Total Synthesis of α-Tocopherol through Enantioselective Iridium-Catalyzed Fragmentation of a Spiro-Cyclobutanol Intermediate

Activation time! The asymmetric fragmentation of a spiro[chromane-2,3′-cyclobutanol] proceeds smoothly and with high levels of stereocontrol in the presence of a chiral iridium catalyst. This opened a new strategy for the (2R)-selective synthesis of α-tocopherol (i.e., vitamin E).

[Communication]

Friederike Ratsch, Dr. Waldemar Schlundt, Dominik Albat, Anne Zimmer, Dr. Jörg-Martin Neudörfl, Dr. Thomas Netscher, Prof. Dr. Hans-Günther Schmalz

doi.org/10.1002/chem.201900564

A Modular Ligation Strategy for Asymmetric Bivalent Nucleosomes Trimethylated at K36 and K27

Access all areas: Asymmetric nucleosomes are a key feature of stem cell chromatin. Here a modular and traceless chemical strategy to control the supramolecular assembly of bivalent nucleosomes asymmetrically modified at K27 and K36, is described. It is shown that the trimethylation of K36 hinders PRC2 activity while extending its binding time to chromatin fibers.

[Minireview]

Nora Guidotti, Dr. Carolin C. Lechner, Dr. Andreas L. Bachmann, Dr. Beat Fierz

doi.org/10.1002/cbic.201800744

Rational Structure-Based Design of Fluorescent Probes for Amyloid Folds

Amyloid fibrils are hallmark of various diseases. Here, small molecular fluorescent probes are reported that selectively recognize amyloid beta(1-42), α-synuclein, and HET-s(218-289) fibrils. The rational design of the fluorophore relies on the well-known cross-β-sheet repetition motif.

[Minireview]

Dr. Julien Orts, Dr. Marielle Aulikki Wälti, Dr. Dhiman Ghosh, Dr. Silvia Campioni, Dr. Sven J. Saupe, Prof. Roland Riek

doi.org/10.1002/cbic.201800664

Leather-Promoted Transformation of Glucose into 5-Hydroxymethylfurfural and Levoglucosenone

Heaven for leather: Leather acts as a heterogeneous catalyst in which chromium ions are immobilized on collagen. Specifically, waste chromium-tanned leather is used to catalyze the transformation of D-glucose into levoglucosenone and 5-hydroxymethylfurfural in DMSO at 165 °C.

[Full Paper]

Dr. Felix D. Bobbink, Dr. Zhangjun Huang, Florent Menoud, Prof. Paul J. Dyson

doi.org/10.1002/cssc.201802830

Tuning the Fluorescence Emission and HOMO-LUMO Band Gap in Homoleptic Zinc(II) Complexes with N,O-Bidentate (Imidazo[1,5-a]pyrid-3-yl)phenols

A series of homoleptic zinc(II) complexes with N,O-imidazo-pyridine ligands is presented. They show an intense fluorescence emission in solution, with high Stokes shifts and quantum yields. Besides, λ_max is tunable by the electronic features of the substituent R at the para position of the bound-to-zinc hydroxyl group.

[Full Paper]

G. Attilio Ardizzoia, Gioele Colombo, Bruno Therrien, Stefano Brenna

doi.org/10.1002/ejic.201900067

Hidden Specificities in Enzyme Catalysis: Structural Basis of Substrate Structure-Selectivity Relationship of a Ketoreductase

A secret life: Enzymatic reactions are often considered highly specific with each enzyme being responsible for a stereoselective conversion of a particular substrate. The polyketide synthase reductase Tyl-KR1, however, has a hidden second specificity that catalyzes reductions of β-ketoesters to S,S-configured products instead of the physiologically observed R,R. Which specificity applies, depends on subtle modifications on the substrate.

[Minireview]

Dr. Matthias Häckh, Dr. Xavier Lucas, Dr. Marija Marolt, Prof. Dr. Peter F. Leadlay, Prof. Dr. Michael Müller, Prof. Dr. Stefan Günther, Dr. Steffen Lüdeke

doi.org/10.1002/cbic.201800799

Kinetic Competition between Water-Splitting and Photocorrosion Reactions in Photoelectrochemical Devices

Predicting longevity: Semiconductor photocorrosion is a major challenge for the stability of photoelectrochemical water-splitting devices. A kinetic model to describe detailed reaction mechanisms and competition between water-splitting and photocorrosion reactions is provided and reveals that the photostability of a semiconductor mainly depends on surface chemical properties, catalyst activity, charge carrier density, and electrolyte acidity.

[Full Paper]

Dr. Fredy Nandjou, Prof. Sophia Haussener

doi.org/10.1002/cssc.201802558

A Substantial Structural Conversion of the Native Monomer Leads to in-Register Parallel Amyloid Fibril Formation in Light-Chain Amyloidosis

Deposit account: Amyloid light-chain amyloidosis is a rare and deadly disease in which immunoglobulin light chains deposit in vital organs. The molecular details of this process, as well as the structures of the fibrils, are unknown. Here, with the aid of solid-state NMR data, we reveal the secondary structures and their arrangement into parallel in-register sheets.

[Minireview]

Dr. Lauriane Lecoq, Dr. Thomas Wiegand, Dr. Francisco J. Rodriguez-Alvarez, Riccardo Cadalbert, Prof. Guillermo A. Herrera, Prof. Luis del Pozo-Yauner, Prof. Beat H. Meier, Dr. Anja Böckmann

doi.org/10.1002/cbic.201800732

Improvement of Aglycone π-Stacking Yields Nanomolar to Sub-nanomolar FimH Antagonists

Urinary tract infections caused by uropathogenic E. coli are common bacterial infections. Due to antibiotic resistance, new treatment options are needed. Targeting the adhesin FimH with glycomimetic antagonists prevents adhesion to the bladder. Herein we report novel compounds with unprecedented affinity to the biologically relevant conformation of FimH. The affinity gain is enabled by extensive π-stacking interactions of the biphenyl aglycone to Tyr48.

[Full Paper]

Dr. Wojciech Schönemann, Dr. Jonathan Cramer, Tobias Mühlethaler, Dr. Brigitte Fiege, Marleen Silbermann, Dr. Said Rabbani, Dr. Philipp Dätwyler, Dr. Pascal Zihlmann, Dr. Roman P. Jakob, Dr. Christoph P. Sager, Dr. Martin Smieško, Dr. Oliver Schwardt, Prof. Dr. Timm Maier, Prof. Dr. Beat Ernst

doi.org/10.1002/cmdc.201900051

Controlled Synthesis of Surfactant-Free Water-Dispersible Colloidal Platinum Nanoparticles by the Co4Cat Process

Go for colloids: The Co4Cat process is a simple method to produce colloidal dispersions of precious-metal nanoparticles with controlled properties in alkaline mono-alcohols. The obtained Pt nanoparticles show long-term dispersibility in water and aqueous buffers.

[Full Paper]

Dr. Jonathan Quinson, Laura Kacenauskaite, Jan Bucher, Dr. Søren B. Simonsen, Dr. Luise Theil Kuhn, Prof. Dr. Mehtap Oezaslan, Dr. Sebastian Kunz, Prof. Dr. Matthias Arenz

doi.org/10.1002/cssc.201802897

Deactivation of Methanation Catalyst (Ru/C) Under Supercritical Water by Deposition of Non-Volatile Organics: First Insights Into Deposition Patterns and Chemical Properties

The deactivation of Ru/C methanation catalyst by fouling was investigated using complementary analytical tools. We could show that the extraction using a mixture of organic solvents of used, but still active, catalyst is sufficient to restore the full activity of the catalyst. The morphology of organic deposits was investigated using small-angle scattering and first insight into the chemical composition using high-resolution mass spectrometry.

[Full Paper]

Dr. Saša Bjelić, Prof. Dr. Urs Gasser, Dr. Ivo Alxneit, Prof. Dr. Frédéric Vogel

doi.org/10.1002/cctc.201801615

Quantitative Assessment of Affinity Selection Performance by Using DNA-Encoded Chemical Libraries

Binding targets: The performance of affinity selection procedures in DNA-encoded chemical libraries (DECL) sets limits on the recovery rates and selectivity of high- and low-affinity ligands. This work provides a systematic quantification of DNA binders in the context of model and real library selections by using quantitative PCR and DNA sequencing methodologies.

[Minireview]

Alessandro Sannino, Dr. Elena Gabriele, Martina Bigatti, Dr. Sara Mulatto, Dr. Jacopo Piazzi, Dr. Jörg Scheuermann, Prof. Dr. Dario Neri, Dr. Etienne J. Donckele, Dr. Florent Samain

doi.org/10.1002/cbic.201800766

On-Site Purification of Copper-Contaminated Vanadium Electrolytes by using a Vanadium Redox Flow Battery

Let it flow: Carbon corrosion in a commercial vanadium redox flow battery enables the electrolyte to leach the copper current collectors, contaminating the entire electrolyte solution. A procedure to identify copper contamination on site and to purify the electrolyte was developed and used to purify large quantities (6000 L) of contaminated electrolyte.

[Full Paper]

Danick Reynard, Heron Vrubel, Christopher R. Dennison, Alberto Battistel, Prof. Hubert Girault

doi.org/10.1002/cssc.201802895

Visible Light Photoredox Catalysis Using Ruthenium Complexes in Chemical Biology

Let there be light: The use of photoredox catalysis with ruthenium complexes in chemical biology is reviewed. A unique and attractive property of ruthenium photocatalysts is their ground-state stability coupled to their photoexcited state reactivity. The fact that the catalyst is activated by light provides control of the reactivity in space and time.

[Communication]

Simona Angerani, Prof. Dr. Nicolas Winssinger

doi.org/10.1002/chem.201806024

Is Iron the New Ruthenium?

Long-lived replacements: Ruthenium complexes with polypyridine ligands are very popular choices for applications in photophysics and photochemistry, but ruthenium is rare and expensive, whereas iron is comparatively abundant and cheap. Key concepts to obtain long-lived charge-transfer excited states in iron complexes (see figure) are discussed and recent conceptual breakthroughs are highlighted.

[Communication]

Prof. Dr. Oliver S. Wenger

doi.org/10.1002/chem.201806148

Slow Formation of Pseudorotaxanes in Water

Kinetically inert and thermodynamically stable pseudorotaxanes with slow formation kinetics in water are developed. The substitution pattern of the hydrophilic end-group of rigid OPE axles controls the association kinetics with a Diederich-type cyclophane.

[Full Paper]

Yves Aeschi, Laurent Jucker, Daniel Häussinger, Marcel Mayor

doi.org/10.1002/ejoc.201801864

Helicenes as Chiroptical Photoswitches

A rare gem: Known helicene systems that function as chiroptical photoswitches are analyzed from a stereochemical perspective. Reported examples are classified into three types based on the type of transformation of the helicene core that takes place during the switching process.

[Article]

Dr. Prince Ravat, Dr. Tomáš Šolomek, Prof. Michal Juríček

doi.org/10.1002/cptc.201800229

Hydride Formation Diminishes CO₂ Reduction Rate on Palladium

Hydride formation, as followed gravimetrically upon hydrogen absorption from H₂/CO₂, diminishes the catalytic performance of CO₂ reduction.

[Communication]

Emanuel Billeter, Jasmin Terreni, Dr. Andreas Borgschulte

doi.org/10.1002/cphc.201801081

Scaling Up Electrodes for Photoelectrochemical Water Splitting: Fabrication Process and Performance of 40 cm² LaTiO₂N Photoanodes

Go big or go home: A scalable process for fabrication of particle-based electrodes for solar water splitting is developed. Demonstrator-size photoanodes exhibit complex performance changes related to the electrode size. Scale up of photoelectrochemically active electrodes needs careful consideration with respect to size and device geometry.

[Full Paper]

Dr. Stefan Dilger, Matthias Trottmann, Prof. Simone Pokrant

doi.org/10.1002/cssc.201802645

The Emerging Role of Tetrazines in Drug-Activation Chemistries

Getting pro(drug)active: Bioorthogonal chemistry has transformed the field of prodrug activation. In particular, the inverse electron demand Diels Alder reaction has gained attention due to its high reaction rates and biocompatibility. This article discusses the concept of using tetrazines as an activator for prodrugs, and provides an overview of tetrazine-based prodrug systems.

[Minireview]

Dr. Kevin Neumann, Alessia Gambardella, Prof. Mark Bradley

doi.org/10.1002/cbic.201800590

Aerobic Oxidation of Methyl-substituted β-Carbolines Catalyzed by N-Hydroxyphthalimide and Metal Catalyst

Carboxylic functionalized β-carbolines have been synthesized in good to excellent yields and high selectivity by oxygen in the presence of NHPI and transition metal salt under mild conditions

[Communications]

Hongda Qiu, Weida Liang, Dr. Gongjun Zhang, Miaoman Lin, Wanmin Liu, Prof. Zhanghua Gao, Dr. Wenting Wei, Dr. Chunlan Tang, Dr. Haixiao Jin, Prof. Hongze Liang, Prof. Xiaojun Yan

doi.org/10.1002/slct.201803007

Copper Catalyzed Direct Synthesis of Nitriles from Acyl Azides

A novel and general protocol for the copper catalyzed reductive elimination of acyl azides to nitriles using triethoxysilane is reported. Various nitriles are obtained in moderate to excellent yields with good functional group tolerance and high chemoselectivity.

[Communications]

Prof. Yang Chen, Yu Liu, Xiao Zhang, Da Lu, Lixin Yang, Junfeng Deng, Prof. Shengqi Deng

doi.org/10.1002/slct.201802918