Angewandte Chemie International Edition
Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Upcoming Hot Papers
Hot Papers are chosen by the Editors for their importance in a rapidly evolving field of high current interest. Many of the "Very Important Papers" (VIPs) would certainly qualify to be included here, but such a duplication is avoided.
Renewable Carbon Sources
Cyclic Alkyl Amino Carbene (CAAC) Ruthenium Complexes as Remarkably Active Catalysts for Ethenolysis
Dr. Vanessa M. Marx, Alexandra H. Sullivan, Dr. Mohand Melaimi, Dr. Scott C. Virgil, Dr. Benjamin K. Keitz, Dr. David S. Weinberger, Prof. Guy Bertrand and Prof. Robert H. Grubbs
A new series of olefin-metathesis catalysts containing cyclic alkyl amino carbene (CAAC) ligands exhibit unprecedented activity in the ethenolysis of methyl oleate. This work advances the state-of-the-art of the ethenolysis reaction and is expected to find particular use in large-scale industrial applications.
Unusual Ultra-Hydrophilic, Porous Carbon Cuboids for Atmospheric-Water Capture
Dr. Guang-Ping Hao, Giovanni Mondin, Dr. Zhikun Zheng, Tim Biemelt, Stefan Klosz, René Schubel, Prof. Alexander Eychmüller and Prof. Stefan Kaskel
Thirsty materials: A new class of ultra-hydrophilic porous carbon cuboids shows the best performance for atmospheric-water capture among porous carbons to date. It may serve as a model material for research on carbon chemistry, a new material for water capture, and find use in applications requiring highly hydrophilic surfaces, porosity, and stability.
Phosphorus-Doped Graphitic Carbon Nitrides Grown in Situ on Carbon-Fiber Paper: Flexible and Reversible Oxygen Electrodes
Dr. Tian Yi Ma, Jingrun Ran, Prof. Sheng Dai, Prof. Mietek Jaroniec and Prof. Shi Zhang Qiao
Electrodes, on a roll: Flexible and reversible oxygen electrodes composed of nanostructured P-doped graphitic carbon nitrides grown on carbon-fiber paper exhibit outstanding catalytic activity and stability towards both oxygen reduction (ORR) and oxygen evolution reactions (OER) in different folded and rolled-up forms. They can be used as efficient air cathodes in Zn–air batteries.
Hydrodeoxygenation of Vicinal OH Groups over Heterogeneous Rhenium Catalyst Promoted by Palladium and Ceria Support
Nobuhiko Ota, Dr. Masazumi Tamura, Dr. Yoshinao Nakagawa, Prof. Kazu Okumura and Prof. Keiichi Tomishige
Ultra-fast double cutting: High yields (>99 %), turnover frequencies (TOF, 300 h−1), and turnover numbers (TON, 10 000) are achieved in the simultaneous hydrodeoxygenation of 1,4-anhydroerythritol to tetrahydrofuran over heterogeneous ReOx–Pd/CeO2 catalyst. This catalyst can be applied to sugar alcohols; mono-alcohols and diols are obtained in high yields (≥85 %).
Synthesis of Inorganic Structural Isomers By Diffusion-Constrained Self-Assembly of Designed Precursors: A Novel Type of Isomerism
Marco Esters, Matti B. Alemayehu, Zachary Jones, Dr. N. T. Nguyen, Dr. Michael D. Anderson, Corinna Grosse, Prof. Saskia F. Fischer and Prof. David C. Johnson
Just as organic molecules have isomers resulting from different interconnectivity (as shown for C4H8), layered compounds have similar structural isomers. The six possible structural isomers containing four Se-Nb-Se trilayers and four bilayers of PbSe were synthesized from designed precursors. Thus, thousands of new compounds may be selectively prepared from fragments of known compounds.
Screening for Protein Phosphorylation Using Nanoscale Reactions on Microdroplet Arrays
Simon K. Küster, Dr. Martin Pabst, Prof. Renato Zenobi and Prof. Petra S. Dittrich
Phosphopeptide screening: A mass spectrometry-based screening method detects protein phosphorylation in complex protein mixtures without extensive MS/MS experiments. The method employs droplet microfluidics to integrate nanoliter phosphatase reactions in a nano-LC-MALDI-MS workflow. The selective dephosphorylation of every second LC fraction induces characteristic peak fluctuations that can be used to identify even low-abundant phosphopeptides.
High-Resolution Single-Molecule Fluorescence Imaging of Zeolite Aggregates within Real-Life Fluid Catalytic Cracking Particles
Zoran Ristanović, Dr. Marleen M. Kerssens, Alexey V. Kubarev, Frank C. Hendriks, Dr. Peter Dedecker, Prof. Dr. Johan Hofkens, Prof. Dr. Maarten B. J. Roeffaers and Prof. Dr. Bert M. Weckhuysen
Real-life fluid catalytic cracking (FCC) catalyst particles have been studied with a combination of single-molecule fluorescence nanoscopy and stochastic optical fluctuation imaging methods. Zeolite ZSM-5 aggregates and their reactivity could be mapped with unprecedented spatiotemporal resolution and sensitivity, revealing significant differences in turnover frequencies of the embedded individual zeolite particulates.
Decarbonylative Radical Coupling of α-Aminoacyl Tellurides: Single-Step Preparation of γ-Amino and α,β-Diamino Acids and Rapid Synthesis of Gabapentin and Manzacidin A
Dr. Masanori Nagatomo, Hayato Nishiyama, Haruka Fujino and Prof. Dr. Masayuki Inoue
Upon activation by Et3B and O2 at ambient temperature, α-aminoacyl tellurides were readily converted into α-amino carbon radicals through facile decarbonylation, which then reacted intermolecularly with acrylates or glyoxylic oxime ethers to generate various γ-amino and α,β-diamino acids. This mild and powerful coupling method was also applied to the synthesis of gabapentin and the natural product (−)-manzacidin A.
A Hierarchical Tin/Carbon Composite as an Anode for Lithium-Ion Batteries with a Long Cycle Life
Dr. Xingkang Huang, Dr. Shumao Cui, Dr. Jingbo Chang, Peter B. Hallac, Christopher R. Fell, Yanting Luo, Bernhard Metz, Junwei Jiang, Patrick T. Hurley and Prof. Junhong Chen
High capacity anodes: A tin/carbon hierarchical structure was designed, in which some of the nanosized Sn particles are anchored on the tips of carbon nanotubes that are rooted on the surfaces of microsized hollow carbon cubes while other Sn nanoparticles are encapsulated in the hollow carbon cubes. Such a unique structure allows the Sn particles to accommodate the volume change upon lithiation.
Sequential Synthesis of Coordination Polymersomes
Dr. Ryo Ohtani, Dr. Munehiro Inukai, Dr. Yuh Hijikata, Dr. Tetsuya Ogawa, Dr. Mikihito Takenaka, Prof. Masaaki Ohba and Prof. Susumu Kitagawa
The sequential synthesis of coordination polymers on lipid bilayers provides novel organic–inorganic hybrid liposomes, so-called coordination polymersomes (CPsomes), which formed unilamellar faceted spheres with plain coordination polymer raft domains that consist of cyanide-bridged linkages based on a lipophilic building unit. This is a novel approach for the construction of artificial raft domains and for creating composite soft materials.
Photochromic Metal–Organic Frameworks: Reversible Control of Singlet Oxygen Generation
Jihye Park, Dawei Feng, Shuai Yuan and Prof. Dr. Hong-Cai Zhou
Back and forth: Through a classical pillar-layer structure constructed with mixed linkers, two photochromic metal–organic frameworks, PC-PCN and SO-PCN, have been developed. SO-PCN integrates a photochromic switch and photosensitizer, and has demonstrated reversible control of 1O2 generation (see figure).
Natural Product Synthesis
Total Synthesis of (±)-Hippolachnin A
Stefan A. Ruider, Tobias Sandmeier and Prof. Dr. Erick M. Carreira
Brevity makes sweetness! The first total synthesis of the marine polyketide (±)-hippolachnin A is realized in nine steps and an overall yield of 9 %. The synthesis relies on the strategic application of an ene cyclization, which provides rapid access to the oxacyclobutapentalene core skeleton.
Long-Lived Engineering of Glycans to Direct Stem Cell Fate
Abigail Pulsipher, Matthew E. Griffin, Shannon E. Stone and Prof. Linda C. Hsieh-Wilson
Sweet display: A method for the long-lived presentation of specific glycans on cell surfaces is reported. HaloTag proteins (HTP) were utilized to covalently attach defined heparan sulfate (HS) structures to embryonic stem cell membranes. Highly sulfated HS induced accelerated exit from self-renewal and differentiation into neuronal cell types, demonstrating the potential of glycan engineering to drive important physiological processes.
Hydrogen Storage Materials: Room-Temperature Wet-Chemistry Approach toward Mixed-Metal Borohydrides
Dr. Tomasz Jaroń, Piotr A. Orłowski, Wojciech Wegner, Dr. Karol J. Fijałkowski, Dr. Piotr J. Leszczyński and Prof. Wojciech Grochala
Avoiding “dead mass”: Hydrogen-rich mixed-metal borohydrides, which are promising materials for the chemical storage of hydrogen, were prepared by a wet-chemistry approach. This method is based on a metathesis reaction, does not lead to a high percentage of “dead mass” (metal halides and coordinated solvents), and was exemplified for a series of MZn(BH4) borohydrides (M=Li, Na, K).
A Three-Minute Synthesis and Purification of Ibuprofen: Pushing the Limits of Continuous-Flow Processing
Dr. David R. Snead and Prof. Dr. Timothy F. Jamison
Within three minutes, ibuprofen was assembled from its elementary building blocks with an average yield of above 90 % for each step. The process featured a Friedel–Crafts acylation run under neat conditions and promoted by AlCl3, an exothermic in-line quench of flocculation-prone concentrated AlCl3, liquid–liquid separations run at or above 200 psi to give solvent-free product, and the continuous pumping of a neat aggressive oxidant.
The Isothiocyanato Moiety: An Ideal Protecting Group for the Stereoselective Synthesis of Sialic Acid Glycosides and Subsequent Diversification
Appi Reddy Mandhapati, Dr. Salla Rajender, Jonathan Shaw and Prof. Dr. David Crich
Very high α-selectivity is found in the coupling reactions of a readily prepared crystalline isothiocyanate-protected sialyl donor with typical carbohydrate alcohols (Ada=1-adamantanyl). The isothiocyanate group is subsequently transformed into a number of functional groups including CH and CC bonds, amides, and thioureas, all in one step. A guanidino function is also accessible.
Covalent Reversible Cross-Linking
“Post-It” Type Connected DNA Created with a Reversible Covalent Cross-Link
Dr. María Tomás-Gamasa, M. Sc. Sascha Serdjukow, M. Sc. Meng Su, Dr. Markus Müller and Prof. Dr. Thomas Carell
Reversible bond formation was used as a design principle to create a “post-it”-type cross-linking unit. The aldehyde–amine DNA cross-link endows DNA duplexes with a reversible but unusual high stability.
Natural Product Synthesis
Total Synthesis of the Protected Aglycon of Fidaxomicin (Tiacumicin B, Lipiarmycin A3)
Dr. Hideki Miyatake-Ondozabal, Elias Kaufmann and Prof. Dr. Karl Gademann
Fidaxomicin fix: The core aglycon of the clinically used antibiotic fidaxomicin was synthesized by using ring-closing metathesis for macrocyclization. This synthetic route is highly convergent and the key steps include a diastereoselective vinylogous Mukaiyama aldol reaction of a novel substrate, Yamaguchi esterification, and a Stille coupling reaction between two sterically hindered intermediates.
G-Quartet-Based Nanostructure for Mimicking Light-Harvesting Antenna
Fang Pu, Li Wu, Xiang Ran, Prof. Jinsong Ren and Prof. Xiaogang Qu
Curl up and dye: G-quartet-based hierarchical nanofibers generated from the self-assembly of guanosine 5′-monophosphate with Sr2+ ions have been developed to mimic natural light-harvesting antenna. Three dyes (yellow, orange, red spheres in picture) were confined simultaneously in the nanofibers and brought into proximity, thus allowing for a two-step FRET process. Photocurrent is generated upon irradiation with visible light.
Nickel-Catalyzed Dehydrogenative Cross-Coupling: Direct Transformation of Aldehydes into Esters and Amides
Dr. Aaron M. Whittaker and Prof.Dr. Vy M. Dong
Nickel for a change: By exploring a new mode of nickel-catalyzed cross-coupling, both aromatic and aliphatic aldehydes can be directly transformed into either esters or amides. The success of this oxidative coupling depends on the appropriate choice of catalyst and organic oxidant (α,α,α-trifluoroacetophenone or benzaldehyde). Mechanistic data supports a catalytic cycle involving oxidative addition into the aldehyde CH bond.
Metal Dendrimers: Synthesis of Hierarchically Stellated Nanocrystals by Sequential Seed-Directed Overgrowth
Rebecca G. Weiner and Prof. Sara E. Skrabalak
Building connections: Sequential seed-directed overgrowth provides a route to metal dendrimers, which are hierarchically branched nanocrystals analogous to molecular dendrimers. By manipulating the seed shape, the number of branches is readily controlled. By repeating the seed-mediated co-reduction process, iterative chain growth with concentric branching is possible.
Design and Synthesis of High-Affinity Dimeric Inhibitors Targeting the Interactions between Gephyrin and Inhibitory Neurotransmitter Receptors
Dr. Hans Michael Maric, Vikram Babu Kasaragod, Dr. Linda Haugaard-Kedström, Dr. Torben Johann Hausrat, Prof. Dr. Matthias Kneussel, Prof. Dr. Hermann Schindelin and Prof. Dr. Kristian Strømgaard
Double-teaming: Dimeric peptide ligands were developed that target gephyrin, the central scaffolding protein for inhibitory neurotransmitter receptors in the brain, with unprecedented high affinity. Dimerization also substantially improved the serum stability, thus providing compounds with great promise for further studies of gephyrin–receptor interactions. The X-ray structure shows one of these peptides in complex with two monomers of the gephyrin E domain.
Asymmetric Dearomatization of β-Naphthols through an Amination Reaction Catalyzed by a Chiral Phosphoric Acid
Shou-Guo Wang, Dr. Qin Yin, Dr. Chun-Xiang Zhuo and Prof. Dr. Shu-Li You
Useful skeletons: An electrophilic amination reaction catalyzed by chiral phosphoric acid is the basis for a highly efficient asymmetric dearomatization of naphthols. This protocol provides functionalized β-naphthalenone compounds with a chiral quaternary carbon center in excellent yields and enantioselectivity. These motifs are found in various biologically active natural products and therapeutic reagents.
Metal-Free Carbonylations by Photoredox Catalysis
Ing. Michal Majek and Prof. Dr. Axel Jacobi von Wangelin
A metal-free and base-free carbonylation has been developed which affords primary, secondary, and tertiary alkyl benzoates under irradiation with visible light in the presence of eosin Y as a photocatalyst. The mechanism has been studied by spectroscopic, theoretical, and preparative methods, and appears to involve intermediate aryl and aroyl radical species as well as a light-driven one-electron redox cycle without any sacrificial redox partner.
Ionic Liquids: Not only Structurally but also Dynamically Heterogeneous
Zhuan-Ping Zheng, Prof. Wen-Hui Fan, Soham Roy, Dr. Kamila Mazur, Andreas Nazet, Prof. Richard Buchner, Prof. Mischa Bonn and Dr. Johannes Hunger
Size doesn′t matter: The equilibration of the ionic ammonium group in protic ionic liquids after an ultrafast temperature jump depends on the anion but not on the size of the hydrophobic side chain. This equilibration of the ionic domains is approximately two times slower than restructuring within the hydrophobic alkyl domains, which demonstrates the dynamic heterogeneity in ionic liquids.
Cobalt-Catalyzed CH Cyanation of Arenes and Heteroarenes
M. Sc. Jie Li and Prof. Dr. Lutz Ackermann
As directed: The title reactions were accomplished with in situ generated cobalt(III) carboxylate complexes for highly efficient CH activations. The direct cyanation proved viable with removable directing groups and displayed a broad substrate scope and mild reaction conditions.
Porous Liquids: A Promising Class of Media for Gas Separation
Dr. Jinshui Zhang, Dr. Song-Hai Chai, Dr. Zhen-An Qiao, Dr. Shannon M. Mahurin, Dr. Jihua Chen, Dr. Youxing Fang, Dr. Shun Wan, Kimberly Nelson, Dr. Pengfei Zhang and Prof. Sheng Dai
Perforated liquids: Functionalizing hollow silica spheres with suitable polymer species can produce a porous liquid containing empty silica cavities. Taking advantage of their liquid-like polymeric matrixes as the separation medium and the empty cavities as the gas transport pathway they can function as a promising candidates for gas separation.
A Twist-Bend Nematic Phase Driven by Hydrogen Bonding
Suzanne M. Jansze, Dr. Alfonso Martínez-Felipe, Prof. John M. D. Storey, Dr. Antonius T. M. Marcelis and Prof. Corrie T. Imrie
Intriguing interplay: When the benzoic acid units in 4-[6-(4′-cyanobiphenyl-4-yl)hexyloxy]benzoic acid dimerize by hydrogen bonding (see picture), promesogenic liquid crystal trimers form. These supramolecular complexes show an enantiotropic nematic phase, which on cooling transforms into the twist-bend nematic phase in which the bent, achiral complexes spontaneously form helical structures.
Atomic-Resolution Three-Dimensional Structure of Amyloid β Fibrils Bearing the Osaka Mutation
Dr. Anne K. Schütz, Dr. Toni Vagt, Dr. Matthias Huber, Dr. Oxana Y. Ovchinnikova, Riccardo Cadalbert, Dr. Joseph Wall, Prof. Dr. Peter Güntert, Dr. Anja Böckmann, Prof. Dr. Rudi Glockshuber and Prof. Dr. Beat H. Meier
A fold not observed before: The atomic-resolution fibril structure of the Aβ1-40 peptide with the Osaka mutation (E22Δ), which is associated with early-onset Alzheimer's disease, differs substantially from all previously proposed models. In this complex structure the deletion mutation is found in a β turn.
Benzoxazolone Carboxamides: Potent and Systemically Active Inhibitors of Intracellular Acid Ceramidase
Dr. Daniela Pizzirani, Dr. Anders Bach, Dr. Natalia Realini, Dr. Andrea Armirotti, Dr. Luisa Mengatto, Dr. Inga Bauer, Dr. Stefania Girotto, Dr. Chiara Pagliuca, Dr. Marco De Vivo, Dr. Maria Summa, Dr. Alison Ribeiro and Prof. Daniele Piomelli
A key regulator of the sphingolipid metabolism is acid ceramidase (AC), which offers a molecular target in disorders such as cancer and inflammation, in which sphingolipid signaling might be dysfunctional. The shown compound is metabolically stable, inhibits AC activity both in vitro and in vivo, and can thus be used as a potent chemical probe to investigate the roles of ceramides in physiology and pathology.
Construction of Matryoshka-Type Structures from Supercharged Protein Nanocages
Dr. Tobias Beck, Stephan Tetter, Matthias Künzle and Prof. Dr. Donald Hilvert
Cages within cages: By exploiting electrostatic interactions between two supercharged protein containers, namely supercharged lumazine synthase (red) and supercharged ferritin (blue) loaded with iron-oxide nanoparticles (black), nested Matryoshka-type structures were assembled. These cage-within-cage structures consist of two layers of protein surrounding iron oxide nanoparticles in a manner reminiscent of Russian dolls.
Boron Redox Chemistry
Boron as a Powerful Reductant: Synthesis of a Stable Boron-Centered Radical-Anion Radical-Cation Pair
Dr. Philipp Bissinger, Prof. Dr. Holger Braunschweig, Dr. Alexander Damme, Dr. Christian Hörl, Dr. Ivo Krummenacher and Dr. Thomas Kupfer
The tailor-made diborene IiPr⋅(iPr)BB(iPr)⋅IiPr features an extremely electron-rich B–B double bond making it one of the most powerful neutral organic reductants known to date (E1/2=−1.95 V). Its reducing power was successfully exploited in the synthesis of a very rare boron-centered radical-anion radical-cation pair by one-electron reduction of a borole, MesBC4Ph4. IiPr=1,3-diisopropylimidazol-2-ylidene.
Green-Solvent-Processed Molecular Solar Cells
Xiaofen Chen, Dr. Xiaofeng Liu, Mark A. Burgers, Dr. Ye Huang and Prof. Dr. Guillermo C. Bazan
Molecular solar cells with high efficiencies can be fabricated from the green solvent 2-MeTHF. The light-harvesting semiconducting layer comprises a molecular donor with intermediate dimensions and a soluble fullerene derivative. No specific structural modifications are required on the semiconductors in order to use sustainable resources. PCE=power conversion efficiency.
Graphitic Carbon Nitride Nanoribbons: Graphene-Assisted Formation and Synergic Function for Highly Efficient Hydrogen Evolution
Yang Zhao, Fei Zhao, Xiaopeng Wang, Chenyu Xu, Zhipan Zhang, Prof. Gaoquan Shi and Prof. Liangti Qu
A non-metallic electrocatalyst: A three-dimensional architecture of in situ formed 1D graphitic carbon nitride nanoribbons on two-dimensional graphene sheets has been prepared (see picture). The compound is a highly efficient electrocatalyst for the hydrogen evolution and shows a low overpotential and an extremely large exchange current density, which is even larger than that of metal catalysts.