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Chinese Chemical Letters 2022年第4期33卷 2031-2035页

作者： Xiaoqian He Kangbao Zhong Dan Heng Zhen Zeng Hao Ni ruopeng bai Yu Lan School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Theoretical and Computational ChemistryChongqing UniversityChongqing 400030China College of Chemistry and Institute of Green Catalysis Zhengzhou UniversityZhengzhou 450001China

The Cu(I)-catalyzed [4 + 1] annulation of vinyl indoles and a carbene precursor is a powerful method for constructing cyclopentaindole derivatives. Density functional theory(DFT) calculations were used to elucidate the mechanism and regioselectivity of this reaction. After Cu-assisted indole C3-alkylation, direct1,5-annulation was favored over the Cu-assisted annulation pathway. Furthermore, the regioselectivity for1,5-annulation was attributed to the generated five-membered-ring product being more stable than the three-membered-ring product from 1,3-annulation, which was the kinetically favored pathway.

关键词： Carbene precursor Regioselectivity DFT calculations Cyclopentaindol C3-alkylation

Geometry, stability and aromaticity of β-diketiminate-coordinated alkaline-earth compounds

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Chinese Chemical Letters 2019年第12期30卷 2249-2253页

作者： Yuanyuan Li Haohua Chen Lingbo Qu ruopeng bai Yu Lan Department of Biological and Chemical Engineering Chongqing University of EducationChongqing 400067China Cooperative Innovation Center of Lipid Resources and Children’s Daily Chemicals Chongqing University of EducationChongqing 400067China School of Chemistry and Chemical Engineering Chongqing UniversityChongqing 401331China College of Chemistry and Molecular Engineering Zhengzhou UniversityZhengzhou 450006China

Alkaline-earth(Ae) metals have attracted a wealth of interdependent research from synthetic chemists.In Ae-catalyzed organometallic reactions,β-diketiminate is a typical ligand used to stabilize Ae catalysts by forming six-membered rings comprising Ae metals.Herein,studies focusing on the configuration of β-diketiminate-coordinated Ae compounds observed that the C-C and C-N bonds are homogeneous and unchanged.Furthermore,energetic studies observed that the formation of the Ae-incorporated sixmembered rings results in enhanced stability of>20 kcal/mol.The nucleus-independent chemical shifts,anisotropy of the induced current density,and molecular orbital analyses demonstrated the nonaromaticity of the β-diketiminate-coordinated Ae compounds.The improved stability of these compounds can be explained by the delocalization of the π electrons derived from the β-diketiminate moiety.

关键词： β-Diketiminate-coordinated Alkaline-earth compounds Theoretical study Aromaticity Stability

Theoretical prediction on the reactivity of the Co-mediated intramolecular Pauson-Khand reaction for constructing bicyclo-skeletons in natural products

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Chinese Chemical Letters 2019年第4期30卷 889-894页

作者： Lei Zhu Zheyuan Wang Song Liu Tao Zhang Zhen Yang ruopeng bai Yu Lan School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Theoretical and Computational Chemistry Chongqing University Laboratory of Chemical Genomics School of Chemical Biology and Biotechnology Peking University Shenzhen Graduate School College of Chemistry and Molecular Engineering Zhengzhou University

The Co_2(CO)_8-mediated intramolecular Pauson-Khand reaction is an efficient approach for constructing polycyclic skeletons. Recently, some of us reported a series of this type reactions involving stericallyhindered enynes for synthesizing natural products with reasonable reaction rates and yields. However,the reason for the high reactivity of the reaction remains unclear. We employed density functional theory calculations to clarify the mechanism and reactivity for this reaction. In contrast with chain olefin reactants, CO insertion is considered to be the rate-determining step for the overall Pauson-Khand reaction of cyclooctene derivatives. The reduced activation free energy for the alkene insertion step is attributed to: i) the electron-withdrawing group in close proximity to the C—C triple bond enhancing the reactivity of the alkyne moiety; ii) lower steric hindrance during alkene insertion when using the cyclooctene derivative. The effect of the substituent on the Co_2(CO)_8-mediated intramolecular PausonKhand reaction was then investigated. Internal alkenes exhibit lower reactivity than terminal alkenes because of the steric hindrance introduced by the substituted group. The cis internal alkene exhibits higher reactivity than the trans internal alkene. An ester group in close proximity to the C—C triple bond significantly enhances the reactivity.

关键词： Pauson-Khand reaction Bicyclo-skeletons DFT calculations Mechanism Reactivity

Theoretical insight into phosphoric acid-catalyzed asymmetric conjugate addition of indolizines to a,β-unsaturated ketones

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Chinese Chemical Letters 2018年第8期29卷 1237-1241页

作者： Haohua Chen Lei Zhu Kangbao Zhong Xiaoyu Yue Ling-Bo Qu ruopeng bai Yu Lan School of Chemistry and Chemical Engineering Chongqing University College of Chemistry and Molecular Engineering Zhengzhou University

Phosphoric acid catalysis is a powerful tool for the construction of new CààC bonds because of its unique LUMO-lowering activity. Theoretical calculations were employed to investigate phosphoric acidcatalyzed asymmetric conjugate addition of indolizines to a,b-unsaturated ketones. The calculation results showed that this transformation proceeds via a reaction pathway involving nucleophilic addition,deprotonation–aromatization, and tautomerization. The computational results showed that deprotonation–aromatization is the rate-determining step and the enantioselectivity-determining step.The S-configured product was preferentially generated via a pathway starting from the s-cis conjugated ketone, whereas the s-trans isomer led to a side product with the R configuration. Non-covalent interaction analysis showed that the enantioselectivity is mainly caused by bond-rotation strain in the transition states of the deprotonation–aromatization step.

关键词： Phosphoric acid catalysis Theoretical calculations Mechanism Enantioselectivity

Oxidative cyclopalladation triggers the hydroalkylation of alkynes

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Chinese Chemical Letters 2023年第10期34卷 146-152页

作者： Kangbao Zhong Shihan Liu Xiaoqian He Hao Ni Wei Lai Wenting Gong Chunhui Shan Zhuang Zhao Yu Lan ruopeng bai School of Chemistry and Chemical Engineering Chongqing Key Laboratory of Theoretical and Computational ChemistryChongqing UniversityChongqing 400030China College of Chemistry and Institute of Green CatalysisZhengzhou UniversityZhengzhou 450001China College of Chemistry Chongqing Normal UniversityChongqing 401331China

This report describes the oxidative cyclopalladation activation of a C≡C bond during the Pd-catalyzed hydroalkylation of alkynes and analyzes potential reaction pathways based on density functional theory calculations. The more favorable pathway in-volves an oxidative cyclopalladation to generate a palladacyclopropene intermediate, which is rarely examined in Pd-catalyzed alkyne transformations. The reaction pathway proposed herein is kinetically favorable relative to the commonly proposed alkyne insertion mode. Furthermore, the Laplacians of the electron density, interaction region indicators, Mayer bond orders, and localized orbital bonding are evaluated to determine the reaction processes and characterize the key intermediates. Theoretical calculations indicate covalent bonding between a Pd(II) center and the two C-atoms in three-membered palladacycle species. Finally, electrostatic potential analysis reveals that the regioselectivity is governed by the charge distribution on the palladacycle moiety during the protonation step.

关键词： Pd catalysis Alkynes activation Hydrazones activation Oxidation state DFT

On the Mechanism of Transition-Metal Catalyzed Carbene Transformations: A Theoretical View

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On the Mechanism of Transition-Metal Catalyzed Carbene Trans...

On the Mechanism of Transition-Metal Catalyzed Carbene Transformations: A Theoretical View

中国化学会·第十三届全国物理有机化学学术会议

作者： Yu Lan Chunhui Shan ruopeng bai College of Chemistry Zhengzhou University School of Chemistry and Chemical Engineering Chongqing University

It is a long history since carbene was reported as an active intermediate in syntheticorganic chemistry. Carbene species often involve a 6e carbon atom,which reveals unique chemical character and can be employed for t...

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On the Mechanism of Transition-Metal Catalyzed Carbene Trans...

Use of induced pluripotent stem cell-derived brain cells,organoids,assembloids,and blood-brain barrier models in understanding alcohol and anesthetic-induced brain injuries:an emerging perspective

2019中国化学会第十五届全国计算（机）化学学术会议

作者：蓝宇 Chunhui Shan Donghui ruopeng bai 重庆大学 School of Chemistry and Chemical Engineering Chongqing University College of Chemistry Zhengzhou University

Carbene species often include a 6e carbon atom, which reveals unique chemical character and can be an ideal choice for the construction of various C-X (X = C, H, N, O, S, P, etc.) bonds. 1 Noteworthy, the introduction of transition metals makes carbene chemistry more diverse and energetic, while understanding for the detailed mechanism and unexpected chemoselectivity of carbene-related reactions becomes more difficult and challenging in both experiment and theory. During the past decade, our group focused on the mechanistic study for the transition-metalcatalyzed carbene transformation reactions.

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Neural Regeneration Research 2024年第5期19卷 953-954页

作者： Xiaowen bai Department of Cell Biology Neurobiology&AnatomyMedical College of WisconsinMilwaukeeWIUSA

Neurological disorders,including developmental disorders,Alzheimer’s disease(AD),and psychiatric conditions,have significant social and economic impacts globally.Despite extensive research into the underlying mechanisms of these disorders,effective treatments remain elusive,partly due to the complexity of the brain,the limited availability of human brain tissue,and the blood-brain barrier(BBB)’s impermeability to certain drugs.This perspective article discusses the potential of human induced pluripotent stem cell(iPSC)-based models of brain cells,organoids,assembloids,and BBB to advance our understanding of the etiology,progression,and mechanisms of brain injuries induced by alcohol consumption and general anesthesia.These models could also be used to develop protective and therapeutic approaches.

关键词： injuries protective drugs

Variations of sediment organic phosphorus and organic carbon during the outbreak and decline of algal blooms in Lake Taihu,China

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Journal of Environmental Sciences 2024年第5期139卷 34-45页

作者： Jiehua Wang Xiuling bai Wenchao Li Pingping Zhang Mengdi Zhang Haoran Wang Yingge bai College of Geography and Environmental Science Henan UniversityKaifeng 475004China Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions(Henan University) Ministry of EducationKaifeng 475004China National Demonstration Center for Environment and Planning Henan UniversityKaifeng 475004China Surrey International Institute Dongbei University of Finance and EconomicsDalian 116000China

In this study,sediment organic phosphorus(OP)and organic carbon(OC)in Lake Taihu,China,as well as their relationships,were analyzed during the outbreak and decline of algal blooms(ABs)over a five-month field study.The results showed synchronous temporal changes in the sediment OP and OC contents with the development of ABs.In addition,there was a significant positive correlation between the sediment OP and OC(p<0.01),suggesting simultaneous deposition and consumption during the ABs outbreak.The sediment OP and OC contents decreased significantly at the early and last stages of the ABs outbreak and increased at the peak of the ABs outbreak and during the ABs decline.These temporal variation patterns suggest that the sediment OC and OP contents did not consistently increase during the ABs outbreak,even though algae are an important source of organic matter in sediments.The depletion or enrichment of OC and OP in sediments may also depend on the scale of the ABs outbreak.The obtained results revealed significant differences in the sediment OC and OP contents between the months(p<0.05).In addition,OP in the sediments was dominated by orthophosphate diester(phospholipids and DNA-P)and orthophosphate monoester during the ABs outbreak and decline,respectively.The active OC contents and proportions in the sediments in the ABs outbreak were significantly lower than those observed in the ABs decline period,demonstrating the significant impacts of the ABs outbreak and decline on the sediment OC and OP in Lake Taihu.

关键词： Algal blooms Organic phosphorus Organic carbon Sediment ^(31)P NMR Lake Taihu

取代基电性效应对碳硅还原消除区域选择性调控的理论研究

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有机化学 2023年第10期43卷 3608-3613页

作者：彭菊何晓倩廖黎丽白若鹏蓝宇重庆大学化学化工学院理论与计算化学重庆市重点实验室重庆401331 郑州大学化学学院绿色催化中心郑州450001

有机反应区域选择性的调控是有机化学的重要研究内容之一,而电性效应则是其重要调控因素.运用密度泛函理论计算,以钯催化2-碘联苯化合物与硅杂环丁烷的环化反应为模板,研究了取代基电性效应在还原消除过程中对区域选择性的影响,并给出... 详细信息

有机反应区域选择性的调控是有机化学的重要研究内容之一,而电性效应则是其重要调控因素.运用密度泛函理论计算,以钯催化2-碘联苯化合物与硅杂环丁烷的环化反应为模板,研究了取代基电性效应在还原消除过程中对区域选择性的影响,并给出了该反应的详细反应机理.计算结果表明,该反应经历了Pd—I键氧化加成、协同金属去质子、Pd—Si键氧化加成、还原消除过程得到硅杂八元环产物,且C—Si键还原消除是反应的速率决定步骤.对Pd(IV)还原消除过渡态中电子效应的研究证明,当使用不对称2-碘联苯作为反应底物时,芳环电子密度是区域选择性的主要控制因素,电子密度更高的基团更容易发生还原消除,与该基元反应电子流向一致.

关键词：电性效应区域选择性还原消除密度泛函理论