Article
Chemistry, Organic
Chenikkayala Siva Sankara, Shweta Bhagat, Ajeet Chandra, Irishi N. N. Namboothiri
Summary: In this study, an enantioselective desymmetrization of curcumins with 3-olefinic oxindoles involving a cascade double-Michael addition strategy was developed. The reaction provided direct access to spirocyclohexanone-oxindoles with complete regio- and diastereoselectivities and excellent enantioselectivities, besides good to excellent yields. The selectivities observed were rationalized by transitions state energy calculations at B3LYP//6-31g(d) level of DFT.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Kai-Lin Yin, Shuang Zhao, Ying Qin, Shu-Han Chen, Bo Li, Dongbing Zhao
Summary: A carbon-to-silicon switch is widely used in drug discovery. However, organosilicon compounds are not naturally occurring, so the development of effective synthetic methods is crucial for expanding their diversity. In this study, we have successfully synthesized a chiral bridged bicyclic silicon scaffold, which provides a new approach for the synthesis of chiral silicon compounds.
Article
Chemistry, Multidisciplinary
Michael J. Tilby, Damien F. Dewez, Adrian Hall, Carolina Martinez Lamenca, Michael C. Willis
Summary: In this study, the absolute configuration of sulfur-stereogenic aza-sulfur derivatives was determined using a unique feature of sulfonimidamides. Enantioselective alkylation was achieved by generating prochiral ions from sulfonimidamides with the help of a bis-quaternized phase-transfer catalyst. This demonstrates the potential of using configurationally labile aza-sulfur species in asymmetric catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Ulysse Caniparoli, Imma Escofet, Antonio M. Echavarren
Summary: Planar chiral monodentate 1,3-disubstituted ferrocene phosphines inspired by JohnPhos-type ligands have been synthesized and applied for the enantioselective gold(I) catalyzed [4 + 2] cycloaddition of 1,6-arylenynes. Computational studies elucidated the working mode of the catalyst, involving attractive noncovalent interactions that induce the folding of the substrate in the chiral environment of the ligand.
Article
Chemistry, Multidisciplinary
Min Wu, Hui Gao, Huiying Xu, Wei Yi, Zhi Zhou
Summary: The (CpRh)-Rh-X(III)-catalyzed asymmetric cascade C-H coupling/intramolecular cyclization of azomethine imines with propargyl carbonates has been developed, leading to the synthesis of a variety of chiral tetracyclic indenopyrazolopyrazolone frameworks. The study revealed the stepwise annulation process catalyzed by Rh(III) and the coordination mode of dual directing groups in tuning the selectivity.
CHINESE CHEMICAL LETTERS
(2022)
Article
Chemistry, Physical
Dekun Zhang, Ying-Bo Shao, Wansen Xie, Yunrong Chen, Wei Liu, Hanyang Bao, Faqian He, Xiao-Song Xue, Xiaoyu Yang
Summary: In this paper, a remote enantioselective desymmetrization protocol for asymmetric aromatic aminations of 9,10-dihydroacridines is disclosed. A new spirocyclic chiral phosphoric acid (CPA) catalyst is used to achieve this synthesis, leading to a wide range of chiral dihydroacridines with excellent enantioselectivities. This method is also applicable in the construction of stereogenic silicon center and kinetic resolution of unsymmetrical dihydroacridine derivatives. Density functional theory calculations elucidate the origin of the reactions' excellent regio- and enantioselectivity.
Article
Chemistry, Organic
Qiuyu Li, Rui Pan, Meihui Wang, Hequan Yao, Aijun Lin
Summary: In this study, ligand-controlled, palladium-catalyzed asymmetric [4+4] and [2+4] cycloaddition reactions of benzofuran-derived azadienes were developed. Different chiral ligands were utilized to synthesize various cyclic compounds with high enantioselectivity.
Article
Chemistry, Organic
Bin Shuai, Ping Fang, Tian-Sheng Mei
Summary: A nickel-catalyzed base-promoted rearrangement of cyclo-butanone oxime esters to cyclopropanecarbonitriles was developed, with the ring opening of cyclobutanone oxime esters occurring at the sterically less hindered side. A base-promoted nickelacyclobutane intermediate, formed in situ, is assumed to be involved in the formation of the product.
Article
Chemistry, Multidisciplinary
Xiaolei Huang, Shenghan Teng, Yonggui Robin Chi, Wenqiang Xu, Maoping Pu, Yun-Dong Wu, Jianrong Steve Zhou
Summary: The nickel-catalyzed intermolecular Heck reaction of cycloalkenes with aryl triflates, mesylates, and tosylates shows excellent enantiomeric ratios. Additionally, the asymmetric reductive Heck reaction is also applicable to a 2-cyclopentenone ketal, equivalent to conjugate arylation of the enone itself.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Shi-Jiang He, Shuai Zhu, Sheng-Qi Qiu, Wei-Yi Ding, Jun Kee Cheng, Shao-Hua Xiang, Bin Tan
Summary: This study discovered a novel type of axially chiral anthrone-derived skeleton by introducing axial chirality on symmetric anthrone skeletons through stereoselective condensation. The enantioenriched anthrones could be further transformed into dibenzo-fused seven-membered N-heterocycles with well-defined stereogenic center via Beckmann rearrangement.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Zhengshuai Xu, Chaoren Shen, Hongru Zhang, Peng Wang, Kaiwu Dong
Summary: This research achieved the construction of chiral aza-quaternary carbon centers via C-N bond formation, providing chiral dihydroquinolinone derivatives with moderate to high yield and improved enantiomeric ratio. The use of a syringe pump to add o-iodoaniline was crucial in reducing side reactions and improving chemoselectivity. By utilizing the chirality induction of an assembled aza-quaternary stereogenic center, molecules with vicinal chiral quaternary carbon centers or multiple chiral centers can be rapidly prepared.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Physical
Allen F. Prusinowski, Henry C. Sise, Taylor N. Bednar, David A. Nagib
Summary: A radical aza-Heck cyclization strategy has been developed to synthesize functionally rich products with four contiguous C-heteroatom bonds. This multicatalytic strategy enables rapid synthesis of medicinally relevant motifs and the mechanistic insights reveal the cooperation of three distinct photocatalytic cycles.
Article
Chemistry, Multidisciplinary
Hui Wang, Wangyujing Han, Adam Noble, Varinder K. Aggarwal
Summary: This study reports a nickel/photoredox-catalyzed site-selective mono-deboronative arylation of 1,2-bis-boronic esters, which allows for selective coupling of the more sterically hindered secondary/tertiary positions. This is achieved by utilizing a 1,2-boron shift of primary β-boryl radicals to the thermodynamically favored secondary/tertiary radicals for arylation. The mild conditions of this method are suitable for a wide range of aryl halides, resulting in good yields and high regioselectivity. Additionally, this method allows for stereodivergent coupling of cyclic cis-1,2-bis-boronic esters to give trans-substituted products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Woo-Ok Jung, Binh Khanh Mai, Minjin Yoo, Samuel W. J. Shields, Jason R. Zbieg, Craig E. Stivala, Peng Liu, Michael J. Krische
Summary: The mechanism of pi-allyliridium C,O-benzoate-catalyzed allylic amination was studied using various methods. The reaction showed first-order dependence on catalysts and fractional-order dependence on amines. The intervention of cesium-bridged amine dimers and the formation of cesium amide nucleophiles were observed.
Article
Chemistry, Physical
Irene Sanchez-Sordo, Andrea Chaves-Pouso, Jaime Mateos-Gil, Eva Rivera-Chao, Martin Fananas-Mastral
Summary: In this study, a new copper-catalyzed coupling reaction is reported for the enantioselective desymmetrization of chiral cycloalkenes. The method allows for the synthesis of chiral products with high regio-, diastereo-, and enantioselectivity, which can serve as versatile building blocks for the synthesis of various optically active cyclic compounds.
Article
Chemistry, Organic
Mostafa Ahmed, Mostafa Sayed, Ahmed F. Saber, Reda Hassanien, Adel M. Kamal El-Dean, Mahmoud S. Tolba
Summary: Nowadays, organic chemists are interested in heterocyclic compounds containing a pyrimidine scaffold because of their strong biological activity. In this study, new polycyclic compounds were synthesized starting from 4-chloro-9-phenyl-N-(p-tolyl)pyrimido[5',4':4,5]thieno[3,2-d][1,2,3]triazin-7-amine. The structures of the synthesized compounds were confirmed using spectral analysis techniques and elemental analysis. Among the tested compounds, compound 5 displayed the best antimicrobial activity.
POLYCYCLIC AROMATIC COMPOUNDS
(2022)
Article
Chemistry, Organic
Zhanfeng Hou, Yuena Wang, Chuan Wan, Lijuan Song, Rui Wang, Xiaochun Guo, Dongyan Yang, Yaping Zhang, Xuan Qin, Ziyuan Zhou, Xinhao Zhang, Feng Yin, Zigang Li
Summary: In this study, the first Cu-free click reaction between alkynyl sulfonium and azide at ambient temperatures in aqueous media is reported. DFT computations reveal that the sulfonium group plays a key role in enhancing reactivity by stabilizing LUMO+1 and influencing the charge distribution of the triple bond. Sulfonium alkynes can be easily synthesized and scaled up, and most of them are biocompatible. Candidate molecules were prepared and their potential use in various biological applications was tested.
Article
Chemistry, Multidisciplinary
Yun-Xuan Tan, Shijia Li, Lijuan Song, Xinhao Zhang, Yun-Dong Wu, Jianwei Sun
Summary: The first geminal hydroborative cyclization of enynes is disclosed in this study. Unlike known hydroborative cyclizations, this reaction adds hydrogen and boron to the same position, leading to a new reaction mode. By using a specific catalyst, a variety of gem-hydroborated bicyclic products with a cyclopropane unit can be rapidly formed from simple enyne substrates. Control experiments and calculations provide important insights into the reaction mechanism. Notably, two competing pathways may operate, depending on the substrate.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Guangyang Xu, Meirong Huang, Tao Zhang, Ying Shao, Shengbiao Tang, He Cao, Xinhao Zhang, Jiangtao Sun
Summary: In this study, an enantioselective insertion of a carbene into the Csp2-H bond of anisole derivatives was achieved using a chiral gold complex and a chiral phosphoric acid as the catalytic system, offering a novel approach for the synthesis of chiral α,α-diarylacetates.
Article
Chemistry, Organic
Mahmoud S. Tolba, Mahmoud M. Hamed, Mostafa Sayed, Adel M. Kamal El-Dean, Shawkat A. Abdel-Mohsen, Omneya A. Ibrahim, Walid A. M. Elgaher, Anna K. H. Hirsch, Abdelreheem Abdelfatah Saddik
Summary: In this study, a facile procedure for synthesizing new diclofenac analogous was presented. The chemical structures of the synthesized compounds were confirmed using elemental and spectral analysis techniques. The synthesized compounds showed moderate to high in-vitro antimicrobial activity, and a molecular docking approach was used to investigate their molecular mechanism.
POLYCYCLIC AROMATIC COMPOUNDS
(2023)
Article
Chemistry, Multidisciplinary
Zhicheng Bao, Meirong Huang, Yan Xu, Xinhao Zhang, Yun-Dong Wu, Jianbo Wang
Summary: Bisborylalkanes are versatile bifunctional reagents in organic synthesis, with the ability to selectively convert their two boron moieties into other functional groups. This study presents a new strategy for synthesizing bisborylalkanes through the reaction of N-trisylhydrazones with diboronates, resulting in the transformation of bis(boryl) methane into 1,2-bis(boronates) through formal carbene insertion. This practical synthesis method allows for the broad substrate scope of 1,2-diboronates by readily deriving N-trisylhydrazones from corresponding aldehydes. Mechanistic studies uncover an unusual neighboring group effect of 1,1-bis(boronates) that explains the observed regioselectivity when unsymmetric 1,1-diboronates are utilized.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Materials Science, Multidisciplinary
N. Almutlaq, Mahmoud M. Elshanawany, Mostafa Sayed, Osama Younis, Mostafa Ahmed, Josef Wachtveitl, Markus Braun, Mahmoud S. Tolba, Ahmed F. Al-Hossainy, Amina A. Abozeed
Summary: New compounds of (E)-1-(3-chloro-1H-indol-2-yl)-N-(4-methoxyphenyl)methanimine [Indol-M] and (E)-1-(4(((3-chloro-1H-indol-2-yl)methylene)amino)phenyl)ethan-1-one [Indol-A] were synthesized and converted to thin films using physical vapor deposition technique. Characterization techniques including FTIR, NMR, XRD, SEM, and optical spectroscopy were employed. The XRD and FTIR spectra were confirmed by TDDFT calculations. The thin films exhibited one-dimensional morphological structure and direct optical energy bandgaps of 4.49 eV and 3.31 eV for [Indol-M]TF and [Indol-A]TF, respectively. The optical properties predicted by CASTEP TDDFT agreed well with experimental values. [Indol-M]TF and [Indol-A]TF are promising materials for optoelectronics and solar cell applications.
CURRENT APPLIED PHYSICS
(2023)
Article
Physics, Applied
Amina Abozeed, Mahmoud S. Tolba, Mostafa Sayed, Ahmed F. Al-Hossainy, Osama Younis
Summary: A thin film of 7-oxo-thiazolopyrimidine-3,8-dicarbonitrile derivative was prepared and studied for its surface morphology and molecular structure using various techniques. Quantum chemical calculations were also carried out to investigate some reactivity descriptors. Heterojunction diodes were fabricated and the energy bandgap value of the organic thin film falls within the semiconductor material range. The material has potential applications as an antireflection coating for solar cells and lenses with a wide focal range. The blue luminescent thiazolopyrimidine compound exhibits a notable blue shift in its emission in the more aggregated state, which can be understood through structural analyses. The molecule's chemical structure enables it to interact with both itself and the polar solvent, resulting in the bending of the conjugated plane and the observed blue shift. The molecule also gives different emission colors depending on the molecular packing.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Mahmoud M. Hamed, Mostafa Sayed, Shawkat A. Abdel-Mohsen, Abdelreheem Abdelfatah Saddik, Omneya A. Ibrahim, Adel M. Kamal El-Dean, Mahmoud S. Tolba
Summary: In recent years, the synthesis of diclofenac derivatives has gained increasing interest due to their exceptional biological activity. This study presents the synthesis of novel diclofenac derivatives through simple synthetic procedures. These derivatives showed satisfactory in-vitro antibacterial activity against different strains of bacteria, and molecular docking study was conducted to investigate their mode of action.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Article
Chemistry, Multidisciplinary
Yong Wang, Yuxuan Li, Lei Wang, Shengtao Ding, Lijuan Song, Xinhao Zhang, Yun-Dong Wu, Jianwei Sun
Summary: In this study, a new method for efficient construction of gem-diboryl compounds with hetero-substituted carbon centers was developed. This method involves the alpha-dihydroboration of heteroalkynes and is a practical and atom-economic alternative to the conventional multistep synthetic strategy.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Organic
Fady Youssef Fathy Soltan, Mostafa Sayed, Mohamed Abdul Tawab, Satish Kumar Talloj, Adel M. Kamal M. El-dean, Mahmoud S. Tolba, Abdelreheem Abdelfatah Saddik
Summary: Heterocyclic compounds are fundamental in medicinal chemistry and have numerous applications in our daily lives. Many heterocyclic compounds with interesting biological and pharmacological properties have been reported in the literature. However, the emission intensity of aromatic pi-conjugated heterocyclic molecules is quenched due to aggregation caused by pi-pi stacking. To overcome this limitation, the design and function of aggregation-induced emission (AIE) active heterocyclic materials have emerged. AIE has been used to enhance the emission intensity and stability of compounds, with potential applications in chemical sensing and bioimaging. This work comprehensively reviews recent progress in AIE-active heterocyclic compounds used in chemo-selective and bio-imaging applications, as well as highly selective sensors.
JOURNAL OF HETEROCYCLIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Ke Liao, Cho Ying Chan, Siqi Liu, Xinhao Zhang, Jiean Chen, Yong Huang
Summary: Functionalizing molecules through selective cleavage of carbon-carbon bonds is a promising approach, but the selective cleavage of inert C-sp3-C-sp3 bonds in hydrocarbon feedstocks remains challenging. This article presents a straightforward protocol for cleavage and functionalization of C(sp3)-C-sp3 bonds in alkylbenzenes using photoredox catalysis. Our method utilizes two distinct bond scission pathways depending on the nature of the benzylic substituents. This strategy provides a practical means of cleaving inert C-sp3-C-sp3 bonds in molecules without heteroatoms, generating various radical species.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Linxing Zhang, Ping Chen, Xue-Peng Zhang, Chengxi Yang, Tian-Yu Sun, Xinhao Zhang, Yun-Dong Wu
Summary: The Catellani-type palladium/norbornene-cocatalyzed ortho-amination of aryl halides is widely used, but some key issues remain unresolved. Mass spectrometry and theoretical studies reveal the presence of a Cs-containing Pd-IV complex, the reactivity difference between 2-iodotoluene and morpholine-OBz, the coordination preference of Cs2CO3, the favored formation of Pd-IV intermediate with involvement of Cs2CO3, and the lower yield when using K2CO3 as a base.
Article
Engineering, Marine
Xinhao Zhang, Meng Zhou
Summary: This study proposes a method to build a general CNN model that can reconstruct images in unfamiliar areas. The model uses a more flexible U-net architecture to improve generality and was trained on images of different shapes to enhance performance. Results show that the model outperforms traditional interpolation methods when reconstructing for unfamiliar areas.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Hong-Cheng Shen, Mihai V. Popescu, Ze-Shu Wang, Louis de Lescure, Adam Noble, Robert S. Paton, Varinder K. Aggarwal
Summary: We report an iridium-catalyzed asymmetric alkylation-induced 1,2-metalate rearrangement of bicyclo[1.1.0]butyl boronate complexes enabled by strain release. This method allows for the asymmetric difunctionalization of C-C bonds, including dicarbonation and carboboration, providing a variety of enantioenriched three-dimensional cyclobutane products. The diastereoselectivity of the reaction has been rationalized based on experimental data and density functional theory calculations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
