Angewandte Chemie International Edition

Cover image for Vol. 54 Issue 28

Editor: Peter Gölitz, Deputy Editors: Neville Compton, Haymo Ross

Online ISSN: 1521-3773

Associated Title(s): Angewandte Chemie, Chemistry - A European Journal, Chemistry – An Asian Journal, ChemistryOpen, ChemPlusChem, Zeitschrift für Chemie

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.

Lithium-Ion Batteries

A New Perspective on Li–SO2 Batteries for Rechargeable Systems

Hee-Dae Lim, Hyeokjun Park, Hyungsub Kim, Jinsoo Kim, Byungju Lee, Youngjoon Bae, Hyeokjo Gwon and Prof. Kisuk Kang

A New Perspective on Li–SO2 Batteries for Rechargeable SystemsEnergy storage: Although Li–SO2 batteries have been used as primary batteries to date, the feasibility of a rechargeable Li–SO2 battery is demonstrated based on the reversible formation and decomposition of the solid product Li2S2O4 (see picture). The observed energy efficiency of the Li–SO2 system is significantly better than that of the Li–O2 system.

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Functional Nanostructures

A Universal Approach to Ultrasmall Magneto-Fluorescent Nanohybrids

Artur Feld, Jan-Philip Merkl, Dr. Hauke Kloust, Dr. Sandra Flessau, Dr. Christian Schmidtke, Christopher Wolter, Dr. Johannes Ostermann, Michael Kampferbeck, Robin Eggers, Prof. Dr. Alf Mews, Dr. Theo Schotten and Prof. Dr. Horst Weller

A Universal Approach to Ultrasmall Magneto-Fluorescent NanohybridsMatching unlikely pairs: In a two-step procedure, iron oxide nanocrystals were initially encapsulated in a polystyrene (PS) shell and subsequently used as beads for a controlled assembly of elongated quantum dots/quantum rods (QDQRs) The fluorescence of the QDQRs and magnetism of iron oxide were perfectly preserved in the resulting nanohybrids.

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DNA Structures

Post-Assembly Stabilization of Rationally Designed DNA Crystals

Jiemin Zhao, Arun Richard Chandrasekaran, Qian Li, Xiang Li, Ruojie Sha, Prof. Nadrian C. Seeman and Prof. Chengde Mao

Post-Assembly Stabilization of Rationally Designed DNA CrystalsAdded stability: Owing to weak inter-unit cohesion, self-assembled DNA crystals tend to be fragile. Such nanostructures can be effectively stabilized by the addition of a molecule that binds to the cohesive sites and stabilizes the inter-unit interactions. Whereas the original DNA crystals are only stable in solutions of high ionic strength (e.g., ≥1.2 M (NH4)2SO4), the stabilized crystals are stable at much lower ionic strengths.

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Heteroacenes

Fused Thiophene-Pyrrole-Containing Ring Systems up to a Heterodecacene

Christoph Wetzel, Eduard Brier, Astrid Vogt, Dr. Amaresh Mishra, Dr. Elena Mena-Osteritz and Prof. Dr. Peter Bäuerle

Fused Thiophene-Pyrrole-Containing Ring Systems up to a HeterodecaceneA bunch of fives: A new family of fused thiophene-pyrrole-containing S,N-heteroacenes with extended π-conjugation was synthesized (S yellow, N blue, C gray, H white). The characterization of optical and redox properties showed valuable structure–property relationships.

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Synthetic Methods

Enantioselective α-Alkylation of Aldehydes by Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from β-Cyanoaldehydes

Eric R. Welin, Dr. Alexander A. Warkentin, Dr. Jay C. Conrad and Prof. Dr. David W. C. MacMillan

Enantioselective α-Alkylation of Aldehydes by Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from β-CyanoaldehydesA combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective cyanoalkylation of aldehydes. This synergistic catalysis protocol makes possible the coupling of two highly versatile yet orthogonal functionalities.

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Metal–Metal Bonds

A Mixed-Valence Tri-Zinc Complex, [LZnZnZnL] (L=Bulky Amide), Bearing a Linear Chain of Two-Coordinate Zinc Atoms

Jamie Hicks, Emma J. Underhill, Dr. Christos E. Kefalidis, Prof. Laurent Maron and Prof. Cameron Jones

A Mixed-Valence Tri-Zinc Complex, [LZnZnZnL] (L=Bulky Amide), Bearing a Linear Chain of Two-Coordinate Zinc AtomsForm an orderly queue! Reduction of an extremely bulky amido (L*) zinc bromide complex, [L*ZnBr] with a magnesium(I) dimer yields the formally zinc(0) complex, [L*ZnMg(MesNacnac)], which contains the first example of an unsupported Zn[BOND]Mg bond. Its subsequent reaction with ZnBr2 affords the unprecedented mixed-valence, linear tri-zinc complex, [L*ZnIZn0ZnIL*] (see picture).

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Polypharmacology

Fragment-Based Discovery of a Dual pan-RET/VEGFR2 Kinase Inhibitor Optimized for Single-Agent Polypharmacology

Brendan Frett, Francesca Carlomagno, Maria Luisa Moccia, Annalisa Brescia, Giorgia Federico, Valentina De Falco, Brittany Admire, Zhongzhu Chen, Wenqing Qi, Massimo Santoro and Hong-yu Li

Fragment-Based Discovery of a Dual pan-RET/VEGFR2 Kinase Inhibitor Optimized for Single-Agent PolypharmacologyDual inhibition: A kinase-directed fragment-based screen identified a novel active pharmacophore for the RET tyrosine kinase (RET=rearranged during transfection). In a medicinal chemistry/polypharmacology approach, Pz-1 was found to be a dual pan-RET/VEGFR2 inhibitor and able to simultaneously treat the parenchyma (RET) and stroma (VEGFR2) of RET-driven tumors in cell and xenograft models.

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Pincer Complexes

Reversible α-Hydrogen and α-Alkyl Elimination in PC(sp3)P Pincer Complexes of Iridium

Dr. Klara J. Jonasson, Dr. Alexey V. Polukeev, Dr. Rocío Marcos, Prof. Mårten S. G. Ahlquist and Prof. Ola F. Wendt

Reversible α-Hydrogen and α-Alkyl Elimination in PC(sp3)P Pincer Complexes of IridiumAn iridium pincer complex undergoes reversible α-alkyl elimination. Under certain conditions, this fundamentally new process for C(sp3)[BOND]C(sp3) bond cleavage has a low barrier that is comparable with that of well known α-hydrogen elimination reactions. Kinetic studies, activation parameters, and DFT calculations are also discussed.

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Non-ribosomal Peptides

Structure Elucidation and Activity of Kolossin A, the D-/L-Pentadecapeptide Product of a Giant Nonribosomal Peptide Synthetase

Prof. Dr. Helge B. Bode, Dr. Alexander O. Brachmann, Dr. Kirtikumar B. Jadhav, Dr. Lydia Seyfarth, Dipl.-Chem. Christina Dauth, Dr. Sebastian W. Fuchs, Dr. Marcel Kaiser, Dr. Nick R. Waterfield, Dipl.-Phys. Holger Sack, Prof. Dr. Stefan H. Heinemann and Prof. Dr. Hans-Dieter Arndt

Structure Elucidation and Activity of Kolossin A, the <span class="smallCaps">D</span>-/<span class="smallCaps">L</span>-Pentadecapeptide Product of a Giant Nonribosomal Peptide SynthetaseSleeping giant: A 1.8 MDa nonribosomal peptide synthetase (NRPS) was identified in the entomopathogenic bacterium Photorhabdus luminescens and its production was activated. Its 15-mer D-/ L-peptide product kolossin A was structurally characterized by combining genomic analysis of the silent gene cluster, molecular biology, LC–MS, and total synthesis. A stereoisomer of kolossin A was found to be active against the pathogen that causes African sleeping sickness.

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Nitrogen Fixation

Metal-Mediated Production of Isocyanates, R3EN[DOUBLE BOND]C[DOUBLE BOND]O from Dinitrogen, Carbon Dioxide, and R3ECl

Andrew J. Keane, Wesley S. Farrell, Brendan L. Yonke, Peter Y. Zavalij and Prof. Lawrence R. Sita

Metal-Mediated Production of Isocyanates, R3EN<img src="http://onlinelibrarystatic.wiley.com/undisplayable_characters/00f8fe.gif" alt="[DOUBLE BOND]" />C<img src="http://onlinelibrarystatic.wiley.com/undisplayable_characters/00f8fe.gif" alt="[DOUBLE BOND]" />O from Dinitrogen, Carbon Dioxide, and R3EClTandem fixation: A highly efficient and versatile chemical cycle has been developed for the production of isocyanates through the molecular fixation of N2, CO2, and R3ECl (E=C, Si and Ge). Key steps include a simultaneous nitrene-group transfer and oxygen-atom transfer.

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Nanoparticle Morphology

Sequential Anion and Cation Exchange Reactions for Complete Material Transformations of Nanoparticles with Morphological Retention

James M. Hodges, Karel Kletetschka, Julie L. Fenton, Carlos G. Read and Prof. Raymond E. Schaak

Sequential Anion and Cation Exchange Reactions for Complete Material Transformations of Nanoparticles with Morphological RetentionComplete transformation: Metal oxide nanocrystals can be transformed into chalcogenides of different metals using sequential anion and cation exchange reactions. The products retain the morphology of the starting material, but contain entirely different elemental components. Morphology and composition control in colloidal nanocrystal synthesis are thus fully decoupled.

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Plasmonics

Black Gold: Plasmonic Colloidosomes with Broadband Absorption Self-Assembled from Monodispersed Gold Nanospheres by Using a Reverse Emulsion System

Dilong Liu, Dr. Fei Zhou, Cuncheng Li, Tao Zhang, Honghua Zhang, Prof. Weiping Cai and Prof. Yue Li

Black Gold: Plasmonic Colloidosomes with Broadband Absorption Self-Assembled from Monodispersed Gold Nanospheres by Using a Reverse Emulsion SystemBlack colloidosomes: 3D hollow plasmonic colloidosomes (see picture) composed of hexagonal close-packed gold nanospheres were self-assembled by a new reverse water-in-1-butanol emulsion system. These gold colloidosomes display a strong plasmonic coupling effect with broadband light absorption, show black color intrinsically, and are therefore denoted as black gold.

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Colloidal Crystals

Photonic Crystals with a Reversibly Inducible and Erasable Defect State Using External Stimuli

Mao Chen, Yapeng Zhang, Siyu Jia, Lin Zhou, Prof. Dr. Ying Guan and Prof. Dr. Yongjun Zhang

Photonic Crystals with a Reversibly Inducible and Erasable Defect State Using External StimuliArtificial defects: Doped microgel colloidal crystals were facilely assembled from two microgels with the same size. A defect state in the crystals could be reversibly induced and erased by external stimuli (see picture).

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Near-Infrared Luminescence

The Radiative Lifetime in Near-IR-Luminescent Ytterbium Cryptates: The Key to Extremely High Quantum Yields

M. Sc. Christine Doffek and Prof. Dr. Michael Seitz

The Radiative Lifetime in Near-IR-Luminescent Ytterbium Cryptates: The Key to Extremely High Quantum YieldsGenerating a warm glow indeed: By a combination of conventional optimization strategies with a new approach, near-IR-emissive ytterbium cryptates with unprecedented photoluminescence quantum yields of up to 12 % have been realized. The key to these successful luminophores is the judicious chemical design that makes the metal-centered emissive transition much more competitive with respect to quenching processes.

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Homogeneous Catalysis

An Aluminum Hydride That Functions like a Transition-Metal Catalyst

Prof. Zhi Yang, Dr. Mingdong Zhong, Dr. Xiaoli Ma, Dr. Susmita De, M. Sc. Chakkittakandiyil Anusha, Dr. Pattiyil Parameswaran and Prof. Herbert W. Roesky

An Aluminum Hydride That Functions like a Transition-Metal CatalystCanned catalysis: The aluminum hydride [LAlH(OTf)] has an excellent catalytic activity both in the hydroboration and the addition of trimethylsilyl cyanide (TMSCN) to aldehydes and ketones. The compound was synthesized by the reaction of [LAlH2] (L=HC(CMeNAr)2, Ar=2,6-iPr2C6H3) with MeOTf (Tf=SO2CF3). Theoretical calculations show that the catalyst initially acts as a hydride donor to the carbonyl group. HBPin=pinacolborane.

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CO Reduction

Reductive Cleavage of Carbon Monoxide by a Disilenide

Dr. Moumita Majumdar, Dipl.-Chem. Isabell Omlor, MSc Cem B. Yildiz, Prof. Dr. Akin Azizoglu, Dr. Volker Huch and Prof. Dr. David Scheschkewitz

Reductive Cleavage of Carbon Monoxide by a DisilenideHidden powers: Lithium disilenide reductively cleaves the strongest bond in chemistry, the C[TRIPLE BOND]O bond of carbon monoxide, at room temperature. A key step in the Fischer–Tropsch process is reiterated by an anionic molecular main-group system with Si[DOUBLE BOND]Si bonds. The mechanism is elucidated by DFT calculations and model reactions with Group 6 hexacarbonyls.

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Iridium Catalysis

The Retro-Hydroformylation Reaction

Dr. Shuhei Kusumoto, Toshiumi Tatsuki and Prof. Dr. Kyoko Nozaki

The Retro-Hydroformylation ReactionThe reverse reaction of hydroformylation, a so-called retro-hydroformylation, has been developed. In the presence of an iridium catalyst, alkenes were obtained from aliphatic aldehydes in up to 91 % yield along with the quantitative evolution of synthesis gas. Mechanistic studies suggest that this reaction indeed proceeds by a retro-hydroformylation mechanism.

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Antiproliferation

Small-Molecule-Mediated Degradation of the Androgen Receptor Through Hydrophobic Tagging

Dr. Jeffrey L. Gustafson, Dr. Taavi K. Neklesa, Carly S. Cox, Dr. Anke G. Roth, Dr. Dennis L. Buckley, Dr. Hyun Seop Tae, Dr. Thomas B. Sundberg, D. Blake Stagg, Dr. John Hines, Prof. Donald P. McDonnell, Dr. John D. Norris and Prof. Craig M. Crews

Small-Molecule-Mediated Degradation of the Androgen Receptor Through Hydrophobic TaggingMaking the problem go away: Most prostate tumor growth is driven by the action of the androgen receptor (AR). Resistance to current chemotherapies for prostate cancer can occur when the androgen receptor is either overexpressed or mutated. Coupling of an AR agonist to an adamantyl “hydrophobic tag” resulted in a molecule that induces AR degradation, even in drug-resistant prostate tumor cells.

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Nanobioanalysis

Real-time Monitoring of Discrete Synaptic Release Events and Excitatory Potentials within Self-reconstructed Neuro-muscular Junctions

Yu-Tao Li, Shu-Hui Zhang, Xue-Ying Wang, Xin-Wei Zhang, Dr. Alexander I. Oleinick, Prof. Dr. Irina Svir, Prof. Dr. Christian Amatore and Prof. Dr. Wei-Hua Huang

Real-time Monitoring of Discrete Synaptic Release Events and Excitatory Potentials within Self-reconstructed Neuro-muscular JunctionsA microfluidic chip was developed taking advantage of a carbon fiber nanoelectrodes (CFNE) and a robust platform for real-time monitoring of single intra-synaptic vesicular release events and of the subsequent generation of postsynaptic membrane excitatory potential (EJP) signals. By using this chip, the first in situ measurements of synaptic transmission in neuro-muscular mimics are reported.

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Homogeneous Catalysis

Nickel-Catalyzed Alkyl–Alkyl Cross-Couplings of Fluorinated Secondary Electrophiles: A General Approach to the Synthesis of Compounds having a Perfluoroalkyl Substituent

Yufan Liang and Prof. Gregory C. Fu

Nickel-Catalyzed Alkyl–Alkyl Cross-Couplings of Fluorinated Secondary Electrophiles: A General Approach to the Synthesis of Compounds having a Perfluoroalkyl SubstituentA new pairing: A mild, convenient, and versatile method for the synthesis of compounds bearing a perfluoroalkyl group on a tertiary carbon atom is described. The title reaction results in the coupling of a wide range of fluorinated alkyl halides with alkylzinc reagents at room temperature. A broad array of functional groups are compatible with the reaction conditions, and preliminary mechanistic studies are discussed. DMA=N,N-dimethylacetamide.

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Mesoporous Catalysts

Ligand-Assisted Co-Assembly Approach toward Mesoporous Hybrid Catalysts of Transition-Metal Oxides and Noble Metals: Photochemical Water Splitting

Dr. Ben Liu, Chung-Hao Kuo, Jiejie Chen, Zhu Luo, Srinivas Thanneeru, Dr. Weikun Li, Wenqiao Song, Sourav Biswas, Prof. Steven L. Suib and Prof. Jie He

Ligand-Assisted Co-Assembly Approach toward Mesoporous Hybrid Catalysts of Transition-Metal Oxides and Noble Metals: Photochemical Water SplittingA bottom-up synthetic approach to mesoporous transition-metal-oxide/noble-metal hybrid catalysts involves the ligand-assisted self-assembly of amphiphilic block-copolymer (BCP) micelles and polymer-tethered noble-metal nanoparticles (NPs). The hybrid catalysts were shown to mediate the photochemical oxidation of water. EISA=evaporation-induced self-assembly.

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Fluoromethylation

Facile Access to Fluoromethylated Arenes by Nickel-Catalyzed Cross-Coupling between Arylboronic Acids and Fluoromethyl Bromide

Lun An, Yu-Lan Xiao, Qiao-Qiao Min and Prof. Dr. Xingang Zhang

Facile Access to Fluoromethylated Arenes by Nickel-Catalyzed Cross-Coupling between Arylboronic Acids and Fluoromethyl BromideEfficient and straightforward: The title reaction is characterized by synthetic simplicity, employing a low-cost nickel catalyst and the industrial raw material CH2FBr as a coupling partner. It enables the late-stage fluoromethylation of biologically relevant molecules. Preliminary mechanistic studies show that a single-electron-transfer pathway is involved in the catalytic cycle. DMAP=4-dimethylaminopyridine, DME=1,2-dimethoxyethane, phen=1,10-phenanthroline.

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Macrocyclization

Acetone-Linked Peptides: A Convergent Approach for Peptide Macrocyclization and Labeling

Dr. Naila Assem, David J. Ferreira, Prof. Dr. Dennis W. Wolan and Prof. Dr. Philip E. Dawson

Acetone-Linked Peptides: A Convergent Approach for Peptide Macrocyclization and LabelingMacrocyclizations are broadly applied for overcoming the intrinsically disordered nature of linear peptides. Dichloroacetone (DCA) enhances helical secondary structures when introduced between peptide nucleophiles, such as thiols, to yield an acetone-linked bridge. The ketone moiety embedded in the linker can be modified with diverse molecular tags by oxime ligation.

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Lab-on-a-Chip

Autonomous Chemical Sensing Interface for Universal Cell Phone Readout

Dr. Germán Comina, Dr. Anke Suska and Prof. Dr. Daniel Filippini

Autonomous Chemical Sensing Interface for Universal Cell Phone ReadoutSmart solution: An autonomous disposable device for quantitative chemical glucose sensing on cell phones was developed. It can operate without permanent accessories, integrates all necessary reagents, calibration and actuation elements, and entails a single design conceived to universally couple to whichever cell phone.

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Cycloaddition

Metal-Free Dehydrogenative Diels–Alder Reactions of 2-Methyl-3-Alkylindoles with Dienophiles: Rapid Access to Tetrahydrocarbazoles, Carbazoles, and Heteroacenes

Liejin Zhou, Bing Xu and Prof. Dr. Junliang Zhang

Metal-Free Dehydrogenative Diels–Alder Reactions of 2-Methyl-3-Alkylindoles with Dienophiles: Rapid Access to Tetrahydrocarbazoles, Carbazoles, and HeteroacenesSetting a trap: Described is a strategy for in situ generation of indole-based ortho-quinodimethanes (oQDMs) from the title indoles through either a DDQ- or BQ-mediated dehydrogenative process. These oQDMs are trapped by electron-deficient olefins, thus providing facile access to tetrahydrocarbazoles, carbazoles, and hetereoacenes. BQ=benzoquinone, DDQ=2,3-dichloro-5,6-dicyano-1,4-benzoquinone.

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Imaging Agents

Cartilage-Specific Near-Infrared Fluorophores for Biomedical Imaging

Prof. Hoon Hyun, Eric A. Owens, Dr. Hideyuki Wada, Andrew Levitz, GwangLi Park, Prof. Min Ho Park, Prof. John V. Frangioni, Prof. Maged Henary and Prof. Hak Soo Choi

Cartilage-Specific Near-Infrared Fluorophores for Biomedical ImagingSeeing red: Near-infrared fluorophores specific for cartilage were synthesized and their performance tested in small and large animal models. These agents not only bind all types of cartilage in all species tested, but they can also be combined with other targeted near-infrared fluorophores, such as those specific to bone, to provide unprecedented biomedical optical imaging.

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Hierarchical Structures

Step-by-Step Growth of Complex Oxide Microstructures

Dr. Panos Datskos, Dr. David A. Cullen and Dr. Jaswinder Sharma

Step-by-Step Growth of Complex Oxide MicrostructuresComplex and hybrid oxide structures were grown by exploiting the emulsion-droplet-based SiO2 deposition. A variety of structures such as corrugated spiky silica structures, a silica ring sandwiched in a particle dimer, and SiO2–TiO2 hybrid structures were synthesized with good control of morphology using the same growth strategy.

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De Novo Design

Fragment-Based De Novo Design Reveals a Small-Molecule Inhibitor of Helicobacter Pylori HtrA

Dr. Anna M. Perna, Dr. Tiago Rodrigues, Thomas P. Schmidt, Dr. Manja Böhm, Katharina Stutz, Daniel Reker, Dr. Bernhard Pfeiffer, Prof. Dr. Karl-Heinz Altmann, Prof. Dr. Steffen Backert, Prof. Dr. Silja Wessler and Prof. Dr. Gisbert Schneider

Fragment-Based De Novo Design Reveals a Small-Molecule Inhibitor of Helicobacter Pylori HtrAThe currently best-in-class inhibitor of Helicobacter pylori HtrA was discovered using fragment-based de novo design and hit expansion. This combination allows to rapidly prototype new chemical entities, and the new inhibitor can be seen as a pioneering tool for chemical biology and potential lead structure for anti-cancer and anti-infective drug discovery.

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Drug Screening

Pim Kinase Inhibitors Evaluated with a Single-Molecule Engineered Nanopore Sensor

Dr. Leon Harrington, Dr. Leila T. Alexander, Prof. Dr. Stefan Knapp and Prof. Dr. Hagan Bayley

Pim Kinase Inhibitors Evaluated with a Single-Molecule Engineered Nanopore SensorUnbiased selection: A kinase inhibitor screening approach was developed that uses a radically different basis of detection than existing methods. Engineered protein nanopores allow the label-free determination of inhibition constants, are scalable to high-throughput, and circumvent biases inherent in prevailing technologies.

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Redox gold catalysis

Ligand-Assisted Gold-Catalyzed Cross-Coupling with Aryldiazonium Salts: Redox Gold Catalysis without an External Oxidant

Rong Cai, Mei Lu, Ellen Y. Aguilera, Yumeng Xi, Dr. Novruz G. Akhmedov, Dr. Jeffrey L. Petersen, Prof. Dr. Hao Chen and Prof. Dr. Xiaodong Shi

Ligand-Assisted Gold-Catalyzed Cross-Coupling with Aryldiazonium Salts: Redox Gold Catalysis without an External OxidantI to III: Gold-catalyzed C(sp)–C(sp2) and C(sp2)–C(sp2) cross-coupling reactions are accomplished with aryldiazonium salts as the coupling partner. With the assistance of the bpy ligand, gold(I) species were oxidized to gold(III) by diazonium without any external oxidants. Monitoring the reaction with NMR and ESI-MS provided strong evidence for the nitrogen extrusion followed by AuIII reductive elimination as the key step.

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Total Synthesis

Total Synthesis of Limonin

Dr. Shuji Yamashita, Dr. Akito Naruko, Yuki Nakazawa, Dr. Le Zhao, Prof. Dr. Yujiro Hayashi and Prof. Dr. Masahiro Hirama

Total Synthesis of LimoninLimonin, not limonene: The flagship congener of the limonoid natural-product family, limonin, was synthesized for the first time. Geraniol was employed as the starting material, and key reactions for the efficient construction of the limonin framework included a tandem radical cyclization, a singlet-oxygen cycloaddition, Baeyer–Villiger oxidation, and a Suárez reaction.

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Photolysis

Next-Generation o-Nitrobenzyl Photolabile Groups for Light-Directed Chemistry and Microarray Synthesis

Nicole Kretschy, Ann-Katrin Holik, Prof. Veronika Somoza, Dr. Klaus-Peter Stengele and Prof. Mark M. Somoza

Next-Generation o-Nitrobenzyl Photolabile Groups for Light-Directed Chemistry and Microarray SynthesisHigh-speed photolysis: The highly light-sensitive groups benzoyl- and thiophenyl-NPPOC (NPPOC=2-(2-nitrophenyl)propoxycarbonyl) were used for light-directed, spatio-selective synthesis. Their photolytic efficiencies are two- and twelvefold greater than that of NPPOC, respectively.

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Conducting Polymers

An Alternative Anionic Polyelectrolyte for Aqueous PEDOT Dispersions: Toward Printable Transparent Electrodes

Anna I. Hofmann, Wiljan T. T. Smaal, Dr. Muhammad Mumtaz, Dr. Dimitrios Katsigiannopoulos, Dr. Cyril Brochon, Falk Schütze, Dr. Olaf R. Hild, Dr. Eric Cloutet and Prof.Dr. Georges Hadziioannou

An Alternative Anionic Polyelectrolyte for Aqueous PEDOT Dispersions: Toward Printable Transparent ElectrodesFlexible and transparent: Polyanions were used to stabilize PEDOT in aqueous dispersions. The highly viscous PEDOT:polyanion dispersions were easily processed into thin, conductive, and transparent films, which could be integrated as transparent electrodes into flexible organic electronic devices.

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Synthetic Methods

Hydroaminomethylation Beyond Carbonylation: Allene–Imine Reductive Coupling by Ruthenium-Catalyzed Transfer Hydrogenation

Susumu Oda, Brannon Sam and Prof. Michael J. Krische

Hydroaminomethylation Beyond Carbonylation: Allene–Imine Reductive Coupling by Ruthenium-Catalyzed Transfer HydrogenationNo CO: Ruthenium(II)-catalyzed hydrogen transfer from 2-propanol mediates reductive coupling of 1,1-disubstituted allenes with formaldimines with complete branch-regioselectivity. This reaction represents a new method for hydroaminomethylation beyond the classical hydroformylation/reductive amination.

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Asymmetric Synthesis

Stereoselective Organocatalytic Synthesis of Oxindoles with Adjacent Tetrasubstituted Stereocenters

Oliver D. Engl, Dr. Sven P. Fritz and Prof. Dr. Helma Wennemers

Stereoselective Organocatalytic Synthesis of Oxindoles with Adjacent Tetrasubstituted StereocentersCrowd around: Oxindoles with adjacent fully substituted stereogenic centers were formed by mild organocatalytic addition reactions with high diastereo- and enantioselectivities. The synthetic versatility of the products with orthogonally addressable functional moieties was showcased in the synthesis of derivatives of the bioactive oxindole AG-041R.

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Surface Chemistry

Size-Dependent Ligand Layer Dynamics in Semiconductor Nanocrystals Probed by Anisotropy Measurements

Ido Hadar, Tsafrir Abir, Shira Halivni, Adam Faust and Prof. Uri Banin

Size-Dependent Ligand Layer Dynamics in Semiconductor Nanocrystals Probed by Anisotropy MeasurementsDynamic properties of a ligand shell: The size-dependent dynamic properties of an organic ligand shell, capping the surface of colloidal nanocrystals, have been studied by probing polarized emission of surface-bound organic dyes (see picture). These properties impact the synthesis, dispersibility, and optoelectronic features of colloidal nanocrystals.

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Synthetic Methods

A Versatile Room-Temperature Route to Di- and Trisubstituted Allenes Using Flow-Generated Diazo Compounds

Jian-Siang Poh, Dr. Duc N. Tran, Dr. Claudio Battilocchio, Dr. Joel M. Hawkins and Prof. Steven V. Ley

A Versatile Room-Temperature Route to Di- and Trisubstituted Allenes Using Flow-Generated Diazo CompoundsWell tolerated: A mild copper-catalyzed coupling reaction between unstabilized diazo compounds (generated in flow) and terminal alkynes is reported. The method provides di- and trisubstituted allenes with high functional-group tolerance.

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Epigenetics

Epigenetic Genome Mining of an Endophytic Fungus Leads to the Pleiotropic Biosynthesis of Natural Products

Dr. Xu-Ming Mao, Dr. Wei Xu, Dr. Dehai Li, Dr. Wen-Bing Yin, Dr. Yit-Heng Chooi, Dr. Yong-Quan Li, Dr. Yi Tang and Dr. Youcai Hu

Epigenetic Genome Mining of an Endophytic Fungus Leads to the Pleiotropic Biosynthesis of Natural ProductsThe endophytic fungus­ Calcarisporium arbuscula is rich in cryptic gene clusters for natural product biosynthesis. Removal of a global epigenetic repressor HdaA, the histone H3 deacetylase, activates the expression of over 75 % of the silenced gene clusters and enables the isolation of new natural products.

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CO2 Activation

Carbon Dioxide Activation and Reaction Induced by Electron Transfer at an Oxide–Metal Interface

Dr. Florencia Calaza, Christian Stiehler, Yuichi Fujimori, Prof. Dr. Martin Sterrer, Sebastian Beeg, Dr. Miguel Ruiz-Oses, Prof. Dr. Niklas Nilius, Dr. Markus Heyde, Teemu Parviainen, Dr. Karoliina Honkala, Prof. Dr. Hannu Häkkinen and Prof. Dr. Hans-Joachim Freund

Carbon Dioxide Activation and Reaction Induced by Electron Transfer at an Oxide–Metal InterfaceElectrons are shuttled back and forth between CO2 and a metal–insulator–metal model system, enabling the activation of CO2 and its reaction to oxalate. This may either react further or reversibly decompose to CO2.

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Polycycles

Tetrabenzoperipentacene: Stable Five-Electron Donating Ability and a Discrete Triple-Layered β-Graphite Form in the Solid State

Akinobu Matsumoto, Dr. Mitsuharu Suzuki, Dr. Daiki Kuzuhara, Dr. Hironobu Hayashi, Prof. Dr. Naoki Aratani and Prof. Dr. Hiroko Yamada

Tetrabenzoperipentacene: Stable Five-Electron Donating Ability and a Discrete Triple-Layered β-Graphite Form in the Solid StateTriple the fun: Synthesis of an all-carbon conjugated tetrabenzoperipentacene was achieved. The single-crystal X-ray structure revealed that the molecules form a triple-layered cluster-like β-graphite. The remarkably rigid carbon framework results in a small Stokes shift and fully reversible five-electron oxidation potentials.

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Prometabolites

Prometabolites of 5-Diphospho-myo-inositol Pentakisphosphate

Igor Pavlovic, Divyeshsinh T. Thakor, Priv.-Doz. Dr. Laurent Bigler, Dr. Miranda S. C. Wilson, Debabrata Laha, Dr. Gabriel Schaaf, Prof. Dr. Adolfo Saiardi and Prof. Dr. Henning J. Jessen

Prometabolites of 5-Diphospho-myo-inositol PentakisphosphatePrecursors of 5-diphospho-myo-inositol pentakisphosphate with biolabile protecting groups were synthesized, and their in vitro/in cellulo metabolism was studied. Acetoxybenzyl phosphates and phosphoanhydrides were rapidly removed in mammalian tissue and cell homogenates. This process was analyzed by polyacrylamide gel electrophoresis, which also led to the identification of unexpected side products.

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Charge Transfer

Carbon Nanodots: Supramolecular Electron Donor–Acceptor Hybrids Featuring Perylenediimides

Volker Strauss, Johannes T. Margraf, Konstantin Dirian, Dr. Zois Syrgiannis, Prof. Dr. Maurizio Prato, Dr. Cordula Wessendorf, Prof. Dr. Andreas Hirsch, Prof. Dr. Timothy Clark and Prof. Dr. Dirk M. Guldi

Carbon Nanodots: Supramolecular Electron Donor–Acceptor Hybrids Featuring PerylenediimidesLong-term separation: Charge-transfer complexes formed by electron-donating carbon nanodots and electron-accepting perylenediimides are prepared. In ultrafast pump-probe experiments (see picture) the charge-separated state with a lifetime of 210 ps was found.

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CO2 Absorption

Computer-Aided Design of Ionic Liquids as CO2 Absorbents

Dzmitry S. Firaha, Dr. Oldamur Hollóczki and Prof. Dr. Barbara Kirchner

Computer-Aided Design of Ionic Liquids as CO2 AbsorbentsBetter by design: Using a continuum model makes it possible to distinguish between the chemical and physical absorption of CO2 in ionic liquids. The ionic liquids showing chemical adsorption were further narrowed down to “good” candidates, in which a facile desorption is feasible according to a calculated energy criterion. This criterion was determined by correlating the calculated Gibbs free energies with experimental capacities.

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