led to the completion of the synthesis.

    15. Imaging Agents

      Synthesis and Characterization of a Hypoxia-Sensitive MRI Probe (pages 9669–9676)

      Dr. Federico A. Rojas-Quijano, Dr. Gyula Tircsó, Enikő Tircsóné Benyó, Dr. Zsolt Baranyai, Huan Tran Hoang, Dr. Ferenc K. Kálmán, Dr. Praveen K. Gulaka, Prof. Vikram D. Kodibagkar, Prof. Silvio Aime, Prof. Zoltán Kovács and Prof. A. Dean Sherry

      Version of Record online: 27 JUN 2012 | DOI: 10.1002/chem.201200266

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      Hunting hypoxic cells: The DO3A-monoamide ligand with a 2-nitroimidazole moiety was synthesized with an aim to complex the GdIII ion as well as to target and visualize hypoxic cells by using the MRI technique (see figure). In vitro MRI experiments revealed that the conjugate might be suitable for assessment of hypoxia in vivo as the agent was selectively trapped in hypoxic (9L rat glioma) cells.

    16. Boron Chemistry

      Analysis of Why Boron Avoids sp2 Hybridization and Classical Structures in the BnHn+2 Series (pages 9677–9681)

      Edison Osorio, Dr. Jared K. Olson, Prof. William Tiznado and Prof. Alexander I. Boldyrev

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201200506

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      Classical structures composed of 2c–2e B[BOND]H and B[BOND]B bonds become progressively less stable along the series BnHn+2 (n=2–5). Relative energies increase from 2.9 kcal mol−1 in B2H4 to 62.3 kcal mol−1 in B5H7. It is believed that this occurs because boron atoms in the studied molecules tend to avoid sp2 hybridization and trigonal structures at the boron atoms, as in that case one 2p-AO is empty, and thus highly unfavorable (see figure).

    17. Total Synthesis

      Total Syntheses of (+)-Polygalolide A and (+)-Polygalolide B: Elucidation of the Absolute Stereochemistry and Biogenetic Implications (pages 9682–9690)

      Dr. Yukihito Sugano, Dr. Fumiaki Kikuchi, Akinori Toita, Prof. Dr. Seiichi Nakamura and Prof. Dr. Shunichi Hashimoto

      Version of Record online: 3 JUL 2012 | DOI: 10.1002/chem.201200542

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      Full control: Stereochemical insights into the biogenesis of polygalolides A and B have been provided by the stereocontrolled total synthesis of these natural products (see scheme), wherein the key steps include a highly diastereoselective hetero-Michael reaction, a [Rh2(OAc)4]-catalyzed carbonyl ylide formation/1,3-dipolar cycloaddition, and a Mukaiyama aldol-type reaction.

    18. Clusterfullerenes

      Synthesis, Isolation, and Spectroscopic Characterization of Holmium-Based Mixed-Metal Nitride Clusterfullerenes: HoxSc3−xN@C80 (x=1, 2) (pages 9691–9698)

      Yang Zhang, Dr. Alexey A. Popov, Sandra Schiemenz and Prof. Dr. Lothar Dunsch

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201200574

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      Ho-induced 13C and 45Sc NMR shifts: HoxSc3−xN@C80 (x=1, 2) nitride clusterfullerenes with Ih(7) and D5h(6) structures were synthesized and isolated, and their characterization by 13C and 45Sc variable-temperature NMR spectroscopy was accomplished for the first time for any Ho-based endohedral fullerene (see figure). Analysis of the Ho-induced paramagnetic shifts revealed the influence of the paramagnetic lanthanide ion on its surroundings.

    19. C[BOND]H Activation

      Direct Oxidative Coupling of Arenes with Olefins by Rh-Catalyzed C[BOND]H Activation in Air: Observation of a Strong Cooperation of the Acid (pages 9699–9704)

      Lu Zheng and Prof. Dr. Jianhui Wang

      Version of Record online: 4 JUL 2012 | DOI: 10.1002/chem.201200657

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      Give it some air: A [{RhCl(cod)}2]/CCl3COOH system for the oxidative coupling of arenes and olefins afforded their corresponding products with special chemo- and regioselectivity in high yields. This reaction provides an atom-efficient route to vinylarenes.

    20. Self-Assembly

      Glycosylated Star-Shaped Conjugated Oligomers for Targeted Two-Photon Fluorescence Imaging (pages 9705–9713)

      Guan Wang, Dr. Xinhai Zhang, Junlong Geng, Dr. Kai Li, Dr. Dan Ding, Dr. Kan-Yi Pu, Dr. Liping Cai, Prof. Yee-Hing Lai and Prof. Bin Liu

      Version of Record online: 28 JUN 2012 | DOI: 10.1002/chem.201200849

      Thumbnail image of graphical abstract

      Biological imaging: A star-shaped two-photon absorbing material (see scheme) with folic acid functionalization has been synthesized for targeted two-photon fluorescence imaging of MCF-7 cancer cells.

    21. Molecular Dynamics

      FMO-MD Simulations on the Hydration of Formaldehyde in Water Solution with Constraint Dynamics (pages 9714–9721)

      Dr. Makoto Sato, Prof. Dr. Hiroshi Yamataka, Dr. Yuto Komeiji and Prof. Dr. Yuji Mochizuki

      Version of Record online: 2 JUL 2012 | DOI: 10.1002/chem.201200874

      Thumbnail image of graphical abstract

      Formaldehyde in concert: The full-quantum mechanical molecular dynamics simulation on the hydration of formaldehyde in water solution (see figure) reveals that the hydration proceeds through a concerted mechanism, in which the nucleophilic addition and the proton transfer mediated by some water molecules occur simultaneously.

    22. Macrocycles

      Cyclic and Linear Polyferrocenes with Silicon and Tin as Alternating Bridges (pages 9722–9733)

      Bidraha Bagh, Nora C. Breit, Subhayan Dey, Dr. Joe B. Gilroy, Dr. Gabriele Schatte, Dr. Klaus Harms and Prof. Dr. Jens Müller

      Version of Record online: 2 JUL 2012 | DOI: 10.1002/chem.201200953

      Thumbnail image of graphical abstract

      Taking turns: Ferrocenophanes with alternating silicon and tin atoms at the bridging positions were prepared by using salt-metathesis reactions. Cyclic compounds with two- and four ferrocene moieties were isolated that showed fluxional behavior in solution. Larger macrocycles of up to 20 ferrocene moieties were also formed in the reaction mixtures and could be detected by mass spectrometry (MALDI-TOF).

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      Preview: Chem. Eur. J. 32/2012 (page 9735)

      Version of Record online: 20 JUL 2012 | DOI: 10.1002/chem.201290134

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