Article
Chemistry, Physical
Nahiane Pipaon Fernandez, Gregory Gaube, Kyla J. Woelk, Mathias Burns, Damian P. Hruszkewycz, David C. Leitch
Summary: We present a new method for direct C-C bond formation using tandem C-O/C-H activation mediated by palladium catalyst. This approach allows for base-free direct C-H alkenylation by combining C-O oxidative addition at enol pivalates and concerted metalation-deprotonation of functionalized heterocycles. Mechanistic studies show that C-O oxidative addition is reversible and C-H activation occurs directly from the Pd(II) C-O oxidative addition product. In situ P-31 NMR spectroscopy reveals that (Cy3P)(2)Pd-(alkenyl)(OPiv) species is the predominant catalyst resting state during the reactions.
Article
Chemistry, Organic
Javeed Ahmad Tali, Ravi Shankar
Summary: Here, we report an unprecedented protocol using ruthenium-catalyzed annulation for the synthesis of 6H-chromeno[4 ',3 ':4,5]imidazo[1,2-a]pyridin-6-one, and a new method for intramolecular chelation-assisted C-H activation to produce functionalized 2-(3-formylimidazo[1,2-a]pyridin-2-yl)phenyl acetate. Furthermore, a one-pot approach using ruthenium catalysis and formic acid has been developed for the gram-scale synthesis of bis(2-phenylimidazo[1,2-a]pyridin-3yl)methane (BIP) and the late-stage functionalization of zolimidine, a marketed drug, with good yield.
Article
Chemistry, Organic
Yiu-Wai Yeung, Chun-Ming Chan, Yu-Ting Chen, Marco Chan, Mingyu Luo, Xin Gao, Bingnan Du, Wing-Yiu Yu
Summary: We have developed a Cu-catalyzed cross-electrophilic coupling reaction for the synthesis of alpha-amino acid derivatives using alpha diazoesters and O-benzoyl hydroxylamines. Cu(OAc)2 is used as the catalyst and polymethylhydrosilane (PMHS) as the hydride reagent. The reaction demonstrates excellent functional group compatibilities. The formation of a Cuacetoacetate complex was confirmed by ESI-MS analysis, and radical trap experiments suggest the involvement of nitrogen-centered radicals as intermediates. This strategy provides a simple and cost-effective approach for the synthesis of alpha-amino acid derivatives.
Article
Chemistry, Inorganic & Nuclear
Julien Petit, Anthony Cavaille, Nathalie Saffon-Merceron, Marie Fustier-Boutignon, Nicolas Mezailles
Summary: The reduction of a high spin paramagnetic complex by two electrons under N-2 resulted in the formation of two isomeric low spin diamagnetic complexes, which were successfully isolated and characterized. DFT calculations provided insights into the mechanism of double alpha,alpha CH bond insertion into a single sp(3) CH2 moiety. Fast exchange positions of hydrides in the cis dihydride complex were observed using NMR spectrocscopy.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Deborah Hartmann, Thaddaeus Thorwart, Rosa Mueller, Jean Thusek, Jan Schwabedissen, Andreas Mix, Jan-Hendrik Lamm, Beate Neumann, Norbert W. Mitzel, Lutz Greb
Summary: This study comprehensively investigates the structure of tetracoordinate bis(catecholato) silane through various experimental techniques. The compound shows unprecedented phase adaptation and reveals dynamic covalent features of the most abundant chemical bond in Earth's crust.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Feijing Chen, Wenjing Guo, Yan-Na Ma, Xuenian Chen
Summary: A highly efficient Pd-catalyzed B(9)-H/B(9)-H oxidative dehydrogenation coupling reaction for the synthesis of 9,9'-bis-o-carboranes has been developed. The properties and derivatization of 9,9'-bis-o-carborane were also investigated, resulting in diverse bis-o-carborane derivatives and bis-nido-carborane.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Jin Zhang, Xin Wang, Jiale Liu, Xiaogang Wang, Xinkan Yang, Qun Zhao, Yangmin Ma, Ran Fang, Michal Szostak
Summary: Here, we report a mild Ru(0)-catalyzed cleavage of C(aryl)-O bonds enabled by a combination of a Ru-3(CO)(12) catalyst and an imine auxiliary. This method offers rapid entry to synthetically valuable biaryl aldehydes from abundant anisoles. The synthetic utility of this strategy has been demonstrated in sequential processes to construct complex biaryls, exploiting the orthogonal selectivity of C-O bond activation.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Ke-Xin Wu, Yi-Ze Xu, Liang Cheng, Run-Shi Wu, Peng-Ze Liu, Da-Zhen Xu
Summary: This paper describes a method for directly constructing all-carbon quaternary centers from secondary C(sp(3))-H substrates through a dehydrogenative cross-coupling reaction, using FeCl2 center dot 4H(2)O as the catalyst and air as the terminal oxidant. This method provides 3,3-disubstituted oxindoles bearing all-carbon quaternary centers with excellent chemoselectivities under mild, ligand-free and base-free conditions.
Article
Chemistry, Multidisciplinary
Sehye Min, Jonghoon Choi, Changho Yoo, Peter M. Graham, Yunho Lee
Summary: This study demonstrates that a special nickel ion, supported by a rigid ligand, can activate C-H and C-O bonds at ambient conditions, playing a crucial role in synthetic applications.
Article
Chemistry, Organic
Sai Chen, Cong Lin, Yiqing Xu, Xiuhong Liu, Liang Shen
Summary: This study reports a new synthesis method for selectively aminating inert methyl and methylene gamma-C(sp(3))-O bonds of aliphatic amides with hydrazines, leading to the synthesis of gamma-hydrazine substituted carboxylic acid derivatives commonly found in drug molecules and other bioactive compounds.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Romain Melot, Marco Zuccarello, Diana Cavalli, Nadja Niggli, Michael Devereux, Thomas Burgi, Olivier Baudoin
Summary: This study showcases the unique reactivity profile of the IBiox ligand family in the Pd-0-catalyzed functionalization of nonactivated enantiotopic secondary C-H bonds, demonstrating high enantioselectivities for a broad range of valuable indane products. Analysis of the steric maps of the IBiox ligands provides insights into the correlation between enantioselectivity and spatial quadrants occupancy, offering a blueprint for designing more efficient ligands.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Yong Yuan, Liang-Sen Li, Lin Zhang, Feng Wang, Lin Jiang, Lin Zuo, Qi Wang, Jian-Guo Hu, Aiwen Lei
Summary: An electrochemical oxidative cross-coupling reaction has been developed, producing a series of unprecedented cross-coupling products under metal catalyst-, exogenous-oxidant-, and exogenous-electrolyte-free conditions. The resulting products are nearly insoluble in solvent, allowing for pure product isolation without silica gel column purification, and the prepared ammonium oxides are versatile building blocks for synthesizing pyrazole derivatives.
CHEMICAL COMMUNICATIONS
(2021)
Article
Biochemistry & Molecular Biology
Zhihao Niu, Qiaozhuo Wu, Qingzhong Li, Steve Scheiner
Summary: The tetrel bond between 1,2-benzisothiazol-3-one-2-TF3-1,1-dioxide (T = C, Si) and pyridine-1-oxide (PO) and its derivatives (PO-X, X = H, NO2, CN, F, CH3, OH, OCH3, NH2, and Li) was investigated using quantum chemical methods. The Si-O tetrel bond is strong, with interaction energies reaching a maximum of nearly 70 kcal/mol, while the C-O tetrel bond is weaker, with interaction energies between 2.0 and 2.6 kcal/mol. The presence of an electron-withdrawing substituent weakens the tetrel bond, while an electron-donating group strengthens it. The SiF3 group transfers approximately halfway between the acid's nitrogen and the base's oxygen without the assistance of cooperative effects from a third entity.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Kananat Naksomboon, Enrique Gomez-Bengoa, Jaya Mehara, Jana Roithova, Edwin Otten, M. Angeles Fernandez-Ibanez
Summary: Pd-catalyzed C-H functionalization reactions of non-directed substrates have emerged as a promising alternative to the use of directing groups. A new type of S,O-ligand has been found to be highly efficient in promoting Pd-catalyzed C-H olefination reactions of non-directed arenes, although its role in the process was unclear. Through various mechanistic tools, it was discovered that C-H activation is the rate-determining step and the S,O-ligand triggers the formation of more reactive Pd cationic species, explaining the observed acceleration of the reaction. These findings provide important insights into the role of the S,O-ligand in promoting Pd-catalyzed C-H functionalization reactions.
Article
Chemistry, Inorganic & Nuclear
Ryo Kobayashi, Shintaro Ishida, Takeaki Iwamoto
Summary: The isolable three-coordinate dialkylsilanone without substantial electronic stabilization reacts with ethers, cleaving the C-O or C-H and C-O bonds. The coordination of the ethereal oxygen atom to the Lewis acidic Si atom of the genuine Si=O bond is a key interaction for the reaction, as shown by the formation of Lewis base complexes and DFT calculations.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Kazuishi Fukuda, Nobuharu Iwasawa, Jun Takaya
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2019)
Article
Chemistry, Inorganic & Nuclear
Jun Takaya, Nobuharu Iwasawa
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2018)
Article
Chemistry, Multidisciplinary
Narumasa Saito, Jun Takaya, Nobuharu Iwasawa
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2019)
Article
Chemistry, Multidisciplinary
Kei Murata, Nobutsugu Numasawa, Katsuya Shimomaki, Jun Takaya, Nobuharu Iwasawa
FRONTIERS IN CHEMISTRY
(2019)
Article
Chemistry, Multidisciplinary
Ryosuke Yamada, Nobuharu Iwasawa, Jun Takaya
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2019)
Article
Chemistry, Multidisciplinary
Tatsuyoshi Ito, Nobuharu Iwasawa, Jun Takaya
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Takanobu Saitou, Yushu Jin, Kotaro Isobe, Takuya Suga, Jun Takaya, Nobuharu Iwasawa
CHEMISTRY-AN ASIAN JOURNAL
(2020)
Article
Chemistry, Physical
Jun Takaya, Koki Ogawa, Ryota Nakaya, Nobuharu Iwasawa
Article
Chemistry, Multidisciplinary
Kosuke Hirai, Yuki Homma, Tatsuyoshi Ito, Nobuharu Iwasawa, Jun Takaya
Summary: The photoreactivity of three-coordinate triarylboranes with a neighboring Lewis base moiety was investigated in this study. It was found that o-Anisyldimesitylborane underwent skeletal rearrangement under photoirradiation conditions, leading to the formation of (2-benzyl-4,6-dimethylphenyl)-mesitylborinic acid after hydrolysis. Experimental studies and theoretical calculations supported that the reaction proceeded via a triplet excited state and involved C-H abstraction and radical coupling to form a spiro boracycle intermediate. This study revealed the unique difference in photoreactivity of triarylboranes depending on the neighboring Lewis base moiety.
Review
Chemistry, Inorganic & Nuclear
Takashi Komuro, Yumiko Nakajima, Jun Takaya, Hisako Hashimoto
Summary: This review summarizes recent progress in the chemistry of transition metal complexes supported by multidentate chelate ligands, focusing on the incorporation of electropositive Group 13 and Group 14 elements as coordinating atoms. These electropositive element-based ligands offer unique functionalities and have applications in catalysis.
COORDINATION CHEMISTRY REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Kaito Kuroki, Tatsuyoshi Ito, Jun Takaya
Summary: By utilizing a photo-promoted skeletal rearrangement reaction, borabicyclo[3.2.0]heptadiene derivatives were successfully synthesized via boron-insertion into aromatic C-C bonds. The reverse reaction of dearomatized products was observed to occur in the dark at room temperature, achieving a photochemical and thermal interconversion between triarylboranes and boron-doped bicyclic systems.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Inorganic & Nuclear
Kazuishi Fukuda, Takuma Harada, Nobuharu Iwasawa, Jun Takaya
Summary: In this study, bis(o-phosphinophenyl)zinc derivatives were synthesized, and it was found that the presence of specific substituents significantly accelerated the transmetallation reaction between metals, resulting in the selective formation of diarylzinc.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Jun Takaya
Summary: Recent research has demonstrated the promising utility of transition metal complexes with M-E bonds stabilized by multidentate ligands, where E represents a main group metal or metalloid element. Main group metal and metalloid ligands provide unique electronic and steric environments to transition metals, leading to remarkable catalytic activity and product selectivity. This perspective highlights the potential of these compounds as a new class of supporting ligands for transition metal catalysts in synthetic chemistry.
Article
Chemistry, Multidisciplinary
Yuki Homma, Kazuishi Fukuda, Nobuharu Iwasawa, Jun Takaya
CHEMICAL COMMUNICATIONS
(2020)
Article
Chemistry, Inorganic & Nuclear
Jun Takaya, Mayuko Hoshino, Kanako Ueki, Narumasa Saito, Nobuharu Iwasawa
DALTON TRANSACTIONS
(2019)
