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Synergistic silver-mediated and palladium-catalyzed nondirected olefination of aryl C–H bond: quick access to multi-substituted aryl olefins

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Science China Chemistry 2024年第3期67卷 882-889页

作者： Jian Yao Lili Shao Xiaohong Huo Xiaoming Wang Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Frontiers Science Center for Transformative MoleculesSchool of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 20032China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

Transition metal-catalyzed olefination of aryl C-H bond is a powerful tool for the synthesis of alkenes. While the Pd-catalyzed oxidative C-H olefination of arenes, also known as Fujiwara-Moritani reaction, has been established as one of the most efficient methods, the substrates are largely limited to terminal olefins with electron-withdrawing group(s). Herein, we report a synergistic silver-mediated and palladium-catalyzed non-directed C-H olefination of arenes with vinyl(pseudo)halides, which offers a complementary strategy to the typical Fujiwara-Moritani reaction. The reactions proceeded well for a variety of halogenated arenes, heteroarenes, and olefin substrates, providing an efficient access to various multi-substituted aryl olefins, including trisubstituted/tetrasubstituted olefins and several complex olefins derived from medicines or natural products. Mechanistic studies indicated a bimetallic Pd/Ag cooperation is operative in the catalysis, i.e., the reaction is initiated by aryl C-H bond cleavage via ligation with phosphine/Ag species, followed by transferring of the aryl moiety to a vinyl palladium intermediate,which is in turn formed by oxidative addition of vinyl(pseudo)halide to a Pd complex. This method enables the synthesis of a wide range of challenging multi-substituted vinyl products from simple arenes(directing-group free) in a streamlined and controllable fashion.

关键词： direct C–H olefination multi-substituted aryl alkenes bimetallic Pd/Ag cooperation C–H functionalization

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Catalytic behavior of Mo-Bi-Fe-Co-K-M-O(M=Ce,Gd,CeGd)catalysts for selective oxidation of isobutene

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Journal of Rare Earths 2024年第1期42卷 84-93,I0003页

作者： Qinghui Li Huahua Zhao Jian Yang Jun Zhao Liang Yan Huanling Song Lingjun Chou State Key Laboratory for Oxo synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China University of Chinese Academy of Sciences Beijing100049China

The further improvement of methacrolein(MAL)selectivity from isobutene(IB)oxidation is crucial and *** this study,based on the typical Mo-Bi-Fe-Co-K-O mixed metal oxide,the rare earth element Gd-doped,Ce-doped and CeGd co-doped catalysts were prepared by co-precipitation strategy to increase the selectivity of MAL from 47.9%to 49.8%,64.2% and 68.6%,*** order to elucidate in-depth the promoting effect of Ce and/or Gd,various characterizations were utilized including X-ray diffraction patterns(XRD),Raman,X-ray fluorescence spectrometry(XRF),X-ray photoelectron spectroscopy(XPS),O_(2)-temperature programmed desorption(O_(2)-TPD),H2-temperature programmed reduction(H2-TPR),CO_(2)-temperature programmed desorption(CO_(2)-TPD),IB-temperature programmed desorption(i-C4-TPD)and in-situ IB-Fourier transform infrared spectroscopy(IB-FTIR).Both Ce and Gd finely regulate the bulk and surface structure of the catalyst,thus altering the redox ability,oxygen mobility and storage ability and *** with Ce,Gd addition slightly regulates the variation of Co^(2+)/Co^(3+)redox couples,greatly enhances the interaction among the components on the catalyst,thus only increases the content of surface oxygen species and has little effect on their *** Cecontaining catalyst performs stronger oxygen storage and migration ability,thus leading to the overproduction of surface Odefectspecies,which are proposed to be the active sites for the production of MAL and *** CeGd co-doped catalyst possesses the proper content of surface Odefectspecies,thus exhibits much higher MAL ***,the promoting mechanism of Ce and/or Gd over IB oxidation is ***,this work is helpful for understanding the influence of rare earth elements on the structure of mixed metal oxides and the olefin selective oxidation reaction.

关键词： Mixed metal oxide catalyst Rare earth element Isobutene Selective oxidation Methacrolein

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Efficient capture of difluorocarbene by pyridinium 1,4-zwitterionic thiolates:A concise synthesis of difluoromethylene-containing 1,4-thiazine derivatives

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Chinese Chemical Letters 2024年第4期35卷 367-370页

作者： Zhiwei Chen Heyun Sheng Xue Li Menghan Chen Xin Li Qiuling Song institute of Next Generation Matter Transformation College of Materials Science&Engineering and College of Chemical Engineering at Huaqiao UniversityXiamen 361021China Fujian University Key Laboratory of Molecule synthesis and Function Discovery College of ChemistryFuzhou UniversityFuzhou 350108China State Key Laboratory of Organometallic Chemistry and Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

A practical method for the construction of difluoromethylene-containing 1,4-thiazine moieties using readily available diethyl bromodifluoromethanephosphonate(BrCF_(2)PO(OEt)_(2))as difluorocarbene precusor has been *** transformation features the efficient capture of difluorocarbene by pyridinium 1,4-zwitterionic thiolates.A series of structurally novel and functionalized difluoromethylene-containing 1,4-thiazine derivatives were thus synthesized in good yields.

关键词： Difluoromethylene Pyridinium 1 4-zwitterionic thiolates 1 4-Thiazine derivatives

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Modulating the alloying mode in the doping-induced synthesis of Au-Pd nanowires

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Nano Research 2024年第4期17卷 3334-3343页

作者： Hui Jin Xiaoliang Wei Lecheng Zhao Jialong Yu Qiao Pan Shumin Li Qian Wang Zhaotong Yuan Dan Yang Donghui Zhao Hongyu Chen Yawen Wang institute of Advanced synthesis School of Chemistry and Molecular EngineeringJiangsu National Synergistic Innovation Center for Advanced MaterialsNanjing Tech UniversityNanjing 211816China School of Science Westlake UniversityHangzhou 310064China institute of Natural Sciences Westlake Institute for Advanced StudyHangzhou 310064China

Heterogeneous doping is one effective strategy for synthesizing metal alloy ***,the heterogeneous doping processes of Pd on the ultrathin Au nanowires were systematically modulated and ***-Pd alloy nanowires with various morphologies and lattice structures can be obtained by adjusting the morphology of the precursor Au nanowires and the kinetics of the heterogeneous doping *** effects of the rate of Pd reduction and the concentration of the ligand oleylamine(OAm)on the Pd deposition and alloying mode were ***,as the Pd deposition rate decreases,the Pd deposition and alloying mode switches from the island-forming Stransky–Krastanov(SK)mode to the epitaxial Frank-van der Merwe(FM)mode,and eventually to an unconventional twisting alloying mode,where the interdiffusion of Pd and Au causes drastic rearrangement of the lattice structure and formation of helical *** kinetics-related variation of alloying mode could also be observed in the Au-Ag nanowires,demonstrating a general design principle for the synthesis of alloy *** addition,the electrocatalytic performance of various Au-Pd nanowires was evaluated,and the alloy nanowire formed via the SK mode was found to be an excellent electrocatalyst for oxygen reduction and ethanol oxidation.

关键词： gold nanowires Au-Pd alloy oleylamine post-synthetic modification

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Hydrodechlorination of trifluoro-trichloroethane to chlorotrifluoroethylene:Revealing the deactivation mechanism and regeneration strategy of Pd-Cu/AC catalyst

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Chinese Journal of Chemical Engineering 2024年第6期70卷 261-268页

作者： Song Tian Yicheng Chen Xiaoyu Wen Bingcheng Li Jian Lu Zile Li Feng Feng Qingtao Wang Qunfeng Zhang Xiaonian Li State Key Laboratory Breeding Base of Green Chemistry synthesis Technology Institute of Industrial Catalysis of Zhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Fluorine&Nitrogen Chemicals Xi'an Modern Chemistry Research InstituteXi'an 710065China

Chlorotrifluoroethylene(CTFE)is a vital fluorinated olefinic monomer produced through the catalytic hydrodechlorination of trichlorotrifluoroethane(CFC-113),an eco-friendly ***,hydrodechlorination catalysts for olefin production often suffer from poor *** Pd/AC catalyst and Pd-Cu/AC catalyst prepared by co-impregnation method exhibited poor stability,Pd-Cu/AC catalyst with CFC-113 conversion dropping to around 37%after 50 h of hydrodechlorination ***-Emmett-Teller,transmission electron microscopy,X-ray photoelectron spectroscopy,and X-ray diffraction of fresh and deactivated Pd/AC catalysts indicate that the deactivation of Pd/AC catalysts is due to high-temperature agglomeration of *** analysis of fresh and deactivated Pd-Cu/AC catalysts using Brunauer-Emmett-Teller,transmission electron microscopy,and thermogravimetric analysis techniques revealed decreased dispersion of active sites,reduced surface area,catalyst aggregation deactivation,and a significant decrease in Cu ***,the results of NH3-TPD revealed that the acid sites of the catalyst increased significantly.X-ray diffraction spectra indicated the formation of new species,basic copper chloride(Cu_(2)(OH)_(3)Cl),during the *** the reaction progressed,these new species agglomerated,leading to a gradual loss of catalyst ***,the deactivated catalyst was successfully reactivated using a simple alkaline washing method.

关键词： CFC-113 Hydrodechlorination Chlorotrifluoroethylene Catalyst deactivation

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Total synthesis of Laurane and Guaiane Sesquiterpenoids via Oxidative Nazarov Reaction

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Chinese Journal of Chemistry 2024年第11期42卷 1267-1274页

作者： Yuye Chen Wenqing Chen Zhiting Zhang Jing Xu Shenzhen Grubbs institute and Department of Chemistry and Guangming Advanced Research institute and Guangdong Provincial Key Laboratory of Catalysis and Shenzhen Key Laboratory of Small Molecule Drug Discovery and synthesis Southern University of Science and TechnologyShenzhenGuangdong518055 China

As one of the most common structural motifs in natural products,cyclopentenones usually can be fabricated by Nazarov cyclization using divinyl ketones or functionalized tertiary divinyl carbinols(TDCs)as ***,straightforward method for transforming unfunctionalized TDCs to their corresponding cyclopentenones is currently ***,we wish to report the total syntheses of four structurally distinct terpenoids,namely laurane-type marine sesquiterpenoids isolaurene,debromoaplysin and aplysin,and guaiane sesquiterpenoid guaiadienone A,all using a novel synthetic method,named oxidative Nazarov cyclization,as the key *** work demonstrated our robust method is suitable for synthesizing various highly substituted cyclopentenones.

关键词： Total synthesis Synthetic methods Sesquiterpenoids Oxidative Nazarov reaction Electrocyclization Oxoammonium salt Pericyclic reaction Annulation

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Strategies for constructing seven-membered rings:Applications in natural product synthesis

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Chinese Chemical Letters 2024年第6期35卷 53-70页

作者： Peng Chen Lijuan Liang Yufei Zhu Zhimin Xing Zhenhua Jia Teck-Peng Loh College of Advanced Interdisciplinary Science and Technology Henan University of TechnologyZhengzhou 450001China Division of Chemistry and Biological Chemistry School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore 637371Singapore institute of Advanced synthesis School of Chemistry and Molecular Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Applied organic Chemistry Department of ChemistryLanzhou UniversityLanzhou 730000China

The seven-membered ring motifs are found in bioactive pharmaceuticals and a wide range of natural products,including alkaloids and terpenoids,which hold significant importance in synthetic chemistry and has garnered considerable attention from both academia and *** the challenges faced in the past decade,the total synthesis of natural products incorporating the non-aromatic cycloheptane skeletons remains a compelling ***,numerous elegant strategies for constructing the sevenmembered ring system have been successfully *** review focuses on the recent advancements in this field from 2017 to April 2023,highlighting key transformations utilized to construct the non-aromatic cycloheptane core structures and serves as a valuable guide for synthetic chemists engaged in the total synthesis of natural products containing seven-membered ring motifs.

关键词： Seven-membered rings Total synthesis Natural products Synthetic strategy Cycloheptane

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Selective N-Methylation of N-Methylaniline with CO_(2) and H_(2) over Cu/In_(2)O_(3) Catalyst

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Chinese Journal of Chemistry 2024年第3期42卷 276-282页

作者： Huan Zheng Bo Qian Lin He State Key Laboratory for Oxo synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouGansu730000 China University of Chinese Academy of Sciences Beijing100049 China

N-Methylation of amines with CO_(2) and H2 is a potential approach for CO_(2) utilization because N-methylated amines can be used as solvents and organic intermediates. In_(2)O_(3)-supported Cu (Cu/In_(2)O_(3)) acts as an effective heterogeneous catalyst for N-methylation reaction of N-methylaniline (MA) with CO_(2) and H_(2),showing higher N,N-dimethylaniline (DMA) selectivity than other supported Cu catalysts. On one hand,the dispersion of Cu can be improved by the defective In_(2)O_(3) support. On the other hand,In_(2)O_(3) support is active in the dissociative adsorption of CO_(2) through C—O bond breaking. In addition,the H_(2) dissociation ability of In_(2)O_(3) can also be enhanced by Cu. The combination of Cu and In_(2)O_(3) is effective in the activation of CO_(2),the adsorption of intermediate N-methylformanilide (MFA),the hydrogenation of MFA to DMA and the prohibition of C—N bond cleavage side reactions,thereby enhancing the reaction rate of MA conversion and the selectivity to DMA.

关键词： N-Methylation CO_(2) Cu/In_(2)O_(3) Supported catalysts Heterogeneous catalysis

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Cyano migration-mediated radical-polar crossover cyclopropanation

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Science China Chemistry 2024年

作者： Ziqiang Wang Yasu Chen Jie Li Chen Zhu Key Laboratory of organic synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials ScienceSoochow University Frontiers Science Center for Transformative Molecules Zhangjiang Institute for Advanced Study and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Shanghai Jiao Tong University

We report a novel cyano migration-mediated radical-polar crossover process, whereby both the sulfonylcyanation of aliphatic alkenes and the formation of cyclopropanes are concurrently achieved. This transformation yields a diverse array of multisubstituted cyclopropanes under mild photocatalytic conditions. Mechanistic studies elucidate that the reaction proceeds via intramolecular nucleophilic substitution, leading to the formation of the cyclopropane derivatives.

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Pentacoordinate Phosphoranes as Versatile Reagents in Fluoroalkylation Reactions

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CCS Chemistry 2024年第1期6卷 165-176页

作者： Huanhuan Song Weihao Li Xiaoying Wang Kaiteng Wang Jingwen Li Shuai Liu Pin Gao Xin-Hua Duan Jinbo Hu Mingyou Hu School of Chemistry Engineering Research Center of Energy Storage Materials and DevicesMinistry of EducationXi’an Key Laboratory of Sustainable Energy Material ChemistryXi’an Jiaotong UniversityXi’an 710049 Key Laboratory of Organofluorine Chemistry Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032

A general method for the synthesis of bench-stable bis(difluoromethyl)pentacoordinate phosphoranes has been *** reaction is rapid,operationally simple,and easily *** pentacoordinate phosphoranes can generate both difluoromethyl radical(·CF_(2)H)and difluorocarbene(:CF_(2))***,a variety of fluoroalkylation transformations havebeen achieved by·CF_(2)H,such asoxidativedifluoromethylation of electron-deficient heterocycles,nickel/photoredox dual-catalyzed difluoromethylation of aryl bromides,and photoredox difluoromethylation of alkenes,or by:CF_(2),such as gem-difluorocyclopropanation of alkenes,base-promoted difluoromethylation of heteroatom nucleophiles,Pd-catalyzed difluoromethylation of arylboronic acids,and Cu-mediated trifluoromethylation of aryl iodides(via:CF_(2) and recombined CF_(3)-).These fluoroalkylation methods have been successfully applied to late-stage fluoroalkylation of drugs and drug-like molecules.

关键词： pentacoordinate phosphorane difluoromethyl radical difluorocarbene difluoromethylation fluoroalkylation

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