Review
Chemistry, Analytical
Ibukun Oluwaseun Shotonwa, Onome Ejeromedoghene, Adedoyin Oluseyi Adesoji, Yakubu Adekunle Alli, Caroline Akinremi, Sheriff Adewuyi
Summary: Iron-sulphur cofactors are important in biological redox reactions and mimicking them for hydrogen production has attracted global attention. Coordinatively saturated metal complex systems show remarkable activity for proton reduction compared to their unsaturated counterparts. The mechanisms of hydride formation in these systems can be investigated using experimental, spectroscopic, and computational techniques. This review highlights the connection between the electrochemistry and electrocatalysis of Fe-Fe-hydrogenase mimics and proposes future catalyst designs based on structure-catalytic activity relationships.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Ming-Sheng Xie, Ning Li, Yin Tian, Xiao-Xia Wu, Yun Deng, Gui-Rong Qu, Hai-Ming Guo
Summary: A study reported the use of bifunctional chiral PPY N-oxides as catalysts for dynamic kinetic resolution of racemic carboxylic esters, achieving high yields and enantioselectivity for the synthesis of chiral alpha-aryl alpha-alkyl carboxylic esters. Mechanistic studies revealed the crucial role of oxygen atoms in PPY N-oxides during the reaction process.
Article
Chemistry, Organic
Jungi Jung, Mugeon Song, Jun-Ho Choi, Won-jin Chung
Summary: This study investigated the factors influencing the enantioselectivity of the chiral Lewis base-catalyzed, SiCl4-promoted kinetic resolution of alpha,beta-dichloro cis-vinyl epoxide, and identified crucial factors determining stereocontrol in the process.
Article
Chemistry, Multidisciplinary
Shunichi Fukuzumi, Yong-Min Lee, Wonwoo Nam
Summary: This article focuses on deuterium kinetic isotope effects (KIEs) as criteria for elucidating redox mechanisms, including proton transfer, hydrogen transfer, and hydride transfer reactions. Different reaction pathways and mechanisms are discussed based on the redox properties of donors and acceptors, exhibiting unique KIEs. Temperature dependency of KIEs in aldehyde deformylation reactions distinguishes between two reaction pathways, shedding light on the mechanisms involved.
BULLETIN OF THE KOREAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Bin Wang, Yihang Li, Jia Hao Pang, Kohei Watanabe, Ryo Takita, Shunsuke Chiba
Summary: A protocol for regio-controlled hydromagnesiation of 1,3-enynes was developed using magnesium hydride generated in situ by solvothermal treatment of sodium hydride and magnesium iodide in THF. The resulting allenylmagnesium species could be converted into tri- and tetra-substituted allenes by subsequent treatment with various carbon- and silicon-based electrophiles with the aid of CuCN as a catalyst.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Fumihisa Kobayashi, Masashi Fujita, Takafumi Ide, Yuta Ito, Kenji Yamashita, Hiromichi Egami, Yoshitaka Hamashima
Summary: Thiobenzoic acid (TBA) can act as a single-electron reducing agent under blue light irradiation, enabling regioselective C alpha-H arylation of benzylamines, benzyl alcohols, ethers, and dihydroimidazoles through dual-role catalysis.
Article
Chemistry, Multidisciplinary
Ayako Watanabe, Kotaro Hama, Kohei Watanabe, Yuko Fujiwara, Kazuaki Yokoyama, Shigeo Murata, Ryo Takita
Summary: This study presents a protocol for the precise deuteration of straight-chain fatty acids, allowing for their persistent tracking and metabolic investigation. The research also identifies the acyltransferases involved in the metabolism of an oxidized fatty acid.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Takashi Mino, Toshiki Yamaoka, Kohei Watanabe, Chihiro Masuda, Shohei Kasano, Yasushi Yoshida, Ryo Takita, Yoshio Kasashima, Masami Sakamoto
Summary: P,olefin ligand/palladium catalyst systems can easily afford the corresponding 2-substituted 3-allylindole derivatives in good to excellent yields.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Kenji Yamashita, Yuki Fujiwara, Yoshitaka Hamashima
Summary: We describe an efficient method for benzylic C-H fluorination via sequential hydrogen-atom transfer (HAT) and oxidative radical-polar crossover utilizing the Ag(I)/Selectfluor system. Amide ligands, such as benzamide and sulfonamide, substantially facilitate the processes leading to a carbocation intermediate, which subsequently reacts with nucleophilic fluorinating reagent to form a C-F bond. This protocol is applicable to the fluorination of all 1 degrees, 2 degrees, and 3 degrees C-H bonds as well as to late-stage C-H fluorination of bioactive molecules.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Ryo Hirokawa, Yuki Nakahara, Shotaro Uchida, Kenji Yamashita, Yoshitaka Hamashima
Summary: We described regio- and enantioselective bromocyclization of difluoroalkenes catalyzed by chiral bisphosphine oxides. The reaction proceeds smoothly even at low temperature to provide bromodifluoromethyl-containing oxazolines with a chiral quaternary center in a highly enantioselective fashion. The protocol utilizes commercially available brominating reagents and readily accessible chiral catalysts, and the regioselectivity and enantioselectivity are influenced by the catalyst structure, the brominating reagent, and the reaction temperature. A gram-scale synthesis of chiral oxazoline was achieved with as little as 1 mol% of the catalyst.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Correction
Chemistry, Organic
Kenji Yamashita, Yuki Fujiwara, Yoshitaka Hamashima
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Kenji Yamashita, Yuji Tabata, Katsuya Yamakawa, Takuya Mochizuki, Kai Matsui, Manabu Hatano, Kazuaki Ishihara
Summary: Alkynyl addition to carbonyl compounds is an important synthetic method for the preparation of versatile chiral alcohols. In this study, a catalytic enantioselective addition of lithium acetylide to ketones using macrocyclic lithium binaphtholates as catalysts was reported. The designed macrocyclic structure prevented aggregation and resulted in monomeric and highly active catalysts that can produce enantioenriched tertiary alcohols from various ketones within a short reaction time.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Yoshiya Sekiguchi, Jia Hao Pang, Jia Sheng Ng, Jiahua Chen, Kohei Watanabe, Ryo Takita, Shunsuke Chiba
Summary: Solvothermal treatment of 1-naphthylmethylamine with KH or n-BuLi / t-BuOK in THF results in two consecutive beta-hydride eliminations, yielding 1-naphthonitrile and KH. The freshly generated KH can undergo dearomative hydride addition to the resulting 1-naphthonitrile at the C4 position, forming alpha-cyano benzylic carbanion, which can be further functionalized to obtain 1,4-dihydronaphthalene-1-carbonitriles with a quaternary carbon center.