Article
Chemistry, Multidisciplinary
Shiyao Liu, Yoshiaki Tanabe, Shogo Kuriyama, Ken Sakata, Yoshiaki Nishibayashi
Summary: In this study, propargylic substitution reactions using ruthenium and copper catalysis with N-monosubstituted hydrazones as ambident nucleophiles were investigated. It was found that N-monosubstituted hydrazones exhibited different reactivities depending on the catalytic system, resulting in either propargylic alkylated or aminated products. DFT calculations were used to study the reaction pathways and further transformation of the products yielded multisubstituted pyrazoles in good to high yields.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Editorial Material
Chemistry, Multidisciplinary
Shiyao Liu, Yoshiaki Tanabe, Shogo Kuriyama, Ken Sakata, Yoshiaki Nishibayashi
Summary: The cover of this issue features the research on the propargylic substitution reaction of propargylic alcohol with an N-monosubstituted hydrazone, where the nucleophilicity of the hydrazone is controlled by the choice of catalytic system. The full article can be accessed at 10.1002/chem.202103287.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Ken Sakata, Yui Goto, Takeshi Yoshikawa, Yoshiaki Nishibayashi
Summary: The enantioselectivity in propargylic substitution reactions catalyzed by optically active thiolate-bridged diruthenium complexes was investigated using DFT calculations. Transition-state structures leading to the major (R) product were found to be more abundant than those leading to the minor (S) product, suggesting a higher probability of forming the major product. The introduction of a phenyl group in the thiolate ligand was proposed to enhance selectivity, leading to a novel transition state model for the asymmetric catalytic reaction system.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
Article
Chemistry, Physical
Thiemo Arndt, Philip K. Wagner, Jonas J. Koenig, Martin Breugst
Summary: This study demonstrates that the Diels-Alder cycloaddition reaction can be efficiently conducted under mild and metal-free conditions using molecular iodine as the catalyst, leading to high endo selectivity in a short amount of time. Mechanistic studies revealed a halogen-bond activation mechanism and showed that iodine performs as well as typical metallic Lewis acids in this reaction.
Article
Chemistry, Multidisciplinary
Ridge Michael P. Ylagan, Eric Jaewon Lee, Daniela E. Negru, Paolo Ricci, Bohyun Park, Haram Ryu, Mu-Hyun Baik, P. Andrew Evans
Summary: We report an enantioselective rhodium(I)-catalyzed Pauson-Khand reaction using 1,6-chloroenynes that contain challenging 1,1-disubstituted olefins. Unlike previous studies, this new approach allows for a wider range of substrates, including both carbon and heteroatom tethers with polar and non-polar substituents on the alkene. DFT calculations reveal the critical role of the halide, which pre-polarizes the alkyne and provides the appropriate steric profile for a favorable interaction with the chiral diphosphine ligand.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Zhensheng You, Kosuke Higashida, Tomohiro Iwai, Masaya Sawamura
Summary: In this study, non-activated aryl fluorides were found to react with potassium diorganophosphinites through nucleophilic aromatic substitution to form tertiary phosphine oxides, with a mechanism involving nucleophile-dependent SNAr reaction pathways.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Ming-Xing Zhang, Lu Lin, Xiaofei Yang, Jun Yin, Jun Zhu, Sheng Hua Liu
Summary: A new class of complexes has been successfully synthesized and the reaction mechanism has been explored through experiments and DFT calculations. The substituents significantly affect the reaction rate, leading to the successful formation of the target complexes in the end.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Aleria Garcia-Roca, Raul Perez-Soto, Georgiana Stoica, Jordi Benet-Buchholz, Feliu Maseras, Arjan W. Kleij
Summary: Metal-catalyzed propargylic transformations are a powerful tool in organic synthesis for forming new carbon-carbon and carbon-heteroatom bonds. However, there is limited knowledge about the mechanistic intricacies of asymmetric propargylic reactions with challenging heteroatom substitution, presenting an inspiring challenge. This study presents a detailed mechanistic analysis of a propargylic sulfonylation reaction promoted by a chiral Cu catalyst through experimental techniques and computational studies. Surprisingly, the enantio-discriminating step was found to be the proto-demetalation step, rather than the coupling between the nucleophile and the propargylic precursor.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Raquel J. Rama, Celia Maya, Francisco Molina, Ainara Nova, M. Carmen Nicasio
Summary: 2-Aminobiphenyl palladacycles are successful precatalysts for Pd-catalyzed cross-coupling reactions. This study investigates the mechanism of aryl amination reactions catalyzed by a cationic 2-aminobiphenyl palladacycle supported by a terphenyl phosphine ligand. The results show that the formation of an aryl carbazolyl Pd(II) complex reduces catalyst decomposition and can be considered as an alternative precatalyst in cross-coupling reactions.
Article
Chemistry, Physical
Wei Wang, Yourong Tao, Xingcai Wu, Lijun Yang
Summary: This study proposes a unique three-dimensional Ru/CeO2 hybrid with interfacial effects to significantly enhance the performance of electrocatalysts for alkaline HER. The Ru/CeO2 interfaces as real active sites play a crucial role in optimizing the hydrogen binding and water absorption/dissociation energies. The optimal hybrid catalyst with low Ru loadings exhibits a small overpotential, low Tafel slope, and excellent long-term durability.
APPLIED SURFACE SCIENCE
(2022)
Article
Biochemistry & Molecular Biology
Marian Mikolajczyk, Marek Cypryk, Bartlomiej Gostynski, Jakub Kowalczewski
Summary: The mechanisms of three selected identity substitution reactions at phosphorus and sulfur have been investigated using density functional theory (DFT). The results show that these reactions can occur via stepwise or synchronous mechanisms, and DFT method is useful in distinguishing between these mechanisms.
Article
Biochemistry & Molecular Biology
Sebastian A. Cuesta, F. Javier Torres, Luis Rincon, Jose Luis Paz, Edgar A. Marquez, Jose R. Mora
Summary: In this study, the degradation mechanism of chloroacetanilide herbicides in the presence of four different nucleophiles was theoretically evaluated. The results showed that nucleophiles where a sulfur atom performs the nucleophilic attack are the most effective, and the R groups of the compounds have a negligible effect on the reaction process. Geometrical changes and electronic rearrangements were found to contribute significantly to the activation energy of the process.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Chemistry, Organic
Xiao-Hong Wang, Ya-Wen Xue, Chun-Yuan Bai, Yan-Bin Wang, Xiao-Hong Wei, Qiong Su
Summary: In this study, an effective and economical acid-promoted three-component reaction was developed for the synthesis of gamma-ketophosphine oxides, which involves the construction of C-P and C-C bonds with water as the only byproduct. Mechanistic experiments confirmed that the reaction proceeds through phospha-aldol elimination.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Multidisciplinary Sciences
Luo Ge, Esther G. Sinnema, Juana M. Perez, Roxana Postolache, Marta Castineira Reis, Syuzanna R. Harutyunyan
Summary: This study reports a general methodology for the selective synthesis of functionalized chiral Z-alkenes. The method utilizes readily available alkene-derived phosphines as an alternative to alkylating reagents in Wittig olefination, offering new retrosynthetic disconnections for the formation of functionalized disubstituted alkenes. The potential of this method is demonstrated by structural diversification of several bioactive molecules.
Article
Chemistry, Physical
Woo-Ok Jung, Binh Khanh Mai, Minjin Yoo, Samuel W. J. Shields, Jason R. Zbieg, Craig E. Stivala, Peng Liu, Michael J. Krische
Summary: The mechanism of pi-allyliridium C,O-benzoate-catalyzed allylic amination was studied using various methods. The reaction showed first-order dependence on catalysts and fractional-order dependence on amines. The intervention of cesium-bridged amine dimers and the formation of cesium amide nucleophiles were observed.
Article
Chemistry, Inorganic & Nuclear
Akira Yamamoto, Xueshi Liu, Kazuya Arashiba, Asuka Konomi, Hiromasa Tanaka, Kazunari Yoshizawa, Yoshiaki Nishibayashi, Hisao Yoshida
Summary: Selective reductive conversion of organic and inorganic compounds has been achieved using a combination of samarium(II) diiodide (SmI2) and water. In this study, we used in situ X-ray absorption spectroscopy to analyze the structure of the Sm2+-water complex in tetrahydrofuran (THF) in the presence of water. The results provide fundamental insights into the reactivity and chemoselectivity of the Sm2+-water complex system.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Takahiro Sawano, Masaki Ono, Ami Iwasa, Masaya Hayase, Juri Funatsuki, Ayumu Sugiyama, Eri Ishikawa, Takeshi Yoshikawa, Ken Sakata, Ryo Takeuchi
Summary: We report the branch-selective hydro-alkylation of simple alkenes using iridium catalysts. A variety of aliphatic and aromatic alkenes were suitable for this reaction, and the hydroalkylated products derived from malonic amides were suitable for further transformation. The reaction mechanism involves a reversible step followed by C-H reductive elimination.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Takeshi Yoshikawa, Yasuhiro Ikabata, Hiromi Nakai, Kentaro Ogawa, Ken Sakata
Summary: Conical intersections (CIs) play a crucial role in various photophysical, photochemical, and photobiological processes, but the systematic interpretation of minimum energy CI (MECI) geometries is unclear. A previous study investigated the MECI between the ground and first excited electronic states (S0/S1 MECI) using frozen orbital analysis (FZOA), identifying two controlling factors. However, one of the factors was found to be invalid for spin-flip TDDFT (SF-TDDFT). This study revisited the controlling factors using FZOA for the SF-TDDFT method and confirmed the control factors of S0/S1 MECI through numerical applications of a revised formula.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Multidisciplinary Sciences
Yulin Zhang, Yoshiaki Tanabe, Shogo Kuriyama, Ken Sakata, Yoshiaki Nishibayashi
Summary: Recently, transition metal-catalyzed enantioselective free radical substitution reactions have been recognized as convenient and important tools in synthetic chemistry. In this paper, we present a strategy to control enantioselective propargylic substitution reactions with alkyl radicals under photoredox conditions using a dual photoredox and diruthenium catalytic system. The successful example of transition metal-catalyzed enantioselective propargylic substitution reactions with free alkyl radicals is described.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Taichi Mitsumoto, Yuya Ashida, Kazuya Arashiba, Shogo Kuriyama, Akihito Egi, Hiromasa Tanaka, Kazunari Yoshizawa, Yoshiaki Nishibayashi
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Taichi Mitsumoto, Yuya Ashida, Kazuya Arashiba, Shogo Kuriyama, Akihito Egi, Hiromasa Tanaka, Kazunari Yoshizawa, Yoshiaki Nishibayashi
Summary: We have designed and synthesized a new molybdenum complex based on the bond dissociation free energies of N-H bonds in molybdenum-imide complexes with different substituted pyridine-based PNP-type pincer ligands. The complex exhibited excellent catalytic activity in the formation of ammonia from the reaction of dinitrogen with samarium diiodide and water under ambient conditions, with a significant improvement in catalytic performance compared to the unmodified complex.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Shun Suginome, Yoshiaki Nishibayashi
Summary: Organonitrogen compounds play a vital role in our lives, with ammonia serving as the primary nitrogen source. While ammonia is currently produced from dinitrogen and dihydrogen using the energy-intensive Haber-Bosch process, research into the direct synthesis of organonitrogen compounds from N2 using transition metal complexes is still in its early stages.
Article
Chemistry, Multidisciplinary
Jonathan Z. Z. Shezaf, Catherine G. G. Santana, Connor Saludares, Edward S. S. Briceno, Ken Sakata, Michael J. J. Krische
Summary: The first correlation between metal-centered stereogenicity and regio-selectivity in a catalytic process is described. Alternate pseudo-diastereomeric chiral-at-ruthenium complexes of the type RuX(CO)[& eta;(3)-prenyl][(S)-SEGPHOS] form in a halide-dependent manner and display divergent regio-selectivity in catalytic C-C couplings of isoprene to alcohol proelectrophiles via hydrogen autotransfer. Control of metal-centered diastereo-selectivity has unlocked the first catalytically enantio-selective isoprene-mediated carbonyl tert-prenylations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Manabu Hatano, Chiaki Nishioka, Ayaka Mimura, Risa Kimura, Yuki Okuda, Takeshi Yamada, Ken Sakata
Summary: This article describes a new type of catalyst that promotes a dehydrative esterification reaction between carboxylic acids and primary or secondary alcohols without the need to remove water. The reaction is conducted in toluene at 100 degrees C using a 2,2'-biphenol-derived phosphoric acid catalyst (2.5-10 mol%). The catalytic system is demonstrated to be useful for synthesizing pharmaceutically useful and acid-sensitive substrates.
Article
Chemistry, Multidisciplinary
Ken Sakata, Sarina Suzuki, Tsubasa Sugimoto, Takeshi Yoshikawa
Summary: The cycloaddition reaction between tropone and 1,1-diethoxyethene catalyzed by Lewis acid (LA) was studied using density functional theory (DFT) calculations. The presence of different Lewis acids (B(C6F5)3 or BPh3) led to different reaction pathways, favoring either [4 + 2] or [8 + 2] cycloaddition reactions, respectively. The nucleophilicity of the carbonyl O atom of tropone in the presence of LA was found to govern the selectivity of the reaction.
Article
Chemistry, Inorganic & Nuclear
Aya Eizawa, Kazuya Arashiba, Hiromasa Tanaka, Asuka Konomi, Kazunari Yoshizawa, Yoshiaki Nishibayashi
Summary: Dimolybdenum complexes bearing 3,3'''-(1,1':3',1'':3'',1'''-quaterphenylene)-bridged pyridine-based PNP-type pincer ligand were designed and prepared based on DFT calculations. These complexes serve as effective catalysts for the conversion of dinitrogen to ammonia under ambient reaction conditions, using samarium diiodide as a reductant and water as a proton source.
DALTON TRANSACTIONS
(2023)
