Article
Chemistry, Organic
Fei Zhao, Xin Gong, Yangbin Lu, Jin Qiao, Xiuwen Jia, Hangcheng Ni, Xiaowei Wu, Xiaoning Zhang
Summary: This method reports the controlled divergent synthesis of tetrasubstituted 1,3-enynes and alkynylated 3H-pyrrolo[1,2-a]indol-3-ones through rhodium-catalyzed reactions, featuring excellent selectivity, broad substrate scope, moderate to high yields, and good functional group compatibility under mild redox-neutral conditions.
Review
Chemistry, Multidisciplinary
Ryan T. Davison, Erin L. Kuker, Vy M. Dong
Summary: The article discusses the application of transition metal catalysis in carbon-hydrogen bond activation and the research results in carbonylation reactions, including hydroacylation and hydroacylation of carbonyls. The studies demonstrate that transition metal catalysts can promote C-C and C-O bond-forming reactions, as well as C-C bond-cleaving processes.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Suchen Zou, Bangkui Yu, Hanmin Huang
Summary: An efficient strategy for preventing beta-hydride elimination of alkylpalladium species by ligating palladium with adjacent amino group was developed, enabling a novel palladium-catalyzed ring-closing aminoalkylative amination of unactivated aminoenynes. The reaction is applicable to aminals and aliphatic aldehydes with secondary amines, providing straightforward access to structurally diverse exocyclic allenic amines with 5 to 12-membered N-heterocycles. A chiral phosphoramidite-ligated palladium complex was used as the catalyst to achieve an enantioselective variant with up to 93% ee. Synthetic transformations of the chiral products also resulted in structurally unique spirodiamines, including one pharmaceutically active molecule, through axial-to-central chirality transfer.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Yulin Han, Anni Qin, Qian Zhang, Xue Zhang, Hui Qian, Shengming Ma
Summary: The Rh-catalyzed reaction allows for the efficient synthesis of cis-fused bicyclic products with excellent selectivity and tolerance towards synthetically useful functional groups. The proposed mechanism involves the rapid racemization of the allene moiety in the starting materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Zhengtian Ding, Yiming Wang, Wenfeng Liu, Yate Chen, Wangqing Kong
Summary: The study presents an unprecedented nickel-catalyzed one-pot synthesis of enantioenriched spiroindanones from readily available 1,6-enynes and o-formylarylboronic acids. The reaction proceeds smoothly under redox-neutral conditions, demonstrating excellent regio-, enantio-, and diastereoselectivity with a broad substrate scope.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Yanhua Hu, Yashi Zou, Huiwen Yang, Haotian Ji, Yue Jin, Zhenfeng Zhang, Yangang Liu, Wanbin Zhang
Summary: Asymmetric sequential hydrogenations of conjugated enynes have been developed using a Ph-BPE-Co-I catalyst for the precise synthesis of chiral Z-allylamides with high activity and excellent enantioselectivity. The difference in catalytic activity between cobalt complexes of Ph-BPE and QuinoxP* was explained by the process decomposition of rate-determining step in the second hydrogenation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Ken-Loon Choo, Bijan Mirabi, Karl Z. Demmans, Mark Lautens
Summary: Enantioenriched spiro-oxiranes with three contiguous stereocenters were synthesized using a rhodium-catalyzed cascade reaction, enabling the formation of a spirocyclic framework in a single step. Both sp(2)- and sp-hybridized carbon nucleophiles were found to be efficient initiators, yielding products with different functional groups. Derivatization studies demonstrated the synthetic versatility of the products' epoxide and alkyne moieties. DFT calculations were employed to explain spectroscopic discrepancies between solution- and solid-state structures of the products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Undamatla Suri Babu, Maneesh Kumar Reddy Singam, Muniganti Naveen Kumar, Jagadeesh Babu Nanubolu, Maddi Sridhar Reddy
Summary: This article presents a general approach to the synthesis of napthyridinones through the Pd-catalyzed annulation of 1,6-enynes with 2-iodoanilines. The protocol involves a rare carbo-aminative cyclization via the 6-endo-trig mode, and overcomes the commonly observed exo-trig/dig cyclizations. The regioselective aryl palladation of alkyne followed by intramolecular Heck-type reaction enables the cascade synthesis.
Article
Chemistry, Organic
Jian-Qiang Chen, Qi Chen, Baofu Chen, Jie Wu
Summary: A direct photoredox catalyzed radical-triggered tandem cyclization of 1,7-enynes with alkyloxalyl chlorides is developed, enabling the preparation of dihydropyranones containing all-carbon quaternary centers through alkoxycarbonylation/6-exo-dig cyclization/6-endo-trig cyclization with 1,7-enynes under mild conditions. Importantly, this approach provides a new route to polysubstituted dihydropyranones.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Physical
Jumpei Hirose, Takumi Wakikawa, Shun Satake, Masahiro Kojima, Manabu Hatano, Kazuaki Ishihara, Tatsuhiko Yoshino, Shigeki Matsunaga
Summary: The enantioselective intramolecular oxyamination of unsaturated alkoxyamines was achieved using a hybrid catalytic system consisting of Cp*Rh-III/chiral disulfonate/CuOAc, leading to tetrahydrofuran derivatives with a tetrasubstituted chiral center in high enantioselectivity. The use of a sterically hindered chiral disulfonate and a Cu additive was crucial for the success of the reaction.
Article
Chemistry, Multidisciplinary
Mary Katherine Andrews, Xinyu Liu, Samuel H. Gellman
Summary: Using a tunable molecular scaffold, this study demonstrates the importance of aligning reactive diads for bifunctional catalysis. It is found that an aligned pair of primary amine groups is uniquely competent for catalyzing crossed aldol condensations with an aryl aldehyde as the electrophile. The findings highlight the critical role of the foldamer scaffold in catalytic efficacy.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
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, Multidisciplinary
Jiangyan Tian, Wendian Li, Ruihao Li, Lin He, Hui Lv
Summary: The nickel/(S)-t-Bu-PHOX complex catalyzed asymmetric arylative cyclization of N-alkynones has successfully delivered 1,2,3,6-tetrahydropyridines containing a chiral tertiary alcohol in high yields and excellent enantioselectivities, providing efficient access to chiral tetrahydropyridine and piperidine analogues.
CHINESE CHEMICAL LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Shivam A. A. Meena, Poonam Sharma, Akhilesh K. K. Verma
Summary: A transition-metal-free one-pot synthesis of di-functionalized succinimides has been developed, which involves a radical cascade seleno/thiosulfonation of aza-1,6-enynes in an atom economical manner. This method allows the synthesis of highly decorated succinimides with excellent stereoselectivity under mild reaction conditions. The proposed radical pathway is well supported by control experiments. The reaction demonstrates advantageous features including operational simplicity, atom economy, and broad substrate scope.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Shi-Yin Tian, Jing-Jing Ai, Jia-Hui Han, Weidong Rao, Shu-Su Shen, Daopeng Sheng, Shun-Yi Wang
Summary: A photocatalytic synthesis method was developed to simultaneously construct two C-S/Se bonds and one C-C bond without the use of transition metals or other additives, using diphenyl disulfide or diphenyl diselenide as sulfur or selenium sources.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Tomoaki Murakami, Keiichi Noguchi, Naomi Hachiya, Fuyuki Kametani, Masayoshi Tasaki, Satoshi Nakaba, Yukiko Sassa, Taro Yamashita, Konen Obayashi, Yukio Ando, Masao Hamamura, Takeshi Kanno, Kazufumi Kawasako
AMYLOID-JOURNAL OF PROTEIN FOLDING DISORDERS
(2020)
Article
Chemistry, Organic
Hiroto Takahashi, Yusaku Honjo, Yu Shibata, Yuki Nagashima, Ken Tanaka
Summary: The dienylation of unfunctionalized arenes with 1,6-diynes, possessing aryl groups at the diyne termini, was found to proceed in the presence of an electron-deficient cyclopentadienyl rhodium(III) complex and a stoichiometric amount of silver carbonate. Experimental and theoretical mechanistic studies indicated the possible catalytic role of a (CpRh)-Rh-E(I) complex generated in situ in this reaction.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Multidisciplinary
Masahiro Kubo, Keiichi Noguchi, Koji Nakano
Summary: Chiral spiro pi-conjugated compounds, including a chiral benzo[b]silole-fused SBF and a pi-extended spiro polycyclic arene, have been synthesized and studied for their optical properties. These compounds exhibit circularly polarized luminescence with dissymmetry factors up to 0.76x10(-3). Experimental and theoretical analyses show that the emission of these compounds occurs from specific subunits, with slightly different structures compared to the Frank-Condon state.
Article
Biochemistry & Molecular Biology
Yosuke Inoue, Yuya Hanazono, Kentaro Noi, Akihiro Kawamoto, Masato Kimatsuka, Ryuhei Harada, Kazuki Takeda, Ryoichi Kita, Natsuki Iwamasa, Kyoka Shibata, Keiichi Noguchi, Yasuteru Shigeta, Keiichi Namba, Teru Ogura, Kunio Miki, Kyosuke Shinohara, Masafumi Yohda
Summary: A study on CtHsp104 revealed that in the presence of ADP, it assembles into a left-handed spiral filament with a hexamer of split spiral structures. Staggered and split hexameric rings were observed in cryo-EM images, and substrate addition was found to enhance the conformational change and increase the frequency of the split structure.
Article
Soil Science
Akira Takamoto, Yohey Hashimoto, Maki Asano, Keiichi Noguchi, Rota Wagai
Summary: The study investigated the distribution and chemical species of phosphorus in relation to iron and aluminum phases in two Andisols, revealing a stronger control of aluminum phases over phosphorus compared to iron phases. Phosphorus was primarily associated with aluminum, with organic and inorganic phosphorus reservoirs being important in low- to meso-density fractions in Andisols.
Article
Crystallography
Hiroaki Litsuka, Kun Li, Miyuki Kobayashi, Kikuko Lida, Keiichi Noguchi, Noriyuki Yonezawa, Akiko Okamoto
Summary: The crystal of the compound has a monoclinic structure with cell parameters a=10.3707 angstrom, b=12.0232 angstrom, c=15.7744 angstrom, and β=90.907 degrees, at a temperature of 193.15K.
ZEITSCHRIFT FUR KRISTALLOGRAPHIE-NEW CRYSTAL STRUCTURES
(2021)
Article
Chemistry, Multidisciplinary
Naofumi Naga, Keiichi Noguchi, Tomoaki Kouya, Kei Nishii
Summary: Syndiotactic-polystyrene based porous polymers were successfully obtained by polymerizations of styrene, 4-methyl styrene, or 4-tert-butyl styrene and copolymerization of St/MeSt, St/BuSt, or St/DVB using a half metallocene catalyst and methylaluminoxane. The resulting polymers exhibited lower bulk densities and a porous structure formed by networked fibers.
Article
Biochemistry & Molecular Biology
Tomonori Saotome, Sawaros Onchaiya, Subbaian Brindha, Taichi Mezaki, Satoru Unzai, Keiichi Noguchi, Jose C. Martinez, Shun-ichi Kidokoro, Yutaka Kuroda
Summary: The third PDZ domain of PSD95 has a propensity to form amyloid fibrils at high temperatures. It exhibits reversible oligomerization at high temperatures, which is unusual for a small globular protein like PDZ3. By suppressing the high-temperature oligomerization, amyloid formation can be inhibited.
Article
Biochemistry & Molecular Biology
Nina Kurokawa, Rio Midorikawa, Manami Nakamura, Keiichi Noguchi, Ken Morishima, Rintaro Inoue, Masaaki Sugiyama, Masafumi Yohda
Summary: The study examined the oligomeric structural change of CgHspB1 using sedimentation velocity analytical ultracentrifugation. It was found that at low temperatures, CgHspB1 exists as an 18-mer and is relatively unstable, partially dissociating into smaller oligomers. At elevated temperatures, the 24-mer is more stable and in dynamic equilibrium with the dissociated oligomers in the hexameric unit. Additionally, the disulfide bond between conserved cysteine residues plays a role in stabilizing the hexamers.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Biochemistry & Molecular Biology
Yosuke Fukutani, Yuko Nakamura, Nonoko Muto, Shunta Miyanaga, Reina Kanemaki, Kentaro Ikegami, Keiichi Noguchi, Ikuroh Ohsawa, Hiroaki Matsunami, Masafumi Yohda
Summary: Vertebrate animals detect odors through olfactory receptors, but the studies of their odor molecule recognition mechanisms have been hindered by the difficulty in their expression in heterologous cells. However, this study found that a single amino acid substitution in conserved amino acid residues of RTP-independent ORs can significantly improve their functional expression in heterologous cells.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Polymer Science
Naofumi Naga, Shingo Okado, Yui Ohara, Keiichi Noguchi
Summary: Poly(p-phenylene alkylene)s were successfully synthesized through Kumada coupling reaction, showing moderate yields and various properties depending on the choice of alpha,omega-dibromoalkane. X-ray diffraction and FT-IR analyses revealed differences in crystal structures among the polymers. Poly(p-phenylene co-alkylenes)s were newly prepared with lower melting temperatures compared to corresponding poly(p-phenylene alkylene)s. The WAXD profiles of the co-alkylene polymers demonstrated a mix of characteristics from the individual alkylene polymers, influenced by the feed ratios of the alpha,omega-dibromoalkanes.
JOURNAL OF POLYMER RESEARCH
(2022)
Article
Biochemistry & Molecular Biology
Keisuke Uematsu, Chikara Hayasaka, Ko Takase, Keiichi Noguchi, Koji Nakano
Summary: This study reported a method to synthesize [7]helicenes and [7]helicene-like compounds from thia[7]helicene as a common starting material, including silole- and phosphole-fused compounds, cyclopentadiene-fused compounds, and aza[7]helicenes. The synthesized compounds showed unique absorption and emission properties, with slightly red-shifted absorption for silole-fused compounds and strong violet emission for cyclopentadiene-fused compounds and aza[7]helicenes. Additionally, aza[7]helicenes displayed circularly-polarized luminescence with specific dissymmetry factors.
Article
Biochemistry & Molecular Biology
Koji Nakano, Ko Takase, Keiichi Noguchi
Summary: A new family of spiro-fused polycyclic aromatic compounds containing a furan unit was designed and successfully synthesized in enantiopure form. The properties of these furan-containing compounds, including absorption and emission, were found to be different from their thiophene analogs. Additionally, all of these compounds exhibited circularly polarized luminescence.
Article
Soil Science
Shoko Uchida, Yohey Hashimoto, Akira Takamoto, Keiichi Noguchi, Wantana Klysubun, Shan-Li Wang
Summary: This study investigates the adsorption behavior of allophane and ferrihydrite in volcanic ash soils with regards to phosphate. The results show that allophane has a higher affinity for phosphate compared to ferrihydrite, especially at low to intermediate concentrations. Additionally, the study finds that precipitation of Al-phosphate occurs in allophane and allophane-ferrihydrite mixtures.
SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
(2022)
Article
Chemistry, Organic
Daisuke Sato, Akira Tsubouchi, Yuichiro Watanabe, Keiichi Noguchi, Kazunori Miyamoto, Masanobu Uchiyama, Akio Saito
Summary: The activation of alkyne pi-bonds by transition metal complexes is well studied for the cycloisomerization of enynes into bicyclo[3.1.0]hexanes, enabling the introduction of carbon and oxygen functional groups. However, the cycloisomerization of enynones through the activation of carbonyl groups into bicyclo[3.1.0]hexanes has not yet been achieved. In this study, we report the aluminum halide-mediated cycloisomerization of 7-en-2-ynones into halogenated bicyclo[3.1.0]hexanes.
ORGANIC CHEMISTRY FRONTIERS
(2023)