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Spin effect on redox acceleration and regioselectivity in Fe-catalyzed alkyne hydrosilylation

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national Science Review 2024年第2期11卷 155-167页

作者： Peng He Meng-Yang Hu Jin-Hong Li Tian-Zhang Qiao Yi-Lin Lu Shou-Fei Zhu Frontiers Science Center for New organic Matter State Key Laboratory and Institute of Elemento-Organic Chemistry Nankai University

Iron catalysts are ideal transition metal catalysts because of the Earths abundant, cheap, biocompatible features of iron salts. Iron catalysts often have unique open-shell structures that easily undergo spin crossover in chemical transformations, a feature rarely found in noble metal catalysts. Unfortunately, little is known currently about how the open-shell structure and spin crossover affect the reactivity and selectivity of iron catalysts, which makes the development of iron catalysts a low efficient trial-and-error program. In this paper, a combination of experiments and theoretical calculations revealed that the iron-catalyzed hydrosilylation of alkynes is typical spin-crossover catalysis. Deep insight into the electronic structures of a set of well-defined open-shell active formal Fe(0) catalysts revealed that the spin-delocalization between the iron center and the 1,10-phenanthroline ligand effectively regulates the iron center's spin and oxidation state to meet the opposite electrostatic requirements of oxidative addition and reductive elimination, respectively,and the spin crossover is essential for this electron transfer process. The triplet transition state was essential for achieving high regioselectivity through tuning the nonbonding interactions. These findings provide an important reference for understanding the effect of catalyst spin state on reaction. It is inspiring for the development of iron catalysts and other Earth-abundant metal catalysts, especially from the point of view of ligand development.

关键词： spin effect spin-delocalization spin crossover iron-catalysis alkyne hydrosilylation

Organo-electroreduction enables arylcarboxylation of styrenes

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Science China chemistry 2024年第11期67卷 3825-3832页

作者： Yanwei Wang Qian Wang Zile Zhu Weikang Qi Youai Qiu State Key Laboratory and institute of Elemento-organic chemistry Frontiers Science Center for New Organic Matter Haihe Laboratory of Sustainable Chemical Transformations College of Chemistry Nankai University

Electroreduction offers an alternative to generate high active intermediates from electrophiles(halides, alkenes, etc.) in organic synthesis. However, it still remains challenge to enable the transformations in controlled fashion for substrates with similar reduction potentials. Herein, an electroreductive arylcarboxylation of styrenes with aryl halides and CO2promoted by an organomediator has been developed. The reaction exhibits the remarkable reactivity control between styrenes and aryl halides bearing very similar reduction potentials, which is enabled by the addition of a simple organic mediator. The mediated process for different kinds of aryl halides(iodides and bromides) could be achieved by simply tuning the electronic effect of the skeleton of naphthalene. This protocol displays a broad substrate scope and the extension to late-stage modification of biorelevant molecules and their derivatives showed a bright prospect. Moreover, density functional theory(DFT) calculations and mechanistic studies have been conducted and provide solid support to rationalize the selectivity and reactivity control observed.

关键词： CO2 utilization reductive organo-mediator carboxylation electroreduction aryl halides

Copper-catalyzed asymmetric dearomatizing amination of 2-naphthols:Csp^(2)–N coupling via 1,3-reductive elimination

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Science China chemistry 2024年第8期67卷 2694-2700页

作者： Aying Yihuo Maoping Pu Zheng Tan Jibang Liao Jiuqi Tan Qi-Lin Zhou Xiaohua Liu Xiaoming Feng Key Laboratory of Green chemistry&Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengdu 610064China Key Laboratory and institute of Elemento-organic chemistry College of Chemistry Frontiers Science Centerfor New Organic MatterNankai UniversityTianjin300071China

An efficient catalytic asymmetric dearomatizing amination of 2-naphthols and phenols catalyzed by N,N′-dioxide-copper(I)complex as a chiral catalyst was presented.A variety of optically activeβ-naphthalenone compounds with a nitrogen-containing quaternary carbon stereocenter were obtained with high yield and enantioselectivity under mild reaction *** studies indicated that this Csp^(2)–N dearomatizing coupling proceeds via 1,3-reductive elimination of phenolate-Cu~Ⅲ-amino intermediate in five-membered ring transition *** origin of enantioselectivity has also been elucidated based on density functional theory calculations.

关键词： asymmetric catalysis amination dearomatization copper catalysis coupling reaction

Cobalt(Ⅲ)hydride HAT mediated enantioselective intramolecular hydroamination access to chiral pyrrolidines

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Science China chemistry 2024年第6期67卷 2002-2008页

作者： Qi Meng Tao Qin Huanran Miao Ge Zhang Qian Zhang Jilin Province Key Laboratory of organic Functional Molecular Design&Synthesis Department of ChemistryNortheast Normal UniversityChangchun130024China State Key Laboratory of Organometallic chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai200032China

Enantioenriched pyrrolidines and derivatives are ubiquitous substructures in compounds of importance to medicinal and biological ***,we report an efficient cobalt-catalyzed intramolecular asymmetric hydroamination reaction that produces chiral pyrrolidines with good to excellent yield and *** with previously reported radicalinvolved methodologies for enantioenriched pyrrolidines,these conditions feature two elegant versatilities,enabling(1)the use of cobalt-catalyzed hydrogen atom transfer(HAT)to generate organocobalt intermediates that bring radical reaction to organometallic chemistry,and(2)enantioselective intramolecular C-N bond forging through an S_(N)2-like displacement involving dynamic kinetic resolution(DKR).This approach provides a new alternative and efficient methodology for enantioselective radical-involved C-N bond construction that can be used in the synthesis of both chiral pyrrolidines and homologous nitrogen heterocycles.

关键词： asymmetric catalysis radical hydroamination cobalt catalysis hydrogen atom transfer

Dielectric Constant Calculation of Poly(vinylidene fluoride)Based on Finite Field and Density Functional Theory

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Chinese Journal of Polymer Science 2024年第5期42卷 655-662,I0009页

作者： Yong-Zhi Lin Lu-Kun Feng Ya-Dong Li Chao-Fan Chang Cai-Zhen Zhu Ming-Liang Wang Jian Xu College of chemistry and Environmental Engineering Shenzhen UniversityShenzhen518055China Chengdu institute of organic chemistry Chinese Academy of SciencesChengdu610041China

In this study,we proposed a novel method that integrates density functional theory(DFT)with the finite field method to accurately estimate the polarizability and dielectric constant of *** approach effectively accounts for the influence of electronic and geometric conformation changed on the dielectric *** validated our method using polyethylene(PE)and polytetrafluoroethylene(PTFE)as benchmark materials,and found that it reliably predicted their dielectric ***,we explored the impact of conformation variations in poly(vinylidene fluoride)(PVDF)on its dielectric constant and *** resulting dielectric constants ofα-andγ-PVDF(3.0)showed excellent agreement with crystalline PVDF in *** findings illuminate the relationship between PVDF’s structural properties and its electrical behavior,offering valuable insights for material design and applications.

关键词： Dielectric constant PVDF Finite field DFT

Asymmetric side-chain engineering of organic semiconductor for ultrasensitive gas sensing

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Chinese Chemical Letters 2024年第3期35卷 428-433页

作者： Xiaoying Ma Xiaojuan Dai Lanyi Xiang Jiajun Chang Danfeng Zhi Haozhen Zhao Zhenjie Ni Ye Zou Xike Gao Fengjiao Zhang School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China Laboratory of organic Solids Institute of ChemistryChinese Academy of SciencesBeijing 100190China Key Laboratory of Synthetic and Self-Assembly chemistry for organic Functional Molecules Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China Binzhou institute of Technology Binzhou 256606China

Molecular structure of organic semiconductor plays a critical role in determining the performance and functionality of organic electronic devices,by optimizing the electrical,optical and physicochemical *** alkyl chains are fundamental units in tailering the solubility and assemblability,among which the asymmetric properties have been reported as key element for controlling the packing motifs and intrinsic charge ***,we expanded the scope of molecular asymmetry dependent sensing features based on a new series of naphthalene diimides(NDI)-based derivatives substituted with a same branching alkyl chain but various linear-shaped alkyl chains(Cn-).A clear molecular stacking change,from head-to-head bilayer to head-to-tail monolayer packing model,is observed based on the features of anisotropic molecular interactions with the change in the chain *** importantly,a unique LUMO level shift of 0.17 eV is validated for NDI-PhC4,providing a record sensitivity up to 150%to 0.01 ppb ammonia,due to the desired molecular reactivity and device amplification *** results indicate that asymmetric side-chain engineering opens a route for breath healthcare.

关键词： organic thin film transistor Asymmetric side chain Gas sensing Molecular stacking Energy level manipulating

Iridium-Catalyzed Asymmetric Hydrogenation of Dialkyl Imines

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CCS chemistry 2024年第4期6卷 905-911页

作者： Zheng Wang Xin-Yi Yang Yue Xu Qi-Lin Zhou State Key Laboratory and institute of Elemento-organic chemistry College of ChemistryFrontiers Science Center for New Organic MatterNankai UniversityTianjin 300071

Asymmetric hydrogenation of dialkyl imines to chiral amines is difficult because the two alkyls of imines are so similar in spatial and electronic structure that chiral catalysts are difficult to distinguish between *** this study,we described an asymmetric hydrogenation of dialkyl imines by a chiral iridium catalyst containing spiro phosphine-amine-phosphine *** precisely adjusting the chiral pocket of catalyst,a highly efficient catalyst was *** this catalyst,a variety of dialkyl imines were hydrogenated to chiral amines with high yield and enantioselectivity.

关键词： spiro PNP ligand iridium catalyst enantioselective hydrogenation dialkyl imines chiral amines

Chlorajaponins A—Q,Lindenane-Related Sesquiterpenoid Dimers from Chloranthus japonicus and Their Biological Activities

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Chinese Journal of chemistry 2024年第11期42卷 1247-1259页

作者： Wei-Jiao Feng Yue Gu Pei-Zhi Huang Hong-Ying Yang Rui Zhang Yi-Lin He Ting-Hong Lv Ya Li Kun Gao State Key Laboratory of applied organic chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhouGansu730000 China Research institute Lanzhou Jiaotong UniversityLanzhouGansu730070 China

Seventeen undescribed lindenane-related sesquiterpenoid dimers,chlorajaponins A—Q(1—17),and 13 reported analogs(18—30)were isolated from Chloranthus japonicus *** 1 possesses an unprecedented 3/5/7/5/5/6/5/3 fused octacyclic scaffold,featuring a 6(5→4)-abeo-lindenane monomer,while 2 exhibits a 3/5/6/6/5/6/5/3 fused octacyclic *** structures were determined through a combination of spectroscopic analyses and X-ray *** 1,2,and 18 demonstrated significant inhibitory effects on lipid accumulation and effectively reduced the levels of triglycerides and total cholesterol,as well as the levels of aspartate aminotransferase and alanine aminotransferase in a HepG2 cell *** addition,compounds 1,2,and 18 significantly suppressed the protein expression of the fatty acid synthase(FASN)and the sterol regulatory element-binding protein 1(SREBP1).Moreover,the anti-inflammatory assay showed that compounds 19—22 and 25 inhibited the NO production induced by lipopolysaccharide in RAW 264.7 macrophages with IC50 values of 7.89±0.44,6.25±0.46,2.98±0.29,10.77±0.60,and 3.60±0.28μmol/L.

关键词： Chloranthus japonicus Lindenane-type sesquiterpenoid dimers Lipid-lowering activity Anti-inflammatory activity NMR spectroscopy Natural products X-ray diffraction

Photocatalyzed ditrifluoromethylthiolation of alkenes with CF_(3)SO_(2)Na

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Science China chemistry 2024年第2期67卷 587-594页

作者： Fangming Chen Lvqi Jiang Chunyang Hu Jie Liu Wenbin Yi School of chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing210094China Key Laboratory of Organofluorine chemistry Shanghai Institute Organic ChemistryChinese Academy of SciencesShanghai200032China

Since the first report of sodium trifluoromethanesulfinate(CF_(3)SO_(2)Na) as an electrophilic trifluoromethylthiolation reagent in 2015,there has been no breakthrough in research in this ***,we disclose an unprecedented usage of CF_(3)SO_(2)Na as a radical trifluoromethylthiolation reagent.A photocatalyzed ditrifluoromethylthiolation of alkenes with CF_(3)SO_(2)Na in the presence of PPh_(3) and catalytic copper has been ***,either Ir[(p-Fppy)_(2)(bpy)]PF_6 or Ir(ppy)_(3) could facilitate this *** studies indicate that initiation of the radical chain proceeded via two different photocatalytic quenching *** protocol provides a practical method for the construction of diverse vicinal ditrifluoromethylthiolated compounds.

关键词： trifluoromethylthiolation photocatalysis radical difunctionalization alkenes