Article
Chemistry, Multidisciplinary
Alexandra Walter, Wolfgang Eisenreich, Golo Storch
Summary: This study reports a photochemical approach using flavin catalysts to oxidize silyl enol ethers to α,β-unsaturated ketones. The catalysts exhibit good stability throughout the reaction and can be successfully applied in subsequent aerobic epoxidation reactions. The sequential catalytic activity of flavin enables rapid diversification of substrates.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Rok Narobe, Kathiravan Murugesan, Simon Schmid, Burkhard Koenig
Summary: This study presents a metal-free system based on iodine (I/III) catalytic manifold that can generate carbenium ion intermediates at electronically disfavored positions. The system exhibits unusually high reactivity due to the complexation of iodine (III) intermediates with BF3. Detailed mechanistic investigations suggest two possible pathways for the decarboxylative Ritter-type amination protocol.
Review
Chemistry, Multidisciplinary
Johannes Grosskopf, Thorsten Bach
Summary: Upon irradiation with a suitable chiral catalyst, racemic compounds can be converted into enantiopure compounds through a process called photochemical deracemization. This review comprehensively covers the research and current developments in this field, discussing the reactions and mechanistic details underlying the presented reaction. Photochemical deracemization offers a unique opportunity to directly obtain enantiopure compounds from racemates, and short-lived intermediates play a key role in determining the enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Emir Al-Sayed, Sreejith P. Nandan, Elias Tanuhadi, Gerald Giester, Marco Arrigoni, Georg K. H. Madsen, Alexey Cherevan, Dominik Eder, Annette Rompel
Summary: In this study, three abundant-metal-based germanotungstate clusters were synthesized using a PO43- template. These clusters showed activity as molecular water oxidation catalysts, with Co-9 and Co-20 outperforming a well-known catalyst by a factor of 2. Among them, Co-9 currently represents the fastest Co-GT-based water oxidation catalyst, with a turnover frequency of 0.608 s(-1) and a turnover numbers (TONs) up to 159.9.
Article
Chemistry, Multidisciplinary
Yali He, Xiao Dan, Yurong Tang, Qian Yang, Wentao Wang, Yunfei Cai
Summary: An efficient and eco-friendly heterogeneous photocatalytic system has been developed using K-modified carbon nitride as a recyclable, nontoxic and heavy metal-free photocatalyst for fluoroalkylation-distal heteroaryl, formyl and imino migration reactions. This system utilizes air as the oxidant and RFSO2Na as the fluoroalkyl source, allowing for rapid and flexible construction of valuable fluoroalkyl functionalized compounds. The reaction process involves superoxide radicals, photogenerated electrons and holes playing important roles.
Review
Chemistry, Applied
Yudha P. Budiman, Stephen A. Westcott, Udo Radius, Todd B. Marder
Summary: Organoboron compounds are essential building blocks for organic reactions, with recent focus on the synthesis of fluorinated aryl boronic acid derivatives. However, instability issues arise under basic conditions, particularly accelerated in compounds with an ortho-fluorine group, leading to protodeboronation. Research is aimed at developing novel synthesis methodologies to avoid such issues.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Review
Chemistry, Multidisciplinary
Nadim Ayoub, Joumana Toufaily, Erwann Guenin, Gerald Enderlin
Summary: Lignocellulosic feedstocks can be used to generate biofuels and biochemicals, but methods using metal catalysts have some issues. This Review summarizes catalytic methods using metal and metal-free catalysts for oxidation reactions and demonstrates the potential of metal-free catalysts.
Article
Chemistry, Physical
Beata Gatlik, Wojciech Chaladaj
Summary: A Pd-catalyzed three-component protocol was developed for the direct synthesis of perfluoroalkyl-substituted alpha,beta-unsaturated esters using formates as convenient CO sources. The reaction proceeded smoothly under mild conditions with high yields and excellent selectivities. Detailed mechanistic studies supported by DFT calculations were conducted to understand the reaction pathway.
Article
Chemistry, Physical
Emmanuel D. Silva, Otavio A. L. Alves, Rogerio T. Ribeiro, Rafael C. R. Chagas, Jose A. F. P. Villar, Jefferson L. Princival
Summary: A new base-and halogen-free homogeneous oxidation system was developed in this study, aiming to selectively oxidize allyl, furyl, aryl, and heteroaryl primary alcohols. The system uses CuCl2/TMEDA/TEMPO with mild reaction conditions to produce aldehydes in high yields, and TMEDA as a ligand significantly affects the redox potential in the system.
APPLIED CATALYSIS A-GENERAL
(2021)
Review
Chemistry, Multidisciplinary
Juba Ghouilem, Morgane de Robichon, Franck Le Bideau, Angelique Ferry, Samir Messaoudi
Summary: Transition-metal-catalyzed C-H functionalization and photoredox nickel dual catalysis are innovative approaches for the synthesis of C-branched glycosides, providing efficient and mild methods for accessing a variety of complex C-branched glycosides of great interest.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Review
Chemistry, Physical
Karthick Muthuvel, Thirumanavelan Gandhi
Summary: The activation and functionalization of C-F bonds is a challenging task, but the use of NHC and metal-NHC enables easy access and reactivity for functionalization.
Article
Chemistry, Inorganic & Nuclear
Sebastian Amthor, Philip Keil, Djawed Nauroozi, Daniel Perleth, Sven Rau
Summary: A series of new Ruthenium(II) complexes based on a novel ligand were synthesized to evaluate the influence of phosphonate substitution on their catalytic performance. The introduction of phosphonate moiety did not alter the photophysical properties of the complexes, but affected their electrochemical features and photostability.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Zexian Li, Minyan Wang, Zhuangzhi Shi
Summary: An efficient method for photocatalytic perfluoroalkylation of vinyl-substituted all-carbon quaternary centers involving 1,2-aryl migration has been developed, generating valuable multisubstituted perfluoroalkylated compounds in a single step. Mechanistically, photoinduced alkyl radical addition to an alkene leads to migration of a vicinal aryl substituent from its adjacent all-carbon quaternary center, followed by generation of a C-radical bearing two electron-withdrawing groups and reduction by a hydrogen donor to complete the domino sequence.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Adam Pokluda, Zubair Anwar, Veronika Boguschova, Iwona Anusiewicz, Piotr Skurski, Marek Sikorski, Radek Cibulka
Summary: The study demonstrates that the ethylene-bridged 7,8-dimethoxyflavinium salt can effectively carry out photooxidation reactions, even with substrates of high oxidation potential. This salt is characterized by relatively long-lived excited state and high photostability.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Applied
Adam Pokluda, Zubair Anwar, Veronika Boguschova, Iwona Anusiewicz, Piotr Skurski, Marek Sikorski, Radek Cibulka
Summary: The study identified a superior photooxidation catalyst with high oxidation power and stability, suitable for oxidation reactions of various substrates, providing potential application prospects for further research.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Goki Hirata, Kentarou Takeuchi, Yusuke Shimoharai, Michinori Sumimoto, Hazuki Kaizawa, Toshiki Nokami, Takashi Koike, Manabu Abe, Eiji Shirakawa, Takashi Nishikata
Summary: This paper describes the reaction of tertiary alkyl alcohols and non-chiral or chiral alpha-bromocarboxamides as a source for the formation of congested ether compounds possessing two different tertiary alkyl groups.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Kentaro Mishiba, Yuya Tanaka, Munetaka Akita
Summary: This study reports the synthesis, electrochemical, and photophysical properties of aromatic hydrocarbons with dimesitylborylethynyl peripherals, showing effective π conjugation due to the spacer inserted between the bulky groups. Despite small structural differences, benzene, naphthalene, and anthracene derivatives exhibit different photophysical properties, with anthracene derivatives showing high quantum yields and aggregation-induced emission behavior. The anthracene derivatives also show unique absorption and emission bands derived from efficient intramolecular orbital interactions, resulting in materials with controllable HOMO-LUMO gaps.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Yuki Hyodo, Keigo Takahashi, Youhei Chitose, Manabu Abe, Michito Yoshizawa, Takashi Koike, Munetaka Akita
Summary: The host-guest assemblies of a designed compound and V-shaped aromatic amphiphiles proved to be effective photoredox catalysis systems with high reducing activity in water, particularly for the demethoxylative hydrogen transfer of Weinreb amides. This supramolecular strategy allows for easy tuning of visible-light photoredox catalysis in water.
Review
Chemistry, Multidisciplinary
Ranjini Laskar, Tanay Pal, Trisha Bhattacharya, Siddhartha Maiti, Munetaka Akita, Debabrata Maiti
Summary: Transition metal mediated C-H functionalization has been widely studied in organic synthesis, but the sustainability of these transformations is still underdeveloped. In this report, we explore metal-centered catalysis using mechanochemistry and microwave irradiation without toxic organic solvents. We discuss C-H functionalizations carried out in water and solvent-devoid conditions, as well as different metal centers and mechanistic pathways. This review aims to address environmental challenges and encourage innovative ideas for organic reactions.
Article
Chemistry, Multidisciplinary
Yuya Tanaka, Reo Kawano, Munetaka Akita
Summary: Controlling the localization/delocalization of radicals is crucial for functional materials. In this study, the authors synthesized and studied diruthenium (p-diethynylacene)diyl complexes and their monocationic radical species. They found that the energy gaps could be finely tuned by the acene rings in the bridging ligands, resulting in absorption maxima ranging from UV to NIR. The cationic species showed characteristic NIR bands attributed to charge resonance and pi-pi* transition bands, and the expansion of acene rings led to blue shifts of charge resonance bands and red shifts of pi-pi* transition bands.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Physical
Takashi Koike, Ryo Okumura, Tomoki Kato, Manabu Abe, Munetaka Akita
Summary: In this study, a method for photocatalytic generation of alkyl radicals from readily accessible alkyl benzoate esters is described. The excited organic photocatalyst, 1,4-bis(diphenylamino)benzene (BDB), acts as a one-electron injector. The hydroxy-1,1-dialkylfluoroethylation of aromatic alkenes is achieved using this photoredox-catalytic system. Furthermore, a strategy for generating fluoroalkyl radicals from readily available 2-fluorinated 1,1-dialkylethanols is developed.
Article
Chemistry, Multidisciplinary
Takashi Koike
Summary: This article introduces the easy-to-handle, solid, and bench-stable fluoroalkyl sulfoximines as electron-accepting fluoroalkyl radical sources, which can generate fluoroalkyl radicals using strong one-electron injectors. Our group has developed photocatalytic radical di- and mono-fluoromethylation and alpha-monofluoroalkylation of olefins using these sulfoximines. Appropriate combinations of fluoroalkyl sulfoximines and photoredox catalysts for successful radical fluoroalkylation have been discussed in this personal account.
Editorial Material
Chemistry, Organic
Munetaka Akita, Paola Ceroni, Corey R. J. Stephenson, Geiraldine Masson
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Yuya Tanaka, Yeana Bae, Fumiya Ogasawara, Keita Suzuki, Shuji Kobayashi, Satoshi Kaneko, Shintaro Fujii, Tomoaki Nishino, Munetaka Akita
Summary: Precise control of molecule-electrode interface is achieved by designing ruthenium acetylide molecular wires with long-legged phosphine ligands, allowing for sterically controlled molecule-electrode interface. The observation of sharpened Raman signals for acetylene stretching in the self-assembled monolayers suggests the formation of uniform SAMs due to steric hindrance. Scanning tunneling microscope break-junction study reveals narrow conductance features, indicating a uniform molecular junction and effective electronic interactions unique to the long-legged derivatives.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Organic
Takashi Koike
Summary: Small aromatic compounds with two diarylamino groups act as highly reducing organic photocatalysts (OPCs) by utilizing their excited state. The combination of an OPC and a fluoralkylating reagent is crucial for the success of radical fluoralkylation. This article discusses the design of the photocatalyst and the photocatalytic fluoroalkylation of olefins.
Article
Chemistry, Multidisciplinary
Yuya Tanaka, Hiroki Takahashi, Munetaka Akita
Summary: Understanding the electronic properties of mixed-valence states of organometallic molecular wires is crucial for studying electron transfer phenomena. In this study, diruthenium bridging wires with acyl-substituted cyclopentadienyl rings were synthesized and their properties were investigated. It was found that the interaction between the two metal centers is stronger in the para-isomers than in the meta-isomers. The spectroelectrochemical study showed significant higher-energy shifts of the (C O) vibrations upon oxidation, and the electron transfer rate constants were determined to be in the orders of 10(12) s-1 (para-isomers) and 10(9) s-1 (meta-isomers).
ACS ORGANIC & INORGANIC AU
(2022)
Article
Chemistry, Multidisciplinary
Shiori Ogawa, Swarup Chattopadhyay, Yuya Tanaka, Tatsuhiko Ohto, Tomofumi Tada, Hirokazu Tada, Shintaro Fujii, Tomoaki Nishino, Munetaka Akita
Summary: Control of charge carriers through molecular structure reveals the unique substituent effects on conduction orbitals, with drastic changes in conductance properties due to intrinsic narrow HOMO-LUMO gaps. The study investigates single-molecule conductance and dominant conductance routes, showing a shift from HOMO to LUMO conductance based on substituent groups. This research highlights the importance of terminal anchor groups in determining the charge carrier and conducting behavior in molecular junctions.
Review
Chemistry, Multidisciplinary
Takashi Koike, Munetaka Akita
Summary: The electron is unique and has the ability to participate in various systems, with novel electron injection methods revolutionizing chemical bond formation techniques in organic synthesis. In particular, visible-light organic photoredox catalysis has rapidly spread among synthetic chemists due to its sustainability and versatility.
TRENDS IN CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yuya Tanaka, Yuya Kato, Kaho Sugimoto, Reo Kawano, Tomofumi Tada, Shintaro Fujii, Manabu Kiguchi, Munetaka Akita
Summary: This study reports multinuclear organometallic molecular wires with high conductance attributed to efficient energy alignment between the Fermi level of the metal electrodes and the HOMO levels of the molecular wires. Strong Ru-Ru interaction through bridging ligands raises the HOMO levels to access the Fermi level, leading to high conductance and small attenuation factors.
Article
Chemistry, Multidisciplinary
Ryo Taniguchi, Naoki Noto, Seiya Tanaka, Keigo Takahashi, Sujan K. Sarkar, Ryoko Oyama, Manabu Abe, Takashi Koike, Munetaka Akita
Summary: A metal-free and operationally simple strategy has been developed for the generation of various alpha-monofluoroalkyl radicals, using a combination of 1,4-bis(diarylamino)naphthalene photocatalyst and sulfoximine-based fluoroalkylating reagents. This protocol can be applied to the modular synthesis of beta-monofluoroketones through radical monofluoroalkylation of alkenyl acetates.
CHEMICAL COMMUNICATIONS
(2021)
