Article
Chemistry, Organic
Suvendu Halder, Rupa Bai Addanki, Pavan K. Kancharla
Summary: The alkene-based o-[1-(p-MeO-phenyl)vinyl]benzoates (PMPVB) donors have been successfully used for the regio- and stereoselective synthesis of C-linked indolyl glycosides under catalytic Bronsted acidic conditions. The highly reactive glycosyl donors enable the use of poorly nucleophilic N-Boc and N-acetyl indole derivatives, resulting in excellent yields and stereoselectivities of the indolyl glycosides. Furthermore, conditions for recycling the byproduct have been developed, significantly improving the potential of these donors.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Xun Zhang, Pan Sun, Yu Jiang, Saihu Liao
Summary: In this study, an efficient metal-free organic catalytic system using PADIs as catalysts has been developed for the ring-opening polymerization of ε-caprolactone. The system allows for the synthesis of poly(ε-caprolactone) with predictable molecular weight and narrow dispersity under mild conditions.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Lifeng Sun, Pradeep Chopra, Geert-Jan Boons
Summary: A new method for the synthesis of heparan sulfate oligosaccharides composed of unsulfonated fragments of different lengths was reported. Competition binding studies showed that the length of the unsulfonated fragment modulates the binding of chemokines.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Mikhail Il'in, Alexandra A. Sysoeva, Alexander S. Novikov, Dmitrii S. Bolotin
Summary: Dibenziodolium and diphenyliodonium triflates have been found to exhibit high catalytic activity in a multicomponent reaction. The study also reveals that the hydrogen atoms adjacent to the iodine atom play a dual role in forming noncovalent bonds with the substrate and increasing the electrostatic potential at the iodine atom. The higher catalytic activity of Dibenziodolium triflate can be explained by the additional energy required for the rotation of the phenyl ring in the diphenyliodonium cation during substrate ligation.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Cong-Hui Gao, Lei Yu, Xin-Yue Wu, Hong-Lin Wan, Wei Tan, Feng Shi
Summary: A tandem cyclization/addition reaction of 1,4-enediones with 2-naphthols was catalyzed by Bronsted acid, leading to the synthesis of a series of 2-furylmethylnaphthalenes with high yields (up to 98%). Control experiments provided insights into the possible reaction pathway and activation mode, contributing to the understanding of Bronsted acid catalysis and tandem reactions.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jia-Bin Pan, Zhi-Chun Yang, Xuan-Ge Zhang, Mao-Lin Li, Qi-Lin Zhou
Summary: Here, we present a method for enantioselective phosphoric acid catalyzed amination of ketenes generated from α-aryl-α-diazoketones. Mechanistic studies elucidated the reaction pathway and explained how the catalyst expedited the transformation and controlled the enantioselectivity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Gael M. Vos, Yunfei Wu, Roosmarijn van der Woude, Robert P. de Vries, Geert-Jan Boons
Summary: This paper introduces a chemo-enzymatic strategy for synthesizing poly-N-acetyl lactosamines (polyLacNAc) in a regioselective manner. The strategy involves enzymatic assembly of oligo-LacNAc chains and modification at specific positions using traceless blocking groups. The methodology allows for the synthesis of polyLacNAc chains with various topologies.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Matej Zabka, Ruth M. Gschwind
Summary: This study utilized extensive NMR spectroscopic insights to investigate the ternary complex in ion-pair catalysis, revealing unexpected hydrogen bond structures and providing valuable information for understanding the mechanisms of highly selective reactions.
Article
Chemistry, Multidisciplinary
Lea Spitzer, Sebastien Lecommandoux, Henri Cramail, Francois Jerome
Summary: An efficient method has been developed to synthesize end-functionalized oligosaccharides from unprotected monosaccharides, using a one-pot/two-step approach. The monosaccharides were first functionalized with an alkyne group at the anomeric position, then oligomerized to reach a DPn of up to 8. The obtained oligosaccharides showed complete propargylation and could be coupled to oleic acid to produce bio-based surfactants.
Article
Chemistry, Organic
Jian-Bin Lu, Shu-Yuan Liang, Wu-Tao Gui, Zhi-Chao Chen, Wei Du, Ying-Chun Chen
Summary: A relay catalytic protocol utilizing pyrrolidine and palladium catalysis has been developed for the asymmetric synthesis of 1,3-diamine derivatives from 3-substituted 1,3-dienes, sulfuric diamide, and aldehydes. This one-pot, three-component reaction offers the advantages of high atom step economy and operational simplicity, providing an efficient and straightforward access to valuable 1,3-diamines containing quaternary and tertiary stereogenic centers with moderate to good enantioselectivity.
Review
Chemistry, Multidisciplinary
Sumit K. Singh, Nidhi Mishra, Sunil Kumar, Manoj K. Jaiswal, Vinod K. Tiwari
Summary: Carbohydrates play a crucial role in organocatalysis, serving as promising scaffolds to develop potent organocatalysts and enhance productivity and selectivity of chemical reactions.
Article
Chemistry, Multidisciplinary
Martin Kamlar, Michal Urban, Jan Vesely
Summary: Over the past decade, the combination of organocatalysis and transition metal catalysis has become an important tool for synthesizing optically pure compounds with chiral quaternary centers, including spiro heterocyclic molecules. The dominant methods in enantioselective synthesis of spiro heterocyclic compounds involve chiral aminocatalysis, NHC catalysis, as well as non-covalent catalysis using chiral phosphoric acids, thiourea, and squaramide derivatives. This review article provides a summary of enantioselective methods for constructing spirocyclic heterocycles using a combination of organocatalysis and transition metal catalysis.
Article
Chemistry, Multidisciplinary
Qian Rao, Yin Zhang, Yin-Ping Liu, Bo Jiang, Xiang Wang, Tu Shu-Jiang, Wen-Juan Hao
Summary: A novel gold(I)/Bronsted acid relay catalysis enables the activation of azofuran and induces annulative rearrangement from 3-yne-1,2-diols and aryldiazonium tetrafluoroborates, resulting in the formation of furan-2-yl-substituted pyrrol-2-ones bearing a quaternary carbon center with good yields. Substituting aryldiazonium tetrafluoroborate with azofuran yields structurally identical but substituent-diverse furan-2-yl-containing pyrrol-2-ones with good yields, providing support for the crucial role of azofuran activation and annulative rearrangement by gold/Bronsted acid relay catalysis.
CHEMICAL COMMUNICATIONS
(2023)
Review
Chemistry, Multidisciplinary
Zhi-Yong Han, Liu-Zhu Gong
Summary: Asymmetric Bronsted acid catalysis is a powerful concept for asymmetric synthesis. Chiral bisphosphoric acids have received much attention in the last two decades due to their unique catalytic properties attributed to intramolecular hydrogen bonding interactions. Many structurally unique and effective bisphosphoric acids have been synthesized, exhibiting superior selectivity in a broad range of asymmetric transformations. This review provides an overview of chiral bisphosphoric acid catalysts and their applications in catalyzing asymmetric transformations.
Article
Chemistry, Multidisciplinary
Hong Jiang, Xiangxiang Zhao, Wenqiang Zhang, Yan Liu, Haiyang Li, Yong Cui
Summary: Chiral imidodiphosphates (IDPs) have been used as strong Bronsted acid catalysts, but their dynamic transformation often leads to low enantioselectivity. In this study, the topologies of metal-organic frameworks (MOFs) were utilized to control IDP conformations and local chiral microenvironments for efficient enantioselective catalysis. Two different porous Dy-MOFs were obtained from an enantiopure 1,1’-biphenol IDP-based tetracarboxylate ligand, and all IDPs were rigidified to a single O,O-syn conformation with enhanced Bronsted acidity. The more compact 4-connected IDP-based MOF exhibited high enantioselectivity in the challenging O,O-acetalization reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Yusuke Kobayashi, Yoshiji Takemoto
Article
Chemistry, Multidisciplinary
Sanae Izumi, Yusuke Kobayashi, Yoshiji Takemoto
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Chemistry, Multidisciplinary
Masato Saito, Sho Murakami, Takeshi Nanjo, Yusuke Kobayashi, Yoshiji Takemoto
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Organic
Yusuke Kobayashi, Yoshiji Takemoto
Article
Chemistry, Multidisciplinary
Yuya Nakatsuji, Yusuke Kobayashi, Sakyo Masuda, Yoshiji Takemoto
Summary: Recent interest has been directed towards organo-radical catalysts, with expectations of broadening the applications of organocatalysis. A novel radical-generating system, utilizing an azolium salt and a hydroquinone as co-catalysts, achieved oxidative C-C bond cleavage of 2-substituted cyclohexanones without the need for photoirradiation, radical initiators, or preactivated substrates. A catalytic mechanism was proposed based on diffusion-ordered spectroscopy, cyclic voltammetry measurements, and computational studies.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Ahmed G. Taha, Elghareeb E. Elboray, Yusuke Kobayashi, Takumi Furuta, Hussien H. Abbas-Temirek, Moustafa F. Aly
Summary: The 1,3-dipolar cycloaddition reactions of 2- and 3-nitrobenzaldehydes with 2-aminomethylpyridine and ethyl (2E)-2-cyano-3-(4-nitrophenyl)prop-2-enoate were found to selectively yield endo-cycloadducts as the sole products under various reaction conditions. However, 4-nitrobenzaldehyde behaved differently, producing a mixture of endo- and exo'-cycloadducts. The reaction is solvent- and temperature-dependent, and both endo- and exo'-cycloadducts were synthesized in an excellent regio-, stereo-, and chemoselective fashion. Retro-1,3-dipolar cycloadditions of the endo-cycloadducts were conducted, and mechanistic studies were carried out to support proposed mechanisms.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Takuya Murai, Wenjie Lu, Toshifumi Kuribayashi, Kazuhiro Morisaki, Yoshihiro Ueda, Shohei Hamada, Yusuke Kobayashi, Takahiro Sasamori, Norihiro Tokitoh, Takeo Kawabata, Takumi Furuta
Summary: D-2-symmetric dirhodium(II) carboxylate catalysts bearing axially chiral binaphthothiophene delta-amino acid derivatives have been developed, with conformational control supported through chalcogen-bonding interactions providing well-defined and uniform asymmetric environments. These complexes act as asymmetric catalysts for stereoselective intramolecular C-H insertion to yield various cis-alpha,beta-diaryl gamma-lactones, with high diastereo- and enantioselectivities, and can also be used for short total syntheses of naturally occurring gamma-lactones.
Article
Chemistry, Organic
Noboru Hayama, Yusuke Kobayashi, Yoshiji Takemoto
Summary: This review summarizes the first catalytic asymmetric Michael addition of heteroatomic nucleophiles to alpha,beta-unsaturated carboxylic acids. Hybrid catalysts are designed to activate the unsaturated carboxylic acids, leading to synthetic applications to biologically active compounds. The mechanistic consideration of multicomponent borate complexes is also discussed in this work.
Article
Chemistry, Analytical
Jun Haginaka, Arisa Kubo, Tetsutaro Kimachi, Yusuke Kobayashi
Summary: Monodisperse molecularly imprinted polymers (MIPs) for warfarin derivatives were prepared and their retention and molecular-recognition properties were investigated. The study revealed the important role of hydrogen bonding interactions in retention and molecular recognition.
Article
Chemistry, Organic
Shohei Hamada, Kyoko Yano, Yusuke Kobayashi, Takeo Kawabata, Takumi Furuta
Summary: The reactivity of an electronically tuned nitroxyl radical catalyst for the oxidation of cyclic benzylic ethers has been investigated. The oxidation of phthalan resulted in oxidative cleavage of the saturated ring to give an aromatic dialdehyde. Additionally, oxidation of isochromans afforded isochromanones, which are often seen in natural products, in a rapid manner.
TETRAHEDRON LETTERS
(2021)
Article
Crystallography
Tomohiro Kimura, Shohei Hamada, Takumi Furuta, Yoshiji Takemoto, Yusuke Kobayashi
Summary: Iodonium ylides with specific structures were synthesized and their halogen-bonding interactions were studied using crystal structures and calculations. The reactivity of these iodonium ylides under photoirradiation was also investigated.
Article
Chemistry, Organic
Takuya Murai, Yongning Xing, Mayu Kurokawa, Toshifumi Kuribayashi, Masanori Nikaido, Elghareeb E. Elboray, Shohei Hamada, Yusuke Kobayashi, Takahiro Sasamori, Takeo Kawabata, Takumi Furuta
Summary: A one-pot transformation method has been developed to convert biaryl dicarboxylic acids to (NH)-phenanthridinone derivatives using Curtius rearrangement and subsequent basic hydrolysis. This method is also applicable for preparing optically active amide-functionalized [7]helicene-like molecules. In addition, aza[5]helicene derivatives with a phosphate moiety were obtained as products of the Curtius rearrangement step when chalcogen atoms were present in the substrates. X-ray diffraction analysis revealed that chalcogen-bonding and pnictogen-bonding interactions may contribute to the stabilization of these compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Tomohiro Kimura, Shohei Hamada, Takumi Furuta, Yoshiji Takemoto, Yusuke Kobayashi
Summary: An efficient and scalable synthesis of N-perfluoroacy-limino-lambda(3)-iodanes was achieved through an unprecedented metathesis between iodosoarenes and perfluoroalkanenitriles. The perfluoroacy-lamino groups of the iodanes could be introduced to aromatic and heteroaromatic rings using photoirradiation.
Article
Chemistry, Organic
Takumi Inoue, Shohei Hamada, Rina Nakamura, Yusuke Kobayashi, Takahiro Sasamori, Takumi Furuta
Summary: An optically active form of an amide-functionalized thia[7]helicene-like molecule was prepared through the cyclization of the corresponding axially chiral d-amino acid. X-Ray analysis revealed its twisted helical structure with clockwise helicity and a pairwise association through hydrogen-bonding interactions.
Article
Chemistry, Organic
Yusuke Kobayashi, Sota Masakado, Takuya Murai, Shohei Hamada, Takumi Furuta, Yoshiji Takemoto
Summary: ortho-Nitro-substituted N-trifluoroacetyl imino-lambda(3)-iodane is a stable trifluoroacetyl nitrene precursor, where intra- and intermolecular halogen bonding (XB) plays a significant role, showing potential synthetic applications.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
