Article
Chemistry, Physical
Koji Kubota, Daiyo Miura, Takumi Takeuchi, Shun Osaki, Hajime Ito
Summary: The study introduces a novel catalytic enantioselective nucleophilic borylation reaction of ketimines, leading to the efficient synthesis of optically active alpha-amino tertiary boronates with high enantioselectivity. The products can be further converted into peptidylboronic acid derivatives that are difficult to synthesize by other methods. Density functional theory calculations suggest that noncovalent interactions play a crucial role in determining the enantioselectivity of this reaction.
Article
Chemistry, Organic
Wen-Peng Yang, Shi-Kun Jia, Tian-Tian Liu, Yuan-Zhao Hua, Min-Can Wang
Summary: An efficient enantioselective [3 + 2] annulation of alpha-hydroxy-1-indanones and alkylidene azlactones has been developed with chiral dinuclear zinc catalysts via a Bronsted base and Lewis acid cooperative activation model, allowing for the synthesis of a broad range of chiral alpha-amino-gamma-butyrolactones with three stereocenters in good yields and excellent diastereo- and enatiostereoselectivities.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Multidisciplinary
Hu Tian, Hong-Ming Zhang, Liang Yin
Summary: In this article, a copper(I)-catalyzed asymmetric conjugate addition/protonation with selenols and alpha-substituted alpha,beta-unsaturated thioamides is described, which produces a series of chiral selenides with high to excellent enantioselectivity. The reaction shows a broad substrate scope for both selenols and alpha-substituted alpha,beta-unsaturated thioamides. The catalytic system is also successfully used for asymmetric selenation of beta-substituted alpha,beta-unsaturated thioamides. A [Cu-(R,R-P)-TANIAPHOS]-SePh species is identified by Se-77 NMR spectra, with a chemical shift at delta 462 ppm. Furthermore, a {[Cu-(R)-TOL-BINAP]-SePh}(2) species is characterized by X-ray analysis, confirming the formation of Cu-Se bond in the reaction. Finally, the straightforward transformations of the thioamide group to amine and thioester are demonstrated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Xiaolei Ji, Chaoren Shen, Xinxin Tian, Kaiwu Dong
Summary: A palladium-catalyzed asymmetric hydroesterification reaction was developed for preparing chiral alpha-substituted succinates with moderate yields and high ee values. The kinetic profile of the reaction progress indicated that the alkene substrate underwent hydroesterification followed by esterification with alcohol. The enantioselectivity was elucidated by density functional theory computation.
Article
Chemistry, Organic
Yu Qiao, Shiming Bai, Xiao-Feng Wu, Ying Yang, He Meng, Jialin Ming
Summary: This study discovered that the desymmetric arylation of prochiral cyclohexadienones with ArZnCl in the presence of an (R)-segphos-rhodium catalyst can yield cyclohexenones with a chiral arylated carbon center and a chiral all-carbon quaternary center with high selectivity. The catalytic system is also applicable to the arylation of spirocarbocyclic cyclohexadienones, producing cyclohexenones with a chiral spiro quaternary carbon.
Article
Multidisciplinary Sciences
Cheng Sheng, Zheng Ling, Yicong Luo, Wanbin Zhang
Summary: N,O-acetals are important building blocks for many synthetic intermediates, natural products, and pharmaceutical drugs. The authors developed a Cu-catalyzed asymmetric addition of alcohols to beta,gamma-alkynyl-alpha-imino esters, providing linear chiral N,O-ketals with high enantioselectivity.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Juanjuan Wu, Hongli Wu, Xinyu Liu, Yuekun Zhang, Genping Huang, Chun Zhang
Summary: A nickel-catalyzed reductive cross-coupling reaction has been developed for the synthesis of chiral α-CF3 ketones with high enantioselectivity and good functional group tolerance. The study of late-stage transformation demonstrated its applicability in preparing bioactive compounds. Control experiments further indicated the importance of the α-trifluoromethyl group in this reaction.
Article
Chemistry, Organic
Yixian Lou, Jian Qiu, Kai Yang, Feng Zhang, Chenglan Wang, Qiuling Song
Summary: The study presents a Ni-catalyzed reductive allylation of alpha-chloroboronates to efficiently produce homoallylic boronates, which can be easily converted into valuable homoallylic alcohols, amines, or 1,4-diboronates. This reaction demonstrates a broad substrate scope and good functional group compatibility, offering advantages over existing methods for the preparation of homoallylic boronates.
Article
Chemistry, Multidisciplinary
Xinpeng Cheng, Tianyou Li, Kaylaa Gutman, Liming Zhang
Summary: This study successfully synthesized alpha,beta-Butenolides with high enantiomeric excess using a novel Cu(I)-ligand cooperative catalysis, highlighting the importance of cooperation between the metal center and the ligand basic amino group. Moreover, it was found that other coinage metals such as Ag and Au can also play a similar role in this asymmetric isomerization chemistry.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Liang Tang, Yicong Luo, Cheng Sheng, Fang Xie, Wanbin Zhang
Summary: This article reports the efficient kinetic resolution of gamma-substituted alpha,beta-unsaturated gamma-lactams via a Cu-catalyzed asymmetric boron conjugate addition, which leads to the synthesis of chiral beta-hydroxy-gamma-lactams with beta,gamma-stereogenic carbon centers. The method is successful with a wide range of substrates and exhibits versatile transformations and synthetic utility in biologically active molecules. Mechanistic studies indicate that a Lewis acid Cu-I-catalyzed mechanism is the likely pathway in the catalytic reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Soshi Nishino, Yuji Nishii, Koji Hirano
Summary: A copper-catalyzed stereoselective 1,4-acylboration reaction between B(2)pin(2) and pivalic anhydride with a,b-unsaturated esters has been developed, yielding (E)-allylboronates with two distinct oxygenated functional groups at the gamma positions, a challenging transformation to achieve using other methods. The chemoselective post functionalizations of Bpin and pivalate moieties in the product are also demonstrated.
Article
Chemistry, Organic
Guangyang Xu, Zhen Wang, Ying Shao, Jiangtao Sun
Summary: An enantioselective copper-catalyzed tandem cross-coupling/alkynylogous aldol reaction has been developed, yielding tetrasubstituted allenoates with central and axial chirality. This protocol utilizes copper(II) salts as a catalytic precursor, distinguishing it from previous methods using Cu(I) salts.
Article
Chemistry, Organic
Ye Zhang, Jingcheng Guo, Jinna Han, Xiangui Zhou, Wei Cao, Zhenqian Fu
Summary: The bifunctional squaramide-catalyzed nucleophilic addition of thiophenols to easily available beta-silyl alpha,beta-unsaturated carbonyl compounds has been successfully developed, leading to the efficient preparation of a structurally diverse set of chiral alpha-mercaptosilanes with good to excellent yields and acceptable enantioselectivities. The reaction features mild reaction conditions, a broad substrate scope, and easy scale-up.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Jialin Qi, Fang Wei, Shuai Huang, Chen-Ho Tung, Zhenghu Xu
Summary: A new method has been developed for the synthesis of sulfur-containing chiral beta-lactams with two consecutive stereogenic centers using copper(I)-catalyzed asymmetric, three-component interrupted Kinugasa reaction. The key lies in the interception of in situ formed chiral four membered copper(I) enolate intermediate with sulfur electrophiles, resulting in good yields and excellent diastereo- and enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Georgia R. Harris, Aaron D. Trowbridge, Matthew J. Gaunt
Summary: We report the stereocontrolled addition of alpha-amino radicals to alkenes through visible-light-mediated photo-redox-catalysis, generating enantioenriched alpha-trialkyl-alpha- tertiary amines. This process utilizes a commercially available phenylglycinol derivative as a source of nitrogen and chiral information. DFT studies confirm the role of an intramolecular H-bond in rigidifying the transition state of the enantiodetermining step.
Article
Chemistry, Multidisciplinary
Koji Kubota, Tsubura Endo, Minami Uesugi, Yuta Hayashi, Hajime Ito
Summary: The study presents a palladium-catalyzed solid-state C-N cross-coupling of carbazoles with aryl halides via a high-temperature ball-milling technique, allowing for the efficient synthesis of N-arylcarbazole derivatives without the use of large amounts of organic solvents. Importantly, this method enables the coupling of poorly soluble aryl halides with large polyaromatic structures that are barely reactive under conventional solution-based conditions.
Article
Chemistry, Inorganic & Nuclear
Mingoo Jin, Rempei Ando, Hajime Ito
Summary: One-dimensional cationic coordination polymers can construct helical structures with different folding modes by diverse coordination geometries, leading to a change in emission wavelength in luminescent crystals.
INORGANIC CHEMISTRY
(2022)
Article
Public, Environmental & Occupational Health
Etsuji Suzuki, Michio Yamamoto, Eiji Yamamoto
Summary: This study discusses a new method for assessing confounding in a counterfactual framework, by examining the exchangeability of measures of association when exposure status is flipped in the population of interest. The results show that even if measures of association are exchangeable, confounding in distribution and in measure may still exist.
JOURNAL OF EPIDEMIOLOGY
(2023)
Article
Chemistry, Organic
Koji Kubota, Keisuke Kondo, Tamae Seo, Hajime Ito
Summary: This study investigates the unique reactivity of solid-state substrates and the effect of reaction temperature on the reaction rate. The results show that solid-state substrates with high melting points exhibit low reactivity, but the reaction rate can be accelerated by increasing the reaction temperature.
Article
Chemistry, Multidisciplinary
Yunpeng Gao, Chi Feng, Tamae Seo, Koji Kubota, Hajime Ito
Summary: The study demonstrates the efficient palladium-catalyzed Sonogashira coupling of solid aryl halides using high-temperature ball milling, resulting in a variety of materials-oriented polyaromatic alkynes and the synthesis of novel luminescent materials. The utility of this method is further exemplified by the rapid synthesis of a fluorescent metal-organic framework precursor, showcasing the potential of Sonogashira coupling for the preparation of functional materials.
Article
Chemistry, Physical
Mingoo Jin, Hajime Ito
Summary: This review summarizes the recent progress in stimuli-responsive mechanisms of Au(I) complexes, including crystal phase transitions and molecular rotation in crystalline media.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS
(2022)
Article
Chemistry, Physical
Yasutaka Kawai, Kazuki Haruguchi, Keisei Sumikawa, Mai Kawada, Eiji Yamamoto, Haruno Murayama, Makoto Tokunaga
Summary: In this study, the aerobic oxidation of isoprene glycol using Pt-Bi catalysts supported on ZrO2 or TiO2 was investigated. These catalysts showed high tolerance to high substrate concentration conditions and exhibited high recyclability.
APPLIED CATALYSIS A-GENERAL
(2022)
Article
Chemistry, Physical
Qi-An Huang, Takaaki Ikeda, Kazuki Haruguchi, Seiya Kawai, Eiji Yamamoto, Haruno Murayama, Tamao Ishida, Tetsuo Honma, Makoto Tokunaga
Summary: In this study, a Na-Au/ZrO2 catalyst was prepared and the role of sodium species in the reaction was studied. The active sites of the catalyst located on the surface of supported Au NPs were found to determine the reaction rate, and the rate-determining step was presumed to be protodeauration.
APPLIED CATALYSIS A-GENERAL
(2022)
Article
Chemistry, Applied
Qi-An Huang, Haruno Murayama, Eiji Yamamoto, Tetsuo Honma, Makoto Tokunaga
Summary: Metal oxides supported platinum catalysts with residual chloride are reusable soft Lewis acid catalysts for the isomerization of allylic esters. An investigation on the reusability and deactivation mechanism of supported platinum catalysts in the isomerization of but-3-ene-1,2-diyl diacetate was conducted. The reduction of PtOxCly species is the main reason for deactivation, and treating the used catalysts with HCl shows a great reactivation effect.
Review
Environmental Sciences
Toshihide Tsuda, Yumiko Miyano, Eiji Yamamoto
Summary: This passage describes a critical evaluation of a review paper that misused epidemiological methods. The review paper misinterpreted and compared the screening results of thyroid cancer after the Fukushima nuclear accident, while ignoring important information. The evaluation found that the paper misused epidemiological methods.
ENVIRONMENTAL HEALTH
(2022)
Article
Green & Sustainable Science & Technology
Taka-Aki Shinozaki, Masahiko Suenaga, Yohan Ko, Eiji Yamamoto, Haruno Murayama, Makoto Tokunaga
Summary: In this study, a UV light irradiation-based desulfurization method was developed for aromatic sulfur compounds without the use of catalysts or additives. The method was found to be efficient in removing sulfur from benzothiophene derivatives and dibenzothiophenes under room temperature and atmospheric pressure, producing sulfur allotropes.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Chemistry, Organic
Eiji Yamamoto, Kaoru Kobayashi, Kodai Wakafuji, Takashi Kamachi, Makoto Tokunaga
Summary: This study presents a detailed theoretical mechanistic investigation on the dynamic kinetic resolution of N-protected amino acid esters using phase-transfer catalysts. By applying the ConFinder program and the pseudo-TS conformational search (PTSCS) method, a semi-automatic exhaustive conformation search of transition state (TS)-like structures was conducted. The results of this conformational search method provided reasonable TS structures for determining the stereoselectivity in the asymmetric base hydrolysis of hexafluoroisopropyl (HFIP) esters as well as the racemization mechanism. Additionally, the independent gradient model (IGM) analysis of the TS structures revealed that H bonding interactions with the oxyanion hole and p-stacking interactions are common and important features in determining the stereoselectivity.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Kosuke Nakamoto, Junwen Bai, Minyan Zhao, Ryo Sakamoto, Liwei Zhao, Masato Ito, Shigeto Okada, Eiji Yamamoto, Haruno Murayama, Makoto Tokunaga
Summary: A metal-organic framework (MOF) with a redox active 1,4,5,8-naphthalenetetracarboxdiimide (NDI) derivative in its organic linker exhibits excellent rate performance as an electrode material for aqueous batteries due to its large pores. Among the tested aqueous electrolytes, K+-based ones demonstrate the highest rate performance, attributed to the highest mobility of the smallest hydrated K+ ion. However, the use of a counter electrode with insufficiently small pores offsets this advantage, suggesting that achieving maximum rate performance in aqueous batteries requires further development of electrode materials with sufficiently large pores.
Article
Mathematics, Interdisciplinary Applications
Etsuji Suzuki, Eiji Yamamoto
Summary: In this article, we discuss the concepts and calculation methods for various measures in the counterfactual framework, including the attributable fraction, preventable fraction, and prevented fraction. These measures are useful for assessing the impact of potential health interventions in exposed groups with causal or preventive effects. We also propose a new measure called the attributed fraction and discuss the relations between different measures and vaccine efficacy.
JOURNAL OF CAUSAL INFERENCE
(2023)
Article
Chemistry, Multidisciplinary
Chi Feng, Tomohiro Seki, Shunichi Sakamoto, Toshiyuki Sasaki, Satoshi Takamizawa, Hajime Ito
Summary: This study discovered a reversible multi-stage shape-changing effect in a molecular crystal, where the shape changes and luminescence-color changes were induced by multi-step thermal phase transitions. The findings provide new strategies for imparting additional functionalities to known shape-memory materials.
