Article
Chemistry, Multidisciplinary
Dong-Tai Xie, Hong-Lei Chen, Dian Wei, Bang-Yi Wei, Zheng-Hu Li, Jian-Wu Zhang, Wei Yu, Bing Han
Summary: A novel distal radical rearrangement of alkoxyphosphine is developed for the first time and applied to the regioselective radical fluoroalkylphosphorylation of unactivated olefins. By employing a one-pot two-step reaction under CFL (compact fluorescence light) irradiation, a series of fluoroalkylphosphorylated alkyl iodides and alcohols are easily synthesized.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Bi-Hong Chen, Yi-Dan Du, Wei Shu
Summary: Herein, a metal-free photocatalytic regioselective C-H alkylation method for electron-rich arenes with both activated and unactivated alkenes was developed, providing a general and straightforward metalfree approach for C-C bond formation from inert C-H bonds. The reaction tolerates a wide range of aromatic rings with diverse substitution patterns, as well as terminal and internal alkenes, and is also compatible with alkynes for C-H vinylation of electron-rich arenes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Shubham Dutta, Akhila K. K. Sahoo
Summary: This paper describes a Pd-catalyzed three-component syn-1,2-arylmethylation method, which successfully synthesizes methyl-containing tetra-substituted olefins by using readily available and stable coupling partners iodo-arenes and methyl boronic acid. The reaction shows a broad scope with excellent functional-group tolerance and exhibits remarkable regio- and stereoselectivity. Biologically relevant motifs (BRM) bearing iodo-arenes and ynamides are also used for late-stage syn-1,2-arylmethylation of alkynes. Additionally, aryl-alkylation, aryl-trideuteriomethylation, alkynyl-methylation, and alkenyl-methylation of ynamides are presented, leading to the synthesis of synthetically important beta-amino-indenones and alpha-fluoro-alpha '-methyl ketones.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Sangeth Jenthra, Totan Mondal, Gregor Kemper, Marcus Lantzius-Beninga, Markus Hoelscher, Walter Leitner
Summary: A highly chemo- and regioselective decarboxylative Heck-type coupling of carboxylic acids and terminal olefins was achieved using a catalytic system composed of Pd(OAc)(2) in the presence of phosphine-sulfonamido ligands. The bulky ligand L1 favored the formation of 1,1-disubstituted branched olefins with high selectivity, while the less bulky ligand L2 resulted in the formation of 1,2-disubstituted linear products in high yield. Detailed mechanistic investigation revealed that the aryl substituent at the sulfonamide group of ligand L1 favored 1,2-insertion, while the less bulky ligand L2 favored 2,1-insertion.
Article
Chemistry, Organic
Sheng Zhang, Hao Zhang, Zhuang-Ping Zhan
Summary: A highly efficient hydroallylation reaction of 1,3-diynes with allylborons was developed, with the regioselectivity governed primarily by the appropriate choice of the metal. A series of unsymmetrical and symmetrical 1,3-diynes could undergo this transformation leading to the switch of two regioselective allyl-functionalized 1,3-enynes when palladium and nickel bearing easily available phosphorus ligands were respectively employed.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Organic
Subhankar Ghosh, Shital K. Chattopadhyay
Summary: In this study, a single metal catalyst and air as the oxidant were used to achieve tandem C-H arylation and C-H amidation of cis-cinnamyl hydroxamates, leading to the regioselective formation of a 3-aryl-2-quinolone ring system. Under identical conditions, the corresponding trans-isomer resulted in a 4-aryl-2-quinolone derivative. The observed complementary regioselectivity during the tandem C-H arylation and C-H amidation of isomeric substrates is unusual and has potential applications.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Jianxiao Li, Chenjing Hong, Yanan Niu, Bowen Wang, Wenfang Xiong, Huanfeng Jiang
Summary: A novel and reliable palladium-catalyzed oxylallylation reaction was developed for the synthesis of gem-difluorinated isoxazole derivatives. This strategy enables the direct combination of isoxazole motifs and gem-difluoroalkene units, which is challenging to achieve through conventional synthetic methods. The reaction proceeded with high atom- and step-economy and excellent functional group compatibility, providing structurally diverse products in moderate to good yields.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Joshua T. Gavin, Roman G. Belli, Courtney C. Roberts
Summary: Radical-polar crossover mechanisms are commonly used in late transition metal and photocatalyzed reactions, but reductive radical-polar crossover mechanisms have not been proposed for group 3 early transition metals. By using a redox-active (tris)amido ligand, we have successfully accessed this mechanism for early transition metals. This mechanism enables the formation of various elimination products from alpha-halo substituted benzylic bromides, and Hammett analysis reveals the presence of an anionic intermediate. Furthermore, the wide tolerance of functional groups in this reaction is demonstrated.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Lijun Shi, Mingshan Wen, Fuwei Li
Summary: The study reports a selective method for the synthesis of fused N-heterocycles through palladium-catalyzed tandem reactions, which successfully addresses the selectivity issue in the presence of incompatible step reactions and effectively prevents side reactions.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Multidisciplinary Sciences
Xiaoyang Huang, Ouardia Akdim, Mark Douthwaite, Kai Wang, Liang Zhao, Richard J. Lewis, Samuel Pattisson, Isaac T. Daniel, Peter J. Miedziak, Greg Shaw, David J. Morgan, Sultan M. Althahban, Thomas E. Davies, Qian He, Fei Wang, Jile Fu, Donald Bethell, Steven McIntosh, Christopher J. Kiely, Graham J. Hutchings
Summary: This study demonstrates that the reaction rate can be almost doubled by separating the gold and palladium components in bimetallic carbon-supported catalysts. The enhancement is attributed to the coupling of separate redox processes occurring at isolated gold and palladium sites.
Article
Chemistry, Organic
Tom J. M. Byrne, Megan E. Mylrea, James D. Cuthbertson
Summary: This article describes a simple and efficient strategy for synthesizing substituted tetrahydrofurans from readily available cis-butene-1,4-diol. A redox-relay Heck reaction is used to quickly obtain cyclic hemiacetals, which can be directly reduced to obtain the corresponding 3-aryl tetrahydrofuran. Furthermore, these hemiacetals can also serve as precursors to a variety of disubstituted tetrahydrofurans, including the calyxolane natural products.
Article
Chemistry, Organic
Yunquan Man, Shiwen Liu, Bo Xu, Xiaojun Zeng
Summary: A method of N-fluorocarboxamide-directed N-heterocyclic-carbene (NHC)-catalyzed benzylic C-H acylation with aldehydes via the hydrogen atom transfer strategy is disclosed. This method involves a sequence of single-electron transfer, 1,5-hydrogen atom transfer, and radical cross-coupling steps, providing facile access to various highly functionalized ketones with good chemical yields and functional group tolerance.
Article
Chemistry, Multidisciplinary
Lingpu Meng, Jingjie Yang, Mei Duan, You Wang, Shaolin Zhu
Summary: Regio- and enantioselective hydroarylamination, hydroalkylamination and hydroamidation of styrenes have been developed using NiH catalysis with a simple bioxazoline ligand under mild conditions. A variety of enantioenriched benzylic arylamines, alkylamines and amides can be easily accessed by employing nitroarenes, hydroxylamines and dioxazolones as amination reagents. Chiral induction in these reactions is proposed to proceed through an enantiodifferentiating syn-hydronickellation step.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Alexander Yu. Rulev, Ilya N. Zubkov, Igor A. Ushakov, Valentin A. Semenov, Alexander V. Vashchenko, Jacques Maddaluno
Summary: The regioselectivity of the conjugate nucleophilic addition of amines to vicinal di-acceptor-substituted alkenes has been studied. Results obtained with standard primary and secondary amines provide clues on the relative acceptor character of electron-withdrawing groups (EWG), and the computed inverse local nucleophilicity index can predict the regioselectivity of the nucleophilic attack.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Hui-Yi Yang, Liang-Quan Lin, Na-Qi Li, Zhi-Hui Ren, Zheng-Hui Guan
Summary: In this study, we reported a novel palladium-catalyzed selective branched 3,4-hydroaminocarbonylation of 1,3-dienes to synthesize beta,gamma-unsaturated amides. This reaction utilizes readily available starting materials and tolerates a wide range of functional groups, providing an easy and effective approach to access diverse alpha-substituted beta,gamma-unsaturated amides. Mechanistic investigations suggest that the hydropalladation of dienes is irreversible and the insertion of CO into the allyl-Pd species is likely the rate-limiting step.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Linda E. Eijsink, Andy S. Sardjan, Esther G. Sinnema, Hugo den Besten, Keimpe J. van den Berg, Jitte Flapper, Rogier van Gemert, Ben L. Feringa, Wesley R. Browne
Summary: The curing process of bis-methacrylate-styrene resins was monitored using EPR and Raman spectroscopy. The results show the appearance and persistence of methacrylate and polystyrene radical species during the polymerization. Temperature and conversion rate also impact the radical signals.
Article
Chemistry, Physical
Jorn D. Steen, Anouk Volker, Daniel R. Duijnstee, Andy S. Sardjan, Wesley R. Browne
Summary: This study reveals that potential-induced changes in the SERS spectra of self-assembled monolayers of thiophenol on roughened gold surfaces can be attributed to local changes in pH at the electrode. The pH at the electrode can undergo significant changes during electrochemical measurements and takes considerable time to recover to the pH of the bulk solution.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Chaoyi Yao, Hongyu Lin, Brian Daly, Yikai Xu, Warispreet Singh, H. Q. Nimal Gunaratne, Wesley R. Browne, Steven E. J. Bell, Peter Nockemann, Meilan Huang, Paul Kavanagh, A. Prasanna de Silva
Summary: This article introduces a new method to control electron/proton transfers in water by capturing or releasing molecules. By using shape-switchable hosts and inclusive binding of metal complexes, reaction rates can be controlled and it has important applications in photocatalysis, electrocatalysis, and luminescent sensing.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Simon Krause, Jack D. Evans, Volodymyr Bon, Stefano Crespi, Wojciech Danowski, Wesley R. Browne, Sebastian Ehrling, Francesco Walenszus, Dirk Wallacher, Nico Grimm, Daniel M. Tobbens, Manfred S. Weiss, Stefan Kaskel, Ben L. Feringa
Summary: The study explores the application of photoswitches as light-responsive triggers for phase transitions of porous materials. By incorporating an azobenzene photoswitch in the backbone of a metal-organic framework, the researchers achieve light-induced structural contraction and gas adsorption control in the porous network. The complex mechanism of light-gated breathing is established, revealing a novel light-induced deformation mechanism of constrained azobenzene photoswitches.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Johann B. B. Kasper, Pattama Saisaha, Maurits de Roo, Mitchell J. J. Groen, Laia Vicens, Margarida Borrell, Johannes W. W. de Boer, Ronald Hage, Miquel Costas, Wesley R. R. Browne
Summary: This study elucidates the mechanism and reactive species involved in the oxidation of alkenes and alcohols with H2O2 under the presence of a specific catalyst. The findings suggest that a certain reactive species can engage in both alkene and alcohol oxidation reactions, exhibiting selectivity.
Review
Chemistry, Physical
Jorn D. Steen, Daniel R. Duijnstee, Wesley R. Browne
Summary: Molecular switching has become a key functionality in addressable materials and surfaces. However, the wide variation in interfaces studied, from single-molecule devices to two-dimensional self-assembled monolayers and thin films, poses challenges in their use and characterization. The low number density of molecules on modified interfaces and the complexity of characterizing molecular function further complicate the analysis. This review discusses the techniques and approaches used for characterizing molecular switches applied to interfaces and emphasizes the importance of understanding the limitations and quirks of specific techniques through the use of model compounds.
SURFACE SCIENCE REPORTS
(2023)
Article
Multidisciplinary Sciences
Palas Roy, Wesley R. Browne, Ben L. Feringa, Stephen R. Meech
Summary: Controlling molecular translation at the nanoscale is a key objective for development of synthetic molecular machines. Recently developed third generation photochemically driven molecular motors (3GMs) offer the possibility of converting light energy into translational motion. Detailed understanding of their excited state dynamics facilitates the development of 3GMs.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Johann B. Kasper, Laia Vicens, C. Maurits de Roo, Ronald Hage, Miquel Costas, Wesley R. Browne
Summary: Mononuclear MnII oxidation catalysts with aminopyridine-based ligands achieve high TON enantioselective epoxidation of alkenes with H2O2. The electronic effect of peripheral ligand substituents plays a role in the enantioselectivity and maximum TON. The use of low temperatures and slow addition of H2O2 reduces competing H2O2 disproportionation and improves TONs for alkene oxidation.
Article
Chemistry, Multidisciplinary
Palas Roy, Andy S. Sardjan, Wojciech Danowski, Wesley R. Browne, Ben L. Feringa, Stephen R. Meech
Summary: In this study, a novel push-pull overcrowded alkene motor was synthesized and characterized by steady-state and ultrafast time-resolved electronic spectroscopy. It was found that tuning the charge transfer character in the excited state has a significant effect on the photoisomerization yield, providing new routes for precise control of motor efficiency.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
W. J. Niels Klement, Jorn D. Steen, Wesley R. Browne
Summary: Electrochemistry and electrochemical reactions play a crucial role in the transition to a sustainable chemical industry. To understand these reactions, time-, potential-, and spatially resolved analysis is necessary. This study demonstrates the use of surface-enhanced Raman scattering (SERS) and resonance Raman spectroscopy for spatially and time-resolved analysis of solution composition at and near the electrode surface. The results show the potential of this approach in elucidating electro(catalytic) reactions at electrode interfaces. Rating: 7/10
Article
Chemistry, Multidisciplinary
Harmke S. Siebe, Andy S. Sardjan, Sarina C. Massmann, Jitte Flapper, Keimpe J. van den Berg, Niek N. H. M. Eisink, Arno P. M. Kentgens, Ben L. Feringa, Akshay Kumar, Wesley R. Browne
Summary: Renewable polysaccharide feedstocks are widely used in bio-based food packaging, coatings, and hydrogels. However, their physical properties often require chemical modification, such as oxidation using periodate, to achieve desired characteristics. In this study, gum arabic was found to undergo oxidation primarily in the rhamnose and arabinose subunits, while galacturonic acids were unaffected. The oxidation process resulted in the formation of substituted dioxanes instead of aldehydes, which has implications for crosslinking strategies in the development of renewable polysaccharide-based materials.
Article
Chemistry, Multidisciplinary
Cosima Staehler, Lars Grunenberg, Maxwell W. Terban, Wesley R. Browne, Daniel Doellerer, Michael Kathan, Martin Etter, Bettina Lotsch, Ben L. Feringa, Simon Krause
Summary: The incorporation of molecular machines into porous framework structures has the potential to enhance various functions such as nano actuation and molecular transport. In this study, a light-driven molecular motor was synthesized and integrated into polymers and covalent organic frameworks (COF). The structural and dynamic properties of the resulting solids were analyzed using spectroscopic, diffraction, and theoretical methods. A crystalline 2D COF with stacked hexagonal layers containing 20 mol% molecular motors was successfully synthesized. The COF exhibited high pore volume and surface area. The supramolecular assembly and motor dynamics of the COF layers were also investigated. This research provides important insights for the analysis, design, and synthesis of motorized porous framework materials.
Article
Chemistry, Multidisciplinary
Johan Bootsma, Wesley R. Browne, Jitte Flapper, Bas de Bruin
Summary: In this study, photoactive complexes were found to enable photochemical control over alkyd paint curing without the need for antiskinning agents. This approach provides greater flexibility in the curing process and outperforms commonly used cobalt- and manganese-based catalysts.
Article
Chemistry, Multidisciplinary
Nadja A. Simeth, Paula de Mendoza, Victor R. A. Dubach, Marc C. A. Stuart, Julien W. Smith, Tibor Kudernac, Wesley R. Browne, Ben L. Feringa
Summary: Molecular recognition-driven self-assembly using single-stranded DNA as a template is a promising method to obtain complex structures from simple building blocks. In this study, the beneficial properties of a photoresponsive biohybrid hydrogel were controlled with light, adding an extra level of function to the system. The structural response of the hydrogel at both the microscopic and macroscopic scale was studied, revealing remarkable shape-memory properties and shape manipulation capabilities.
Article
Materials Science, Multidisciplinary
Ruben Feringa, Harmke S. Siebe, W. J. Niels Klement, Jorn D. Steen, Wesley R. Browne
Summary: The study demonstrates that immobilizing photochromic molecular switches in a PMMA polymer matrix allows for tuning of color and transparency. By utilizing the primary inner filter effect and the layered construction of the films, only a single excitation wavelength is required for photochemical switching.
MATERIALS ADVANCES
(2022)
