Article
Chemistry, Physical
Tatsuya Kuremoto, Ren Sadatsune, Tomohiro Yasukawa, Shu Kobayashi
Summary: A novel core/shell structure support was designed to enhance the accessibility of reaction sites, showing higher catalytic activity in asymmetric 1,4-addition reactions. This design strategy may offer a general approach for obtaining other heterogeneous catalysts with high activities.
Article
Chemistry, Multidisciplinary
Yuki Saito, Shu Kobayashi
Summary: The application of heterogeneous catalysts in continuous-flow enantioselective hydroacylation reactions was studied. Catalysts were prepared by mixing supports and rhodium complexes, and showed excellent activity and enantioselectivity. Under optimized conditions, the catalysts exhibited high turnover numbers and could be applied to various substrates. Furthermore, sequential-flow reactions with other heterogeneous catalysts were demonstrated for the synthesis of biologically active molecules and functional materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Max Deimling, Shravan R. Kousik, Karina Abitaev, Wolfgang Frey, Thomas Sottmann, Kaloian Koynov, Sabine Laschat, Petia Atanasova
Summary: The study used macro-mesoporous silica inverse opal films as a model system to investigate the molecular infiltration behavior of a probe molecule. The results showed homogeneous tracer distribution in the SiO2-IO films and attachment to both transport and mesopores.
Article
Chemistry, Physical
Junwen Wang, Jun Li, Yan Wang, Sisi He, Hengzhi You, Fen -Er Chen
Summary: In this study, a polymer-supported chiral heterogeneous copper catalyst was reported, which demonstrated high reactivity and enantioselectivity in asymmetric conjugate addition reactions.
Article
Chemistry, Multidisciplinary
Manuel Kirchhof, Karina Abitaev, Abdulwahab Abouhaileh, Katrin Gugeler, Wolfgang Frey, Anna Zens, Johannes Kastner, Thomas Sottmann, Sabine Laschat
Summary: In Rh-catalyzed reactions using microemulsions, the chiral complex Rh(OAc) showed the greatest dependence on the composition of the microemulsion, indicating that the microenvironment significantly influences its catalytic activity and selectivity.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Yuki Saito, Shu Kobayashi
Summary: The article discusses the application of chiral heterogeneous Sc catalysts in continuous-flow reactions, achieving efficient synthesis of compounds through noncovalent interactions and the crucial role of heteropoly acid.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Yiqi Ren, Maodi Wang, Qihua Yang, Junfa Zhu
Summary: The development of chiral solid catalysts using unconventional strategies is crucial for efficient heterogeneous asymmetric catalysis. The study presents a chiral solid catalyst, chiral diamine modified Ni/SiO2, for asymmetric Michael addition. The experimental results demonstrate that the peripheral Ni sites in close contact with SiO2 support are likely to be the active sites.
Article
Chemistry, Physical
Qihua Yang, Junfa Zhu, Yiqi Ren, Maodi Wang
Summary: In this study, a chiral solid catalyst, chiral diamine modified Ni/SiO2, was prepared for asymmetric Michael addition. The experimental results showed that the chiral diamine modified Ni/SiO2 achieved a higher ee value and turnover frequency compared to chiral Ni complexes. The peripheral Ni sites in close contact with SiO2 support were identified as the active sites, distinct from homogeneous complexes. Continuous flow production of chiral compounds for more than 65 hours was achieved using the solid catalysts in a fixed bed reactor.
Article
Engineering, Environmental
Yanfei Zhang, Haonan Zhang, Jinxin Liu, Minli Tao, Ning Ma, Wenqin Zhang
Summary: A new fiber-based asymmetric catalyst PANQNF, formed by the combination of polyacrylonitrile fiber and quinine, exhibits advantages such as easy preparation, high activity, high enantioselectivity, wide reaction temperature range, simple separation, and good recyclability. It shows great potential for industrial application.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Applied
Kenya Tamaribuchi, Jiaqi Tian, Kengo Akagawa, Kazuaki Kudo
Summary: Enantioselective Michael addition of beta-dicarbonyl compounds towards nitroalkenes was achieved using an immobilized, N-terminal-guanidinylated peptide catalyst. Various nucleophiles and electrophiles were employed, with the resin-supported catalyst being recyclable for five cycles. This method shows promise for industrial applications.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Fei Li, Jing-Lan Kan, Bing-Jian Yao, Yu-Bin Dong
Summary: A general and efficient organocatalytic asymmetric polymerization approach has been developed for the synthesis of chiral covalent organic frameworks (CCOFs). Using a chiral 2-methylpyrrolidine catalyst, a series of chiral beta-ketoenamine-CCOFs were directly constructed from prochiral aldehyde- and primary amine-monomers. The obtained CCOFs can be further metalated and used as highly efficient catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Cuiping Yu, Weilong Wu, Min Gao, Yu Liu
Summary: This study reports the synthesis and characterization of modified cellulose-supported Rh catalyst. DAC-BINAP-Rh showed excellent catalytic performance in asymmetric hydrogenation and could be easily recycled. This work provides a novel supported catalyst for the application of cellulose in asymmetric catalysis.
Article
Chemistry, Physical
Vidmantas Bieliunas, Sigitas Stoncius
Summary: The design and synthesis of second generation C-2-symmetric ligands with additional substituents was reported. These substituents provide a further element for fine-tuning the ligand structure by enforcing conformational rigidity. The tetrasubstituted bicyclo[3.3.1]nona-2,6-dienes were successfully employed in the rhodium-catalyzed arylation reaction with good to excellent yields and enantioselectivities up to 99% ee.
Article
Chemistry, Physical
Chonglong Li, Murong Zhan, Zixuan Wang, Hua Gao, Yu Yang, Hongqian Gou
Summary: A novel helical poly(phenylisocyanide)-supported catalyst was synthesized with pendant (1R,2R)-1,2-cyclohexanediamine. The chiral cyclohexanediamine polymer catalyst exhibited excellent catalytic activity and stereoselectivity in the Michael addition reaction. The polymer poly-2(200) catalyzed the Michael addition reaction of cyclohexanone with trans-nitrosostyrene in the presence of benzoic acid, achieving high enantiomeric excess (ee) value up to 97% and diastereoselectivity (dr) value of 79/21. Furthermore, the chiral polymer catalyst showed recyclability for 3 times without significant loss of catalytic activity and could also catalyze the Aldol reaction of p-nitrobenzaldehyde with cyclohexanone with ee value of 49% and dr value of 60/40.
Article
Chemistry, Applied
Raja K. K. Rit, Hongyi Li, Stephen P. P. Argent, Katherine M. M. Wheelhouse, Simon Woodward, Hon Wai Lam
Summary: Chiral dienes are important ligands in asymmetric catalysis but they are difficult to obtain. In this study, a simple chiral allenecarboxanilide was used to produce pseudoenantiomeric bicyclo[2.2.2]octa-2,5-dienes containing an alkenyl bromide via intramolecular [4+2] cycloaddition. These compounds can be easily functionalized to provide diverse chiral diene ligands. The synthesis is straightforward and can be conducted on a large scale. The resulting ligands exhibit high performance in nine types of enantioselective Rh(I)-catalyzed addition reactions.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Organic
Tomohiro Yasukawa, Xi Yang, Shu Kobayashi
JOURNAL OF ORGANIC CHEMISTRY
(2020)
Article
Chemistry, Organic
Tomohiro Yasukawa, Zhiyuan Zhu, Yasuhiro Yamashita, Shu Kobayashi
Summary: A ligand-free approach using polysilane/alumina-supported palladium nanoparticles has been developed for carbonylative Suzuki-Miyaura coupling reactions to synthesize diaryl ketones. This method shows high yields and selectivities even with low catalyst loading under atmospheric pressure of CO gas. The immobilized palladium nanoparticles can be easily recovered by filtration and maintain catalytic activity for several runs.
Review
Chemistry, Multidisciplinary
Tomohiro Yasukawa, Hiroyuki Miyamura, Shu Kobayashi
ACCOUNTS OF CHEMICAL RESEARCH
(2020)
Article
Chemistry, Multidisciplinary
Xi Yang, Tomohiro Yasukawa, Tei Maki, Yasuhiro Yamashita, Shu Kobayashi
Summary: In this study, heterogeneous trifluoromethanesulfonic acid immobilized nitrogen-doped carbon-incarcerated titanium nanoparticle (NP) catalysts were developed, showing high activity for Friedel-Crafts acylation with low titanium loading. The addition of metals further changed the nature of the acidic species and enhanced catalytic activity, providing a promising approach for organic transformations.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Ryusuke Masuda, Tomohiro Yasukawa, Yasuhiro Yamashita, Shu Kobayashi
Summary: The development of a stable heterogeneous catalyst system using Rh nanoparticle catalysts supported on nitrogen-doped carbon has allowed for successful asymmetric catalysis reactions, achieving high yields and enantioselectivities of chiral alpha-amino acid derivatives. Nitrogen dopants played a crucial role in both catalytic activity and enantioselectivity, with the catalyst showing reusability in seven runs and efficiency in a continuous-flow reaction for over 90 hours.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Applied
Tatsuya Kuremoto, Ren Sadatsune, Tomohiro Yasukawa, Yasuhiro Yamashita, Shu Kobayashi
Summary: In this study, a ligand library containing 31 chiral diamines was synthesized and evaluated in a continuous-flow asymmetric 1,4-addition reaction. A prediction model for enantioselectivities was successfully constructed based on experimental results and virtual screening was conducted to identify promising structures with good enantioselectivities in experiments.
ADVANCED SYNTHESIS & CATALYSIS
(2021)
Editorial Material
Chemistry, Multidisciplinary
Tomohiro Yasukawa, Shu Kobayashi
ACS CENTRAL SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Tomohiro Yasukawa, Sanshiro Kume, Yasuhiro Yamashita, Shu Kobayashi
Summary: Nitrogen-doped carbon-supported Co/Cu bimetallic catalysts were found to efficiently catalyze the olefination of various aromatic aldehydes into unsaturated esters in the presence of triaryl phosphine, allowing for the recovery and reuse of the catalyst without significant loss of activity over multiple runs.
Article
Chemistry, Organic
Xi Yang, Tomohiro Yasukawa, Yasuhiro Yamashita, Shu Kobayashi
Summary: Heterogeneous catalysts immobilized with trifluoromethanesulfonic acid on nitrogen-doped carbon-incarcerated niobia nanoparticles (NCI-Nb-TfOH) have been developed, showing excellent catalytic performance with low niobium loading (1 mol %) in Friedel-Crafts acylation. These catalysts exhibit higher activity and tolerance to catalytic poisons compared to previously reported TfOH-treated NCI-Ti catalysts, leading to a broader substrate scope.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Ryusuke Masuda, Tomohiro Yasukawa, Yasuhiro Yamashita, Shu Kobayashi
Summary: Electrochemical allylation reactions of carbonyl compounds using cathodes prepared from nitrogen-doped carbon-incarcerated zinc catalysts have been developed. The desired allylic alcohols were obtained in high yields with low zinc leaching, suggesting the heterogeneous nature of the catalyst. Compared to bulk zinc electrodes, the nitrogen-doped carbon-stabilized zinc nanoparticle catalysts were compatible with a broader range of substrates, including heteroaromatic compounds, and enabled the use of an undivided cell.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Tatsuya Kuremoto, Ren Sadatsune, Tomohiro Yasukawa, Shu Kobayashi
Summary: A novel core/shell structure support was designed to enhance the accessibility of reaction sites, showing higher catalytic activity in asymmetric 1,4-addition reactions. This design strategy may offer a general approach for obtaining other heterogeneous catalysts with high activities.
Article
Chemistry, Physical
Fumiya Tobita, Tomohiro Yasukawa, Yasuhiro Yamashita, Shu Kobayashi
Summary: The developed catalysts can efficiently oxidize alcohols to aldehydes with high yields. Stable long-term reactions can be achieved by tuning the flow rate. Additionally, the catalysts allow for the continuous synthesis of unsaturated carbonyl compounds without isolating intermediates.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Tomohiro Yasukawa, Karin Sakamoto, Yasuhiro Yamashita, Shu Kobayashi
Summary: This study developed a catalyst with nitrogen-doped carbon as a carrier to achieve the homologation of aryl aldehydes, which showed excellent performance in terms of selectivity, activity, and reusability.
Article
Chemistry, Organic
Tomohiro Yasukawa, Hanako Nakajima, Ryusuke Masuda, Yasuhiro Yamashita, Shu Kobayashi
Summary: This study comprehensively investigated the heat-drying methods of molecular sieves for imine synthesis. It was found that drying molecular sieve 5A at 160 degrees C for 5 hours under vacuum effectively promoted the condensation reaction of ketones and amines. Only a small amount of Bronsted acid sites were crucial for the activity, rather than dehydration ability. Other types of molecular sieves could also be used after treatment with water and heat drying. Additionally, the application of activated molecular sieve 5A in the continuous-flow acetalization reaction of alcohols was demonstrated.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Tomohiro Yasukawa, Xi Yang, Yasuhiro Yamashita, Shu Kobayashi
Summary: A metal-free, heterogeneous acid catalyst has been developed for Povarov reactions. This catalyst shows excellent catalytic activity and selectivity, and has a wide range of substrate applicability. The catalytic system is heterogeneous and reusable, and has been characterized through spectroscopic and microscopic analysis.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
