Article
Chemistry, Physical
Aniket Mishra, Ping Wu, Xuefeng Cong, Masayoshi Nishiura, Gen Luo, Zhaomin Hou
Summary: In this study, we report the exo-selective, regiospecific annulation of a wide range of functionalized aromatic substrates with 1,1-disubstituted alkenes through C(sp(2))-H and benzylic C(sp(3))-H activation using half-sandwich rare-earth catalysts. This protocol provides a straightforward and atom-efficient route for synthesizing indane and tetralin derivatives bearing an all-carbon quaternary stereocenter that were previously difficult to access using other catalysts. The reaction mechanism has been elucidated through deuterium-labeling experiments and DFT calculations.
Article
Chemistry, Organic
Yuan-Xiang He, Kui Hu, Yu Ran, Zhen-Yao Lei, Shu Geng, Li-Na Chen, Li Pan, Jun-Bo Zhong, Feng Huang
Summary: This study presents a novel method for the one-pot construction of structurally new isoindolinone and isoquinolinone fused oxazinane compounds through intramolecular cascade cyclization using photogenerated N-amidyl radicals. The transformation proceeds smoothly under mild conditions, with low catalyst loading and good functional group tolerance, providing an efficient and concise approach for synthesizing valuable nitrogen-containing polyheterocycles.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Yuan-Xiang He, Kui Hu, Yu Ran, Zhen-Yao Lei, Shu Geng, Li-Na Chen, Li Pan, Jun-Bo Zhong, Feng Huang
Summary: A novel and practical method for synthesizing structurally valuable nitrogen-containing polyheterocycles has been developed in this study. The method proceeds smoothly under mild conditions with low catalyst loading and exhibits good functional group tolerance.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Dimitrije Djukanovic, Maximilian A. Ganiek, Kohei Nishi, Konstantin Karaghiosoff, Kazushi Mashima, Paul Knochel
Summary: A new convenient method for the preparation of dicarbamoylzincs is reported in this study. The target compounds were obtained by reacting ZnCl2 and formamides or TMP2Zn with formamides. This method is compatible with sensitive functional groups such as esters, ketones, or nitro groups. The reaction of these dicarbamoylzincs with various functionalized allylic, benzylic, aryl, alkenyl compounds, acid chlorides, aldehydes, or enones resulted in the synthesis of polyfunctional amides in high yields. The C-13 NMR characterization of these new compounds is presented.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Daiki Kato, Tomoya Murase, Jalindar Talode, Haruki Nagae, Hayato Tsurugi, Masahiko Seki, Kazushi Mashima
Summary: This study demonstrates the selective synthesis of multifunctionalized ketones using copper salts and aryl Grignard reagents. The method shows good tolerance towards various functional groups and can be applied to the synthesis of important synthetic intermediates.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Darryl F. Nater, Christoph J. Kaul, Lukas Laetsch, Hayato Tsurugi, Kazushi Mashima, Christophe Coperet
Summary: Tailored molybdenum (VI)-oxo complexes can catalyze olefin metathesis reaction under specific conditions, and the structural, spectroscopic and electronic characteristics of the catalyst precursor have an influence on the initiation and catalytic efficiency of the final product.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Physical
Koichi Shinohara, Hayato Tsurugi, Kazushi Mashima
Summary: In this study, a novel lanthanum amide complex was reported as an efficient catalyst for the N-methylation of N-alkylaniline derivatives with CO2 in the presence of PhSiH3. Experimental and computational investigations revealed the crucial role of multiple noncovalent interactions in the reaction mechanism.
Article
Polymer Science
Haruki Nagae, Shin-ya Akebi, Saki Matsushiro, Kazutaka Sakamoto, Takanori Iwasaki, Kyoko Nozaki, Kazushi Mashima
Summary: Active methylene compounds, such as nitrile compounds and carbonyl compounds, can act as chain transfer agents in the alternating copolymerization of CO2 and cyclohexene oxide to produce end-functionalized polycarbonates with narrow molecular weight distribution and high carbonate linkage. Acidic nitrile compounds can also result in double chain propagation to form telechelic polycarbonate diols.
Article
Chemistry, Multidisciplinary
Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
Summary: Chromium-catalyzed olefination of aryl aldehydes with haloforms using 2,3,5,6-tetramethyl-N,N'-bis(trimethylsilyl)-1,4-dihydropyrazine (1a) as an organic reducing agent leads to trans-selective formation of beta-halostyrene derivatives. This reaction eliminates the need for metal powders such as zinc and manganese as reductants, reducing metal-based reaction waste.
CHEMICAL COMMUNICATIONS
(2023)
Review
Chemistry, Inorganic & Nuclear
Mariko Inoue, Hayato Tsurugi, Kazushi Mashima
Summary: Transition metal catalyzed direct C-H activation offers a direct and atom-economical method for constructing new C-C bonds. This review focuses on the unique reactivity of early transition metal complexes towards C-H bonds in heteroatom-containing organic compounds, including pyridine derivatives and alkylamines.
COORDINATION CHEMISTRY REVIEWS
(2022)
Article
Engineering, Chemical
Taito Kato, Haruki Nagae, Koji Yonehara, Tomoyuki Kitano, Hiroki Nagashima, Shinji Tanaka, Tomoharu Oku, Kazushi Mashima
Summary: This paper discusses the development of anchoring homogeneous Zn or Zr complexes for catalytic transesterification reactions, focusing on the generation of monoesters from acrylates and diols. The immobilized catalysts in a flow reaction system are able to continuously produce monoesterified products without compromising catalytic activities under optimized conditions.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Chemistry, Inorganic & Nuclear
Tomomi Kawakami, Sota Tamaki, Satoru Shirase, Hayat o Tsurugi, Kazushi Mashima
Summary: A hexanuclear Ce(IV) cluster bridged by oxo and hydroxo groups was synthesized and found to exhibit strong absorption in the ultraviolet A to blue light region. Irradiation with blue LED light induced a chemical reaction, resulting in the formation of a new compound. This study is of great significance for understanding the properties and potential applications of this cluster.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Yohei Ueda, Hayato Tsurugi, Kazushi Mashima
Summary: Cobalt-catalyzed hydroalkynylation of alkynes, alkenes, and imines allows for the synthesis of internal alkynes with various functional groups adjacent to the carbon-carbon triple bond in an atom-economical manner. In addition, cross-coupling reactions using alkynylcobalt species generated in situ from terminal alkynes, haloalkynes, and metal acetylides selectively provide internal aryl and alkylalkynes.
Article
Chemistry, Physical
Kosuke Higashida, Valentin Smail, Haruki Nagae, Jean-Francois Carpentier, Kazushi Mashima
Summary: We successfully achieved nickel(0)-catalyzed asymmetric allylic alkylation (AAA) of beta-dicarbonyl compounds under ambient conditions by activating unstrained C-C bonds of 2-allylated 2-methylcyclohexane-1,3-dione derivatives. The reaction produced quaternary chiral compounds with high yield and enantioselectivity. The mechanism of the AAA reaction with the Ni(0)-(S)-tol-MeO-BIPHEP catalyst system was elucidated through control experiments and DFT calculations.
Article
Chemistry, Physical
Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
Summary: Chromium(III) trichloride combined with aryl/alkyl Grignard reagents showed high catalytic activity for the synthesis of syn-2-aryl/alkyl-1,2-dihydronaphthalen-1-ols through the ring-opening aryl/alkylation of 7-oxabenzonorbornadiene derivatives. The chromium catalyst allowed the use of unstable aryl Grignard reagents with esters and N-protecting groups. In situ formed diarylchromate(I) from tetraarylchromate(III) was identified as the active species in this catalytic reaction based on control experiments.
Article
Chemistry, Multidisciplinary
Haruki Nagae, Saki Matsushiro, Jun Okuda, Kazushi Mashima
Summary: We discovered that a cationic hetero tetranuclear complex with a calcium and three cobalt ions demonstrated high catalytic activity for the alternating copolymerization of propylene oxide (PO) and carbon dioxide (CO2). The tertiary anilinium salt [PhNMe2H][B(C6F5)(4)] was identified as the best additive to generate the cationic species and maintain polymer selectivity and carbonate linkage, even at 1.0 MPa CO2. Density functional theory calculations revealed that the reaction pathway mediated by the cationic complex is more favorable than that mediated by the neutral complex, with an energy difference of 1.0 kcal mol(-1). Additionally, we found that the exchange of flexible ligands between calcium and cobalt ions is crucial for the smooth proceeding of the alternating copolymerization.
Article
Chemistry, Physical
Kohei Nishi, Hayato Tsurugi, Kazushi Mashima
Summary: Chromium(III) trichloride in combination with aryl/alkyl Grignard reagents exhibited high catalytic activity for the ring-opening arylation reaction of 7-oxabenzonorbornadiene derivatives, producing syn-2-aryl/alkyl-1,2-dihydronaphthalen-1-ols in high yields. The superior catalytic activity of the chromium catalyst allowed the use of unstable aryl Grignard reagents. Control experiments suggested that the in situ formed diarylchromate(I) served as the active species in the catalytic reaction.
Article
Chemistry, Physical
Kosuke Higashida, Valentin Smail, Haruki Nagae, Jean-Francois Carpentier, Kazushi Mashima
Summary: We achieved a nickel(0)-catalyzed asymmetric allylic alkylation reaction of beta-dicarbonyl compounds under ambient conditions, resulting in high yields of quaternary chiral compounds with high enantioselectivity.
