Article
Chemistry, Multidisciplinary
Jin Cao, Meng-Yang Hu, Si-Yuan Liu, Xin-Yu Zhang, Shou-Fei Zhu, Qi-Lin Zhou
Summary: This study presents highly enantioselective silicon-directed Nazarov reactions cooperatively catalyzed by a Lewis acid and a chiral Bronsted acid, which allows for the synthesis of chiral cyclopentenones with diverse substituent patterns not achievable by other catalytic enantioselective reactions. The positioning of the double bond in the product is determined by the stabilizing effect of the silicon group in the dienone substrate on the beta-carbocation intermediate, and the enantioselectivity of the reaction is attributed to a chiral Bronsted acid promoted proton transfer reaction of the enol intermediate.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Marta Solas, Samuel Suarez-Pantiga, Roberto Sanz
Summary: This study describes the asymmetric synthesis of cyclopentachromenones from gold-catalyzed reaction of readily available skipped alkenynones. The cascade reaction involves an initial anti-Michael hydroarylation and a subsequent Nazarov cyclization. Excellent enantiomeric ratios and chemical yields are achieved under mild reaction conditions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Hideyuki Ishihara, Jianhao Huang, Takuya Mochizuki, Manabu Hatano, Kazuaki Ishihara
Summary: A highly enantio- and diastereoselective carbonyl-ene cyclization was developed using chiral Lewis acid-assisted chiral Bronsted acid (LBA) catalysts, demonstrating high selectivity in both standard and tandem reactions. Mechanistic examinations propose a stepwise reaction pathway involving tertiary carbocation intermediates.
Article
Chemistry, Organic
Kai Matsui, Kohei Toh, Manabu Hatano, Kazuaki Ishihara
Summary: A multiselective Diels-Alder reaction involving alpha-arylacroleins and cyclopentadiene has been developed using BBr3-assisted chiral BINOL-derived phosphoric acid catalysts. The chiral cavity of the in situ-formed acid-base cooperative catalysts plays a key role in controlling the exo- and enantioselectivity, particularly by suppressing the competitive hetero Diels-Alder reaction effectively.
Article
Multidisciplinary Sciences
Shengbiao Tang, Peng Zhang, Ying Shao, Jiangtao Sun
Summary: In this study, the authors reported a method for the synthesis of chiral allene cyclopentenones using the Nazarov cyclization reaction. By developing new substrates and conducting catalytic reactions, high yields and enantioselectivities were achieved.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Anton . Yadykov, Artem E. Eremchenko, Aleksa Milosavljevic, Alison J. Frontier, Valerii Z. Shirinian
Summary: This work describes the acid-promoted cyclization of triaryldivinyl ketones containing a thiophene moiety in the alpha-position. Two cyclization pathways are accessible, one being a 4 pi-Nazarov cyclization, and the other being a proposed 6 pi electrocyclic mechanism. The proportion of products from these pathways depends on reaction conditions and steric bulk in the substrate. Experimental and computational evidence suggests that using HCl in dioxane favors the 4 pi-conrotatory electrocyclization, while using GaCl3 in methylene chloride shifts the chemoselectivity towards a putative 6 pi-disrotatory electrocyclization. DFT calculations indicate that a complex interplay between kinetic and thermodynamic factors is involved in the chemodivergent behavior.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Jisna Jose, Thomas Mathew
Summary: 2-Cyclopentenone and its derivatives are highly esteemed synthetic intermediates with exceptional utility in organic synthesis. They are favored structural motifs in numerous pharmaceutical drugs and natural products, highlighting their significance. The review discusses the various methods used to synthesize cyclopentenones from 2016 to 2023.
Article
Chemistry, Organic
Jin Cao, Shou-Fei Zhu
Summary: In this account, we reviewed our recent efforts on the enantioselective Nazarov cyclization promoted by chiral proton-transfer shuttle catalysts. Chiral cyclopenta[b]indoles and chiral alpha, alpha' disubstituted cyclopentenones were synthesized by cooperative catalysis of a Lewis acid and a chiral spiro phosphoric acid. Mechanistic studies revealed the multifunctional role of the chiral spiro phosphoric acid as a co-catalyst for the cyclization reaction and for the enantioselective proton-transfer reaction of the enol intermediate via a hydrogen network.
Article
Chemistry, Organic
Tian-Shu Zhang, Jing Li, Hua Sun, Shuai Liu, Jing Li, Yan Chen, Wen-Juan Hao, Bo Jiang
Summary: An efficient synthetic approach for the synthesis of cyclopentenones containing a C-C stereocenter using gold(I)-catalyzed Nazarov-type cyclization/1,6-addition of 1,3-enyne esters with p-quinone methides (p-QMs) is described. This tandem transformation showed satisfactory substrate scope and acceptable functional group compatibility, providing a novel protocol for the rapid assembly of cyclopentenones in good to excellent yields under mild reaction conditions.
Article
Chemistry, Organic
Xiang-Kai Kong, Zhi-Min Xiong, Xiang Zhi, Xue-Ling Meng, Jing-Feng Zhao, Wen Chen, Hongbin Zhang
Summary: The synthesis of 2-spirocyclohexylindolines based on a Lewis acid mediated cyclization is reported. This diastereoselective procedure provides the target structures in a straightforward way via dual activation.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yi Qi, Xin Xiao, Yuqing Mei, Lingyingzi Xiong, Liheng Chen, Xuliang Lin, Zhan Lin, Shirong Sun, Bing Han, Dongjie Yang, Yanlin Qin, Xueqing Qiu
Summary: This paper presents a new strategy to tune the active sites of catalysts for the selective cleavage of lignin to produce aromatic monomers. The authors achieved this by adjusting the non-stoichiometric ratio of nickel and cobalt. The optimized Ni0.2Co2.8O4 catalysts showed outstanding catalytic conversion and selectivity for lignin cleavage.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Andreas Schneider, Christian Curado, Thomas B. Lystbaek, Silvia Osuna, Bernhard Hauer
Summary: This study uncovers the catalytic potential of squalene-hopene cyclase (SHC) and demonstrates a 397-fold improvement in catalytic performance through tailored mutations. The study also identifies terpene-induced inactivation as a major limitation and proposes a feeding strategy to overcome this limitation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Mizuki Saito, Takeshi Aihara, Hiroki Miura, Tetsuya Shishido
Summary: The study found that WO3 supported catalysts on Al2O3-TiO2 supports exhibited the highest activity and Bronsted acidity. Crystalline WO3 mainly formed on SiO2-Al2O3 and SiO2, while a high density of Lewis acid sites and surface hydroxyl groups on alumina-based supports played an important role in forming amorphous WO3 monolayer domains and generating Bronsted acid sites.
Article
Chemistry, Organic
Rohan Volpe, Hanson Y-L Law, Jonathan M. White, Bernard L. Flynn
Summary: Directed ortho-lithiation (DoL) is an effective method for the ortho-substitution of BINOL-phosphoric acid and BINOL-N-triflylphosphoramide, allowing for rapid assembly of mono- or disubstituted BINOL-P-acids, including unsymmetrical disubstitution. Most significantly, DoL has proven to be highly effective in the diastereoselective desymmetrization of pseudo-C-2-symmetric BINOL-N-triflylphosphoramide, resulting in a chiral P-group.
Article
Chemistry, Multidisciplinary
Andreas Schneider, Philipp Jegl, Bernhard Hauer
Summary: Cascade reactions provide a cutting-edge strategy for assembling complex structural scaffolds efficiently from naturally available precursors. The research introduced in this report demonstrates a method for controlling cationic cyclization cascades through designed hydrogen bonding, leading to directed cyclizations with high selectivity and yields. This approach offers a more efficient and selective way to access natural compounds such as apocarotenoids, value-added flavors, and fragrances.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Multidisciplinary Sciences
Elizabeth Garcia, Ismat Luna, Kaya L. Persad, Kate Agopsowicz, David A. Jay, Frederick G. West, Mary M. Hitt, Sujata Persad
Summary: Invasive breast cancer is predicted to affect 1 in 9 women in a lifetime, with 1 in 32 dying from the disease. The aggressive TNBC subtype is challenging to treat, highlighting the need for innovative treatment approaches. Research suggests that nitrofen and its analogues are significantly effective in limiting the invasive potential of TNBC cells.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Multidisciplinary
Waka Nakanishi, Yoshihiro Yamauchi, Yuta Nishina, Masafumi Yoshio, Masayuki Takeuchi
Summary: This study analyzed the structures and properties of multilayered films prepared from graphene oxide (GO) subjected to different oxidation processes and found that their actuation ability in response to moisture varied. Despite similar size and physical properties, the difference in macroscopic hardness between the films influenced their moisture-induced actuation.
Article
Chemistry, Multidisciplinary
Masaki Ishii, Taizo Mori, Waka Nakanishi, Jonathan P. Hill, Hideki Sakai, Katsuhiko Ariga
Summary: An air-water interface is used to control the molecular assemblies and conformations based on their intrinsic interactions and anisotropic stimuli. In this study, the researchers successfully controlled the molecular aggregated states and conformations at the interface by applying mechanical stimuli. The experiments showed that the molecular conformation and aggregated state can be changed by mechanical compression and vortex motions, providing a precise control over the molecular behavior.
Article
Pharmacology & Pharmacy
Natasha Rana, Marwa A. Aziz, Ahmed K. Oraby, Melinda Wuest, Jennifer Dufour, Khaled A. M. Abouzid, Frank Wuest, F. G. West
Summary: Deregulation and changes in energy metabolism are important biomarkers of cancer cells, and the uptake of hexoses is mediated by Glucose Transporters (GLUTs). However, some breast cancers do not show elevated glucose metabolism and may use fructose as an alternative energy source. This study explored the use of fructose mimics for early detection and improved the understanding of hexose-GLUT interactions with GLUT5 through molecular docking and dynamics simulations.
Article
Pharmacology & Pharmacy
Richard Yuen, Frederick G. West, Frank Wuest
Summary: Combining PET and fluorescence imaging techniques can optimize the treatment outcomes for tumor patients. This review discusses the recent research on integrating these two imaging capabilities into one.
Article
Chemistry, Inorganic & Nuclear
Shigehisa Akine, Keisuke Nomura, Mizuho Takahashi, Yoko Sakata, Taizo Mori, Waka Nakanishi, Katsuhiko Ariga
Summary: The number of hydrophilic triethylene glycol (TEG) chains and the structure of the hydrophobic pi-extended metallosalen core were found to influence the formation behavior and flexibility of the amphiphilic complexes at the air-water interface.
DALTON TRANSACTIONS
(2023)
Article
Biochemistry & Molecular Biology
Amanda J. Boyle, Emily Murrell, Junchao Tong, Christin Schifani, Andrea Narvaez, Melinda Wuest, Frederick West, Frank Wuest, Neil Vasdev
Summary: This study demonstrates the potential of using fluorine-18 labeled 6-fluoro-6-deoxy-D-fructose (6-[F-18]FDF) as a PET radiotracer to image microglial GLUT5 density in the brain following neuroinflammatory insult. The uptake of 6-[F-18]FDF in the ipsilateral striatum of LPS-injected rats was significantly higher compared to the contralateral striatum, while [F-18]FDG showed highest uptake at one week post-LPS injection. Immunohistochemistry confirmed the activation of microglia and astrocytes in the ipsilateral striatum. This proof-of-concept study highlights the early response of 6-[F-18]FDF to neuroinflammatory stimuli and its potential applications in neuroinflammatory and neurodegenerative diseases.
Article
Chemistry, Organic
Christian. L. Jankovic, F. G. West
Summary: Oxygenated-1,2-cyclohexadienes and their unsubstituted counterpart can be generated by fluoride-induced desilylation and undergo cycloaddition reactions with a variety of alkene traps, forming bicyclo[4.2.0]octenes. The reaction shows good regioselectivity and modest diastereoselectivity.
Article
Pharmacology & Pharmacy
Nolan Jackson, Abdulaziz Alhussan, Kyle Bromma, David Jay, James C. C. Donnelly, Frederick G. G. West, Afsaneh Lavasanifar, Michael Weinfeld, Wayne Beckham, Devika B. B. Chithrani
Summary: This study aimed to explore the use of an antimalarial drug, PYD, as a DNA repair inhibitor to enhance the DNA damage induced by RT/GNP treatment. The results showed that PYD could significantly increase DNA double-strand breaks and inhibit cell proliferation in cancer cell lines. These promising findings could lay the foundation for the clinical application of this treatment modality.
Article
Chemistry, Multidisciplinary
Christian L. L. Jankovic, Kyle C. C. McIntosh, Verner A. A. Lofstrand, F. G. West
Summary: Mild fluoride-mediated desilylative conditions generate 1,2-cyclohexadienes, which undergo efficient intramolecular [2+2] trapping to form tricyclic alkylidene cyclobutanes with complete diastereoselectivity for the cis-fused products. These cyclohexadienes can be trapped by pendent styrenes or electron-deficient olefins, and 14 substrates have been disclosed. The reactions achieve yields up to 91% at ambient temperature using only cesium fluoride and the necessary precursors are easily accessible from substituted 2-bromocyclohexenones.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Multidisciplinary Sciences
Yasser Tabana, Chih-Hsuan Lin, Dinesh Babu, Ramanaguru Siva-Piragasam, Ashley A. Ponich, Tae Chul Moon, Arno G. Siraki, Shokrollah Elahi, Richard Fahlman, Frederick G. West, Khaled Barakat
Summary: This study presents a method for identifying the cellular targets of Compound A in human peripheral blood mononuclear cells (PBMCs). By synthesizing a probe based on the chemical structure of Compound A and demonstrating its efficient binding to bovine serum albumin, this method can be used to further identify potential protein targets of small molecules in living cells. These findings provide a valuable starting point for exploring the molecular mechanisms underlying the immunomodulatory effects of Compound A.
Article
Chemistry, Physical
W. Nakanishi, Y. Matsushita, M. Takeuchi, K. Sagisaka
Summary: The conformation and alignment of molecules in organic materials are important for their bulk physical properties. In this study, the conformation and alignment of a donor-acceptor-type molecule, IBN, are investigated in both 2D and 3D assemblies using STM and X-ray crystallography. The results show that IBN has a planar conformation in both assemblies and the dipole moment is cancelled out by molecular alignment. The orientation and self-assembled structure of IBN in 2D assemblies are affected by the surface density of IBN and the crystal orientation of Au(111).
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Biochemistry & Molecular Biology
Natasha Rana, Marwa A. A. Aziz, Rabah A. T. Serya, Deena S. S. Lasheen, Nermin Samir, Frank Wuest, Khaled A. M. Abouzid, F. G. West
Summary: Rapid cell division and reprogramming of energy metabolism are crucial characteristics of cancer cells. In breast cancer, fructose can substitute glucose as an alternative energy source. GLUT5, the fructose transporter, is overexpressed in breast cancer cells, making it a valuable target for cancer detection and selective targeting of drugs. A novel fluorescence assay was used to screen and identify highly potent C-3 modified compounds as d-fructose analogues, providing avenues for the development of more potent probes targeting GLUT5-expressing cancer cells.
ACS BIO & MED CHEM AU
(2022)
Article
Chemistry, Organic
Richard Yuen, Michael Wagner, Susan Richter, Jennifer Dufour, Melinda Wuest, Frederick G. West, Frank Wuest
Summary: The study aimed to develop novel glucose-based dual imaging probes for PET and fluorescence imaging. Among the compounds tested, 2-FBDG showed favorable fluorescent properties and similar potency to 2-NBDG in competing for GLUT1 transport in breast cancer cells.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Baolei Wang, Marius-Georgian Constantin, Simarpreet Singh, Yuqiao Zhou, Rebecca L. Davis, F. G. West
Summary: Keto-substituted 1,2-cyclohexadienes were generated through base-mediated elimination and dimerized via an unprecedented formal hetero-Diels-Alder process, followed by hydration. These highly reactive cyclic allene intermediates showed high regio- and diastereoselectivity in Diels-Alder reactions, and could also react with enamine dienophiles in a hetero-Diels-Alder process.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Geeta Devi Yadav, Pooja Chaudhary, Balaram Pani, Surendra Singh
Summary: Chiral transition metal complexes with privileged ligands are efficient catalysts for various asymmetric organic transformations. Transition metal complexes of C1-symmetric pyrrolidine-based ligands have been widely used in asymmetric organic reactions. However, a comprehensive review article on the transition metal complexes of chiral C1-symmetric pyrrolidine-based ligands derived from (L)-proline has not been published.
TETRAHEDRON LETTERS
(2024)
