Article
Chemistry, Multidisciplinary
Daven Foster, Pengchao Gao, Ziyun Zhang, Gellert Sipos, Alexandre N. Sobolev, Gareth Nealon, Laura Falivene, Luigi Cavallo, Reto Dorta
Summary: Chiral, cationic NHC-iridium complexes have been introduced as catalysts for the intramolecular hydroamination reaction of unactivated aminoalkenes, showing high activity and selectivity. By eliminating a major deactivation pathway, the efficiency of the reaction is improved. Through experimental and computational studies, valuable insights into the reaction mechanism have been gained.
Article
Chemistry, Multidisciplinary
Efrey A. Noten, Rory C. McAtee, Corey R. J. Stephenson
Summary: This research discloses an intramolecular reaction that utilizes a nitrogen radical to form a C-N bond and repurposes the nitrogen atom's activating group to form a C-C bond, enabling the efficient synthesis of arylethylamines. The protocol utilizes photoredox catalysis under mild conditions.
Review
Chemistry, Multidisciplinary
Rebecca C. DiPucchio, Sorin-Claudiu Rosca, Laurel L. Schafer
Summary: Hydroaminoalkylation is an efficient catalytic reaction for the reaction of amines with alkenes and alkynes. This reaction has potential applications in the pharmaceutical, agrochemical, and fine chemical industries, as well as in materials science. Different catalysts mediate hydroaminoalkylation through distinct mechanisms. Despite some barriers, further developments and applications of this reaction can be achieved by improving catalyst stability and reaction conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Pinaki Nad, Anil Kumar Behera, Anik Sen, Arup Mukherjee
Summary: In this study, a simple strategy for the N-alkylation of 2-aminopyridines with 1,2-diketones using BF3 center dot OEt2 as a catalyst was reported. The reaction proceeds under aerobic conditions, leading to the formation of a diverse range of substituted secondary amines in good to excellent yields. Mechanistic investigation using spectroscopic techniques and computational study revealed the formation of an iminium-keto intermediate with the liberation of CO2.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Madhawee K. Arachchi, Richard N. Schaugaard, H. Bernhard Schlegel, Hien M. Nguyen
Summary: Asymmetric reactions that convert racemic mixtures into enantioenriched amines, especially those with a tetrasubstituted carbon stereocenter, are of great importance in pharmaceutical research. In this study, a chiral diene-ligated rhodium-catalyzed asymmetric substitution reaction was developed to efficiently prepare α-trisubstituted-α-tertiary amines containing pharmaceutically relevant secondary amine cores.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Madhawee K. Arachchi, Richard N. Schaugaard, H. Bernhard Schlegel, Hien M. Nguyen
Summary: The asymmetric synthesis of α-trisubstituted-α-tertiary amines is of significant importance in the pharmaceutical industry. In this study, a chiral diene-ligated rhodium-catalyzed asymmetric substitution reaction was developed, leading to efficient synthesis with high yields and excellent selectivities.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Yong Guan, Tadas A. Buivydas, Remy F. Lalisse, Kalen B. Laybourn, Charlotte Stern, Margaret Richins, Sean M. Burns, Arielle Shelby, Christopher M. Hadad, Anita E. Mattson
Summary: The alkynylation of 4-siloxyquinolinium triflates was successfully achieved using copper bis-(oxazoline) catalysis. The optimal bis-(oxazoline) ligand was identified through computational analysis, resulting in dihydroquinoline products with up to 96% enantiomeric excess. Conversion of the dihydroquinoline products to biologically relevant and diverse targets was reported.
Article
Chemistry, Multidisciplinary
Nobuki Kishi, Yuki Adachi, Rui Jiang, Takahiro Doi, Da-Yang Zhou, Kaori Asano, Yasushi Obora, Takayoshi Suzuki, Hiroaki Sasai, Takeyuki Suzuki
Summary: The study describes the first successful example of a catalytic enantioselective intramolecular Tishchenko reaction, leading to the formation of chiral lactones in good yields with up to 91% ee. These enantioenriched lactones were then used for the first synthesis of (S)-cedarmycins A and B.
Article
Chemistry, Applied
R. Justin Grams, Monsurat M. Lawal, Connor Szwetkowski, Daniel Foster, Carol Ann Rosenblum, Carla Slebodnick, Valerie Vaissier Welborn, Webster L. Santos
Summary: A chemoselective, phosphine-catalyzed semireduction of primary and secondary propiolamides was reported, leading to the synthesis of acrylamides with excellent yield and (E)-stereoselectivity. The reaction tolerates various functional groups and DFT calculations revealed a clear energetic driving force for the (E)- over the (Z)-isomer.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Physical
Jere K. Mannisto, Ljiljana Pavlovic, Johannes Heikkinen, Tony Tiainen, Aleksi Sahari, Norbert M. Maier, Kari Rissanen, Martin Nieger, Kathrin H. Hopmann, Timo Repo
Summary: We developed a mildsuperbase-catalyzed carboxylation method for the synthesis of drug-like O-alkyl carbamates. Our mechanistic study reveals that when superbases interact with indoles and azoles, uncharged hydrogen-bonded complexes are formed instead of ionic salts. These complexes can be converted into carbamate salts upon exposure to CO2. The carbamate salts can be further classified into stable and fluxional types, with the latter being poor substrates for alkylation. We also identified the substrate-specific factors responsible for the fluxional behavior and proposed strategies to stabilize the carbamate salts for efficient alkylation.
Article
Chemistry, Multidisciplinary
Paritosh Mahato, Shashi Shekhar, Rahul Yadav, Saptarshi Mukherjee
Summary: This study comprehensively elucidates the role of the core and electrostatic surface of metal nanoclusters in catalytic reduction reactions. The electrostatic surface dramatically modulates the reactivity of metal nanoclusters.
Article
Chemistry, Multidisciplinary
Zeqian Du, Yongzhen Li, Yihan Liu, Ting Shi
Summary: This study elucidates the substrate recognition and catalytic process of the first bifunctional dehydratase-cyclase AmbDH3, which sheds light on the application of multifunctional DH domains in PKSs and benefits the chemoenzymatic synthesis of stereoselective pyran-containing products.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Soumyadip Patra, Ankit Kumar, Sanjay K. Singh
Summary: Efficient catalytic systems based on arene-Ru(II) complexes with bis-imidazole methane-based ligands were developed for additive-free hydrogen generation from formaldehyde and paraformaldehyde in water. The presence of bis-imidazole methane ligands significantly affected the catalytic performance of the studied catalysts. Among the screened complexes, a complex with the ligand [(eta(6)-p-cymene)RuCl(L)]Cl-+(-) ([Ru]-2) showed the highest turnover number (>20,000) for hydrogen gas generation from paraformaldehyde in water.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Tobias Koengeter, Can Qin, Binh Khanh Mai, Qinghe Liu, Yucheng Mu, Peng Liu, Amir H. Hoveyda
Summary: This paper presents a stereoretentive strategy for catalytic cross-metathesis reaction between tri-, Z- or E-di, or monosubstituted olefins and Z- or E-2-bromo-2-butene, leading to the formation of various trisubstituted alkenyl bromides. The method is applicable for the generation of products containing polar moieties or sterically hindered alkenes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Julien Braire, Aurelie Mace, Rania Zaier, Marie Cordier, Joelle Vidal, Claudia Lalli, Arnaud Martel, Francois Carreaux
Summary: An improvement in the catalytic enantioselective allylboration of isatins with 2-allyl-1,3,2-dioxaborolane in the presence of chiral BINOL derivatives is reported, offering an efficient one-step access to enantioenriched N-unprotected 3-allyl-3-hydroxy-2-oxindoles. The origins of the high enantioselectivity and the key role of the alcohol additive have been investigated.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Polymer Science
Kazushi Shibutani, Jun Nakai, Ketkanok Aphichartsuphapkhajorn, Yoshihito Kayaki, Shigeki Kuwata, Yoshihiko Arao, Masatoshi Kubouchi
Summary: The research demonstrates that oxygen and additional oxygen providers serve as activators for furfuryl alcohol polymerization, accelerating the construction of a conjugated structure and enhancing the mechanical properties of the cured resin.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Chemistry, Inorganic & Nuclear
Yohei Kashiwame, Takao Ikariya, Shigeki Kuwata
Summary: A series of iridium complexes with pyrazole ligands were synthesized and their reaction characteristics were explored under different reaction conditions, with their structures characterized.
Article
Polymer Science
Takuma Hanaoka, Yoshihiko Arao, Yoshihito Kayaki, Shigeki Kuwata, Masatoshi Kubouchi
Summary: Nitric acid decomposition is an effective method for recycling epoxy resin, with the chemical structure of the resin affecting the decomposition process; this study is the first systematic investigation into the relationship between chemical structure and decomposition.
POLYMER DEGRADATION AND STABILITY
(2021)
Article
Chemistry, Inorganic & Nuclear
Tatsuro Toda, Shigeki Kuwata
Summary: The synthesis and properties of polyprotic NNN pincer-type bis(pyrazole) iron complexes derived from a 1,3-bis(pyrazol-3-ylimino)isoindoline 1 were investigated. Various iron complexes were synthesized under different conditions, and the structures of the ligands were compared in details. The NH groups in the pincer ligand in the complexes showed their Bronsted acidic nature and some of the complexes exhibited catalytic activity for the disproportionation of hydrazine.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2021)
Article
Chemistry, Multidisciplinary
Takuma Hanaoka, Yoshihiko Arao, Yoshihito Kayaki, Shigeki Kuwata, Masatoshi Kubouchi
Summary: A new method for recycling decomposed amine-cured epoxy resin as a curing agent was developed in this study. The recycled resin exhibited higher tensile strength and comparable tensile modulus due to the presence of aromatic amino groups. By replacing a portion of the original curing agent, the optimized formulation of the recycled resin showed tensile strength comparable to that of the virgin resin.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Polymer Science
Atsuko Tabuchi, Teruaki Hayakawa, Shigeki Kuwata, Ryohei Ishige, Shinji Ando
Summary: By synthesizing N-cyclohexylphthalimide-substituted compounds, bright yellow fluorescence was observed in solution and crystalline states. Through substitution strategies, the resulting PI films displayed bright white fluorescence with a 1.7-fold increase in quantum yield.
Article
Materials Science, Multidisciplinary
Yoko Nambu, Yoko Yoshitake, Shohan Yanagi, Kenji Mineyama, Keisuke Tsurui, Shigeki Kuwata, Toshikazu Takata, Tadatomi Nishikubo, Ken Ishikawa
Summary: Dinaphtho[2,1-b:1 ',2 '-d]thiophene (DNT) is an organic high refractive index material with unique properties attributed to its flexible dynamic thiahelicene structure, allowing for metastable film-forming ability, high transparency, and high compatibility with PMMA. Chemical modification of DNT yields vinyl polymers with high refractive indices, demonstrating its potential as a promising candidate for organic polymeric high refractive index materials.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Naiqiang Liang, Shigeki Kuwata, Ryohei Ishige, Shinji Ando
Summary: A novel imide compound and polyimides with multiple intramolecular hydrogen bonds were synthesised to investigate the effects of distinct H-bond structures on photoluminescence properties, revealing excited-state intramolecular proton transfer as the main luminescence mechanism. These compounds show promise for solar spectral conversion applications.
MATERIALS CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Inorganic & Nuclear
Takuya Harada, Shinji Ando, Shigeki Kuwata
Summary: A ruthenium complex with an o-benzoquinone dioximate dianion was isolated, and the redox chemistry of its ligand was elucidated. The complex underwent ligand exchange and oxidation reactions, and the reduced ligand was regenerated through a catalytic reduction process with the aid of a base.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Correction
Chemistry, Multidisciplinary
Takuma Hanaoka, Yoshihiko Arao, Yoshihito Kayaki, Shigeki Kuwata, Masatoshi Kubouchi
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Chemistry, Organic
Takuma Kawada, Kenya Yabushita, Toshihisa Yasuda, Takeshi Ohta, Takaaki Yajima, Kouichi Tanaka, Noriyuki Utsumi, Masahito Watanabe, Kunihiko Murata, Yoshihito Kayaki, Shigeki Kuwata, Takeaki Katayama
Summary: Convenient asymmetric reductive amination of benzylic ketones was developed using newly designed Cp*Ir complexes as catalysts. The reaction produced a range of benzo-fused and acyclic ketones with high chemo- and diastereoselectivities, using readily available beta-amino alcohols as chiral aminating agents. The catalytic performance remained excellent even at a low catalyst dosage, and the reaction could be scaled up to over 100 g.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Hiroki Sato, Tadashi Tsukamoto, Hiromitsu Sogawa, Shigeki Kuwata, Toshikazu Takata
Summary: The study synthesized ruthenium complexes with a cavity-containing ligand and characterized their structures. Different types of pincer-type ligands were used during the synthesis, forming different complexes through thermal ligand exchange of CO with phosphorus ligands. The experimental results showed that these complexes exhibited catalytic activity and performed well in the hydrosilylation reaction.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Hiroki Sato, Tadashi Tsukamoto, Hiromitsu Sogawa, Shigeki Kuwata, Toshikazu Takata
Summary: Ruthenium complexes with pincer-type ligands were synthesized and characterized, and their structures and catalytic activities were studied.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Materials Science, Multidisciplinary
Atsuko Tabuchi, Teruaki Hayakawa, Shigeki Kuwata, Ryohei Ishige, Shinji Ando
Summary: A multi-colour solvatochromic fluorophore was developed, showing bright fluorescence in a full-colour range in different organic solvents and having potential applications in organic electronic devices and biological imaging tools.
MATERIALS ADVANCES
(2021)
Article
Chemistry, Inorganic & Nuclear
Satoshi Suzuki, Tatsuro Toda, Shigeki Kuwata
Summary: The creation of confined coordination spaces with controlled flexibility plays a crucial role in simulating enzymatic reactions. In this study, it was found that a simple non-chelating compound, 1,3-bis(diphenylphosphino)benzene (DPPBz), could assemble two Cp*Ru units to form a dinuclear complex. Treatment with excess hydrazine resulted in a diazene-bridged complex with intramolecular NH····Cl hydrogen bonds, while a monophosphine failed to stabilize this structure due to lack of conformational enforcement.
DALTON TRANSACTIONS
(2021)