Article
Chemistry, Multidisciplinary
Francesco Ferlin, Ioannis Anastasiou, Nihad Salameh, Takeru Miyakoshi, Olivier Baudoin, Luigi Vaccaro
Summary: A heterogeneous catalyst has been prepared for the intramolecular activation/cyclization reaction to synthesize indolines. The catalyst showed high efficiency through a release and catch mechanism, facilitated by iodide ligands. The heterogeneous nature of the catalyst was further utilized in the design of a continuous-flow protocol, enabling efficient recovery and reuse.
Article
Chemistry, Physical
Bijan Mirabi, Austin D. Marchese, Mark Lautens
Summary: In this study, a nickel-catalyzed cross-electrophile coupling reaction of aryl chlorides and heteroaryl chlorides was reported, enabled by a synergistic combination of halide effects and the addition of a magnesium salt. Electronic-deficient aryl chlorides were found to perform the best in the reaction, and preliminary mechanistic evidence showed that MgCl2 is crucial for accelerating the reduction of Ni(II) while small quantities of iodide lead to improved yields.
Article
Chemistry, Organic
Fang Wang, Qianting Zhou, Xinying Zhang, Xuesen Fan
Summary: A novel and efficient alpha-C(sp(3))-H alkenylation of cyclic amines with maleimides was presented, featuring readily available and structurally diverse substrates, a green and economical catalyst, a unique reaction pathway, mild reaction conditions, high efficiency, and excellent atom economy. This new reaction enriches the application of Fe(III)-catalyzed C(sp(3))-H activation and functionalization.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Ji-Hang Xu, Zi-Kui Liu, Yan-Liu Tang, Yang Gao, Xiao-Qiang Hu
Summary: An unprecedented ring-opening cross-coupling of 1,2-oxazetidines with arylboronic acids using copper catalysis has been achieved. This reaction offers simple operation, inexpensive catalyst, broad scope, and high regioselectivity, leading to a wide range of aminomethylation products. Furthermore, the obtained products can be further transformed and bioactive acids can be modified.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Igor Beckers, Besir Krasniqi, Prashant Kumar, Daniel Escudero, Dirk De Vos
Summary: Two indoles linked by a C-C bond have emerged as promising scaffolds in medicinal chemistry. In this study, selective C-H/C-H cross-coupling of N-substituted indoles without directing groups was achieved under mild conditions, driven by molecular oxygen. The ligand-controlled selectivity can be exploited to achieve selective cross-coupling between two indoles with different substitution patterns.
Review
Chemistry, Multidisciplinary
Jianbin Li, Chia-Yu Huang, Chao-Jun Li
Summary: This review summarises recently developed strategies for achieving C-C cross-couplings between an inert aliphatic C-H bond and another C-H bond through different C(sp3)-H functionalisation tactics.
TRENDS IN CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Xiang-Ting Min, Ding-Wei Ji, Yu-Qing Guan, Shi-Yu Guo, Yan-Cheng Hu, Boshun Wan, Qing-An Chen
Summary: Transition metal catalyzed decarbonylation offers a unique synthetic strategy for new chemical bond formation. The study developed a visible light induced rhodium catalysis for decarbonylative coupling of imides with alkynes under ambient conditions, revealing the rhodium complex serves as both the catalytic center and photosensitizer. This visible light promoted catalytic decarbonylation strategy opens up new opportunities for re-evaluating old transformations with ligand dissociation as a rate-determining step.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Cristian Cavedon, Sebastian Gisbertz, Susanne Reischauer, Sarah Vogl, Eric Sperlich, John H. Burke, Rachel F. Wallick, Stefanie Schrottke, Wei-Hsin Hsu, Lucia Anghileri, Yannik Pfeifer, Noah Richter, Christian Teutloff, Henrike Mueller-Werkmeister, Dario Cambie, Peter H. Seeberger, Josh Vura-Weis, Renske M. van der Veen, Arne Thomas, Bartholomaus Pieber
Summary: We demonstrate visible-light-mediated carbon-heteroatom cross-coupling reactions using a photoactive Ni(II) precatalyst. The activation of this precatalyst involves an initial intraligand charge transfer event triggered by visible light irradiation. Additionally, a porous, recyclable organic polymer for heterogeneous nickel catalysis of cross-coupling reactions is obtained through ligand polymerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Organic
C. M. A. Afsina, Thaipparambil Aneeja, Mohan Neetha, Gopinathan Anilkumar
Summary: Copper-catalyzed organic reactions have attracted widespread attention due to the abundance and affordability of copper, as well as its low toxicity, eco-friendliness, sustainable nature, and versatility as a catalyst. These reactions are primarily used for the synthesis of biologically important nitrogen heterocycles, amines, amides, imines, and alkynes.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Wei Wei, Xiaodan Zhao
Summary: The carbon-carbon bond-forming cross-dehydrogenative coupling reaction using organoselenium catalysis involving a high-valent para-methoxyphenyl selenium species has been developed. This method enables the synthesis of alpha,alpha-disubstituted alpha-amino acid derivatives with excellent regioselectivities through vinyl or allylic C-H functionalization. The generality of this method has been demonstrated by the cross-coupling of an alkene with an oxindole and the direct functionalization of electron-rich arenes with azlactones.
Article
Chemistry, Organic
Jakub Brzeskiewicz, Barbara Stanska, Piotr Dabrowski, Rafal Loska
Summary: The palladium-catalyzed activation of C(sp(2))-H bond in an easily E,Z-isomerizable aldonitrone with an ester group at the C terminus enabled its cross-coupling with various aryl and heteroaryl bromides to produce ketonitrones. The reactions exhibited high E selectivity and the use of sterically hindered carboxylic acid as an additive, along with a non-polar solvent like toluene, was crucial for achieving good yields of the cross-coupling products. The obtained ketonitrones were further shown to be useful in dipolar cycloaddition or nucleophilic addition reactions.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Mo Chen, John Montgomery
Summary: Regio- and enantioselective functionalization of heteroarene C-H bonds in the absence of directing groups has been a long-standing challenge. In this study, we developed a new approach for intermolecular enantioselective C-H alkylation of heteroarenes using nickel catalysts. The reaction can be carried out under mild conditions without the need for Lewis acid co-catalysts. Synthesis of NHC nickel complexes stabilized with 1,5-hexadiene improved the functional group tolerance and heteroarene scope. Mechanistic investigations revealed a ligand-to-ligand hydrogen transfer pathway.
Article
Chemistry, Multidisciplinary
Nihad Salameh, Federica Valentini, Olivier Baudoin, Luigi Vaccaro
Summary: We report a general and efficient enantioselective C-H arylation of aryl bromides using BozPhos as the bisphosphine ligand and SP-NHC-PdII as recoverable heterogeneous catalyst. By exploiting the release and catch mechanism of action, high enantioselectivities were achieved across different substrates containing methyl, cyclopropyl and aryl C-H bonds. The developed catalytic system provides a more sustainable solution for the synthesis of high added-value chiral products through recycling of the precious metal.
Article
Chemistry, Organic
Xiao-Wen Wang, Rui-Xue Li, Yang Deng, Ming-Qiu-Hao Fu, Ya-Nan Zhao, Zhi Guan, Yan-Hong He
Summary: This article proposes a new method for the direct hydroxylarylation of unactivated benzylic carbons (sp3/sp2/sp) without the need for pre-functionalized benzylic alcohols, aromatic aldehydes, or ketones. It features direct functionalization of unactivated benzylic C(sp3)-H bonds and benzylic sp2/sp-carbons, mild conditions (open air, room temperature), an environmentally friendly procedure (without any external catalyst/mediator/additive), and direct access to sterically hindered alcohols from inexpensive and readily available alkyl/alkenyl/alkynylbenzenes. Mechanistic studies strongly support the proposed radical-radical cross-coupling between transient ketyl radicals and persistent radical anions. Gram-scale synthesis and diversification of drug derivatives demonstrate the practical potential of this protocol.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Jan Ulc, Jaroslav Jacko, Ivana Cisarova, Lubomir Pospisil, David Necas, Martin Kotora
Summary: Here, the design and synthesis of a series of novel cationic nitrogen-embedded polyaromatic hydrocarbons with a planar geometry are reported. The synthesis pathway is based on catalytic C-C/C-H bond activation relay, enabling the preparation of selectively-regioselective 5,6,10,11-tetrasubstituted naphtho[2,1,8-ija]quinolizinium salts with various substituents. Single-crystal X-ray analysis confirmed the planarity of the quinolizinium core. Most of the synthesized compounds exhibited strong fluorescence, ranging from 420-600 nm, depending on the substitution pattern. DFT calculations revealed that the LUMO is always distributed over the quinolizinium framework while the delocalization of HOMO is related to the substitution pattern. Electrochemical measurements showed irreversible reduction of all compounds, which is consistent with the calculated location of LUMO orbitals.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Thomas Linder, Eleni Papaplioura, Diyana Ogurlu, Sophie Geyrhofer, Scarlet Hummelbrunner, Daniel Schachner, Atanas G. Atanasov, Marko D. Mihovilovic, Verena M. Dirsch, Michael Schnuerch
Summary: NF-kappa B inhibitors play a crucial role in inflammation treatment. Through the modification of leoligin, we found that variations in ester functionality and substituents on the tetrahydrofuran scaffold significantly influence the biological activity.
Letter
Chemistry, Multidisciplinary
Olga Lanaridi, Sonja Platzer, Winfried Nischkauer, Jokin Hidalgo Betanzos, Ainhoa Unzurrunzaga Iturbe, Carmen Del Rio Gaztelurrutia, Laura Sanchez-Cupido, Amal Siriwardana, Michael Schnuerch, Andreas Limbeck, Thomas Konegger, Katharina Bica-Schroeder
Summary: The recovery of platinum group metals (PGMs) is of critical importance due to the depletion of natural resources and increasing demand. This study presents a process using benign deep eutectic solvents (DESs) for PGM extraction from spent car catalysts, demonstrating their effectiveness as leaching media.
GREEN CHEMISTRY LETTERS AND REVIEWS
(2022)
Article
Chemistry, Organic
Cornelia S. Buettner, Michael Schnu, Katharina Bica-Schroeder
Summary: This research presents a visible light-catalyzed hydroalkylation reaction of aryl-alkenes with alkyl iodides. The reaction demonstrates high yields of various hydroalkylation products, tolerating primary, secondary, and tertiary alkyl iodides. Mechanistic experiments reveal the pathway of halogen atom transfer followed by a radical-polar crossover mechanism.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Kristof Stagel, Andrea Szpecht, Dawid Zielinski, Marcin Smiglak, Michael Schnuerch, Katharina Bica-Schroeder
Summary: This article presents a novel approach for the halide-free, continuous-flow preparation of hydrophobic ionic liquids (ILs) using bis(trifluoromethanesulfonyl)imide (NTf2-) anion. The methodology offers a simple yet fast two-step synthetic route with high yields and excellent purities. The variable alkyl chain length and a wide range of applicable nucleophiles provide flexibility to the synthetic protocol. This approach has the potential to be a fast and efficient alternative to conventional synthesis methods, with reduced waste water production and broader application range in materials science.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Biochemistry & Molecular Biology
Katharina Obleser, Hubert Kalaus, Bernhard Seidl, Martin Kozich, Christian Stanetty, Marko D. Mihovilovic
Summary: Laccases are environmentally friendly enzymes that provide a green alternative to traditional alcohol oxidation protocols. However, they require mediator molecules to facilitate electron transfer, and there is a lack of comparable data in this field. This study conducted a time-resolved, quantitative screening of laccase and mediator using anis alcohol oxidation as a model reaction. The researchers measured the redox potentials of mediators under the reaction conditions to optimize the mediator-assisted laccase catalyzed oxidations.
Article
Chemistry, Organic
Johanna Templ, Edma Gjata, Filippa Getzner, Michael Schnuerch
Summary: In this study, we used phenyl trimethylammonium iodide as a reagent to achieve highly selective methylation of amides and indoles. The method is easy to use, provides high yields, has good functional group tolerance, and is particularly suitable for late-stage methylation of bioactive compounds.
Article
Chemistry, Applied
Philipp Miksovsky, Elias N. Horn, Shaghayegh Naghdi, Dominik Eder, Michael Schnuerch, Katharina Bica-Schroeder
Summary: In this article, a continuous flow method using carbon dioxide in its supercritical state as a solvent and reagent is presented for the conversion of bioderived limonene oxide and limonene dioxide to limonene carbonates. The best-performing catalyst, tetrabutylammonium chloride, is physisorbed on mesoporous silica and used in continuous flow. The surface area and pore size distribution of the supported ionic liquid phase (SILP) catalysts are analyzed, and the long-term behavior of the SILP system is studied. The yield of the desired product is found to be 16% for limonene oxide and 17% for limonene dioxide.
ORGANIC PROCESS RESEARCH & DEVELOPMENT
(2022)
Article
Chemistry, Organic
Raheleh Pourkaveh, Maren Podewitz, Michael Schnuerch
Summary: Here we report a rhodium-catalyzed Fujiwara-Moritani-type reaction of unactivated terminal alkenes and benzoic acid derivatives bearing electron donating residues under mild conditions. The acid functionality acts as a traceless directing group delivering products alkenylated in meta-position to the electron donating substituent. The new C-C bond is formed to the C2 of the terminal olefin, in contrast to similar reported transformations. Initial mixtures of exo- and endo-double bond isomers can be efficiently isomerized to the more stable endo-products.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Review
Biochemistry & Molecular Biology
Aitor Sainz Martinez, Olga Lanaridi, Kristof Stagel, Heidi Halbwirth, Michael Schnuerch, Katharina Bica-Schroeder
Summary: Cannabis has a long history and was widely used for various purposes in the past, including textiles, feed, and medicine. Although its cultivation declined, non-intoxicating cannabinoids like CBD and CBN have recently gained popularity. Over 10,000 research articles about cannabis are published annually. This review provides an overview of its history, classification, chemical characteristics, and focuses on the extraction of bioactive compounds from cannabis, concluding with future research directions.
NATURAL PRODUCT REPORTS
(2023)
Article
Chemistry, Physical
Kristof Stagel, Adam Mark Palvoelgyi, Clemence Delmas, Michael Schnuerch, Katharina Bica-Schroeder
Summary: We introduced a new approach for continuous-flow allylic alkylation of N-nucleophiles using Pd-complex-containing supported ionic liquid phases (SILPs). This immobilization strategy provided easy access to catalyst frameworks tolerant to air, allowing rapid and convenient synthesis of various achiral and chiral N-allylation products. The optimized conditions allowed for a 3.5-hour flow-reaction with constant product output, while showing minimal leaching of the ionic liquid (0.7 wt %) and no detectable leaching of palladium-complex.
Article
Chemistry, Multidisciplinary
Blanca Angelica Vega Alanis, Laurin Wimmer, Margot Ernst, Michael Schnuerch, Marko D. Mihovilovic
Summary: The synthesis of novel pyrazolothienopyridinone derivatives as potential GABA(A) receptor modulators was achieved through two different synthetic strategies, resulting in a set of 8 target compounds.
MONATSHEFTE FUR CHEMIE
(2023)
Article
Chemistry, Multidisciplinary
Johanna Templ, Michael Schnuerch
Summary: This study presents a novel solvent-free, mechanochemical protocol for the palladium-catalyzed Tsuji-Trost allylation. The approach exhibits advantages such as low catalyst loadings, short reaction times, and a simple setup, without the need for air or moisture precautions, making it highly efficient and environmentally friendly. The introduction of solid, nontoxic, and easy-to-handle allyl trimethylammonium salts as alternative reagents provides a valuable option to replace volatile or hazardous reagents. The mild conditions and exceptional functional group tolerance of this approach enable the allylation of various O-, N-, and C-nucleophiles in yields up to 99%, even for structurally complex bioactive compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Nanditha Kattukudiyil Narayanan, Ernst Pittenauer, Michael Schnuerch
Summary: Here, a ruthenium-catalyzed ketone directed ortho-arylation is described, in which the addition of a bidentate NC-type ligand, particularly 2-(o-tolyl) pyridine, significantly enhances the C-H arylation reaction. Various aryl-alkyl ketones are competent substrates, and arylboronic acid esters are used as aryl sources. However, substitution with OMe and CF3 in the aromatic ring of the ketone substrates is not tolerated.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Nadja K. Singer, Katharina Schloegl, J. Patrick Zobel, Marko D. Mihovilovic, Leticia Gonzalez
Summary: Understanding the thermal isomerization mechanism of azobenzene derivatives is crucial for designing photoswitches with adjustable half-lives. Through quantum chemical calculations, nonadiabatic transition state theory, and photosensitized experiments, we unravel the thermal Z/E isomerization of a heteroaromatic azoswitch, phenylazo-1,3,5-trimethylpyrazole, and predict two pathways at room temperature, involving different reaction mechanisms and spin-orbit couplings.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Organic
Adam Mark Palvoelgyi, Florian Ehrschwendtner, Michael Schnuerch, Katharina Bica-Schroeder
Summary: We have successfully developed a photocatalyst- and additive-free radical hydroacylation reaction under mild reaction conditions. By utilizing 4-acyl-Hantzsch ester radical reservoirs, various substrates including Michael acceptors, enones, and para-quinone methides can be reacted. This protocol allows for further derivatizations and can also be extended to unactivated alkenes. Furthermore, the nature of the radical process has been investigated.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
