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Science China Chemistry 2023年第6期66卷 1701-1706页

作者： Zhaoming Ma Lantian Sun Jianrong Steve Zhou State Key Laboratory of Chemical Oncogenomics Guangdong Provincial Key Laboratory of Chemical GenomicsSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China Department of Chemistry Hong Kong Baptist UniversityHong KongChina

Enantioselective domino alkenylation-alkynylation of olefins is achieved for the first time,using terminal alkynes directly as pronucleophiles.The new reaction enables facile construction of azacycles carrying quaternary stereocenters,including 5–7 membered pyrrolidines,piperidines and tetrahydroazepines.Moreover,alkynyl groups in azacyclic products provide a useful handle for derivatization that formed both fused and bridged azabicycles.

关键词： membered cycles synthesis

Discovery of gargantulides B and C,new 52-membered macrolactones from Amycolatopsis sp.Complete absolute stereochemistry of the gargantulide family

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Organic Chemistry Frontiers 2022年第2期9卷 462-470页

作者： Daniel Carretero-Molina Francisco Javier Ortiz-López Tetiana Gren Daniel Oves-Costales Jesús Martín Fernando Román-Hurtado Tue Sparholt Jorgensen Mercedes de la Cruz Caridad Díaz Francisca Vicente Kai Blin Fernando Reyes Tilmann Weber Olga Genilloud Fundación MEDINA Centro de Excelencia en Investigación de Medicamentos Innovadores en AndalucíaAvda.del Conocimiento 3418016 ArmillaGranadaSpain The Novo Nordisk Foundation Center for Biosustainability Technical University of DenmarkKemitorvetbuilding 2202800 Kgs.LyngbyDenmark

Gargantulides B and C,two new and highly complex 52-membered glycosylated macrolactones,were isolated from Amycolatopsis sp.strain CA-230715 during an antibacterial screening campaign.The structures of these giant macrolides were elucidated by 2D NMR spectroscopy and shown to be related to gargantulide A,although containing additional β-glucopyranose and/orα-arabinofuranose monosaccharides separately attached to their backbones.Genome sequencing allowed the identification of a strikingly large 216 kbp biosynthetic gene cluster,among the largest type Ⅰ PKS clusters described so far,and the proposal of a previously unreported biosynthetic pathway for gargantulides A-C.The absolute configurations of gargantulides B and C were assigned based on a combination of NMR and bioinformatics analysis of ketoreductase and enoylreductase domains within the multimodular type Ⅰ PKS.In addition,the absolute stereochemistry of gargantulide A has now been revised and completed.Gargantulides B and C display potent antibacterial activity against a set of drug-resistant Gram-positive bacteria and moderate activity against the clinically relevant Gram-negative pathogen Acinetobacter baumannii.

关键词： absolute membered backbone

DFT study on the ruthenium-catalyzed decarbonylative annulation of an alkyne with a six-membered hydroxychromone via C–H/C–C activation

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Organic Chemistry Frontiers 2022年第4期9卷 1056-1064页

作者： Hong-Jing Long Lei Zhang Bing Lian De-Cai Fang College of Chemistry Beijing Normal UniversityBeijing100875P.R.China Tianjin Engineering Technology Center of Chemical Wastewater Source Reduction and Recycling School of ScienceTianjin Chengjian UniversityTianjin300384P.R.China

We report a density functional theory study on the ruthenium-catalyzed decarbonylative annulation of an alkyne with a six-membered hydroxychromone via C–H/C–C activation.The plausible catalytic cycles involve O–H deprotonation,C–H activation,alkyne insertion and formal[3+2]cycloaddition,oxidative insertion and decarbonylation,reductive annulation and the recovery of the catalyst.

关键词： catalyst activation membered

Regio-and stereo-selective olefinic C–H functionalization of aryl alkenes in ethanol

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Organic Chemistry Frontiers 2022年第4期9卷 989-994页

作者： Cong Shen Yuhang Zhu Shuqi Jin Kejie Xu Shuxin Luo Lixia Xu Guofu Zhong Liangjun Zhong Jian Zhang College of Material Chemistry and Chemical EngineeringKey Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of EducationHangzhou Normal UniversityHangzhou311121 ZhejiangPeople’s Republic of China Department of Stomatology The Affiliated Hospital of Hangzhou Normal UniversityHangzhou Normal UniversityHangzhou310015China

We report on N,N-bidentate-chelation-assistedα-and β-olefinic C–H alkenylation of aryl alkenes in ethanol to afford aryl dienes/trienes with excellent regio-and stereo-selectivities.The reaction of 2-alkenyl benzylamine and benzoic acid derived substrates proceeded through six-membered exo-cyclo-metallation and seven-membered endo-cyclometallation.The aerobic protocols feature wide functional-ity tolerance,high selectivities and yields,mild conditions and scalable preparation,and the directing group can be easily removed to afford Boc-protected amine by simple reduction.

关键词： reduction membered stereo

Direct synthesis of N_(2)-unprotected five-memberedcyclic guanidines by regioselective[3+2]annulation of aziridines and cyanamides

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Organic Chemistry Frontiers 2022年第6期9卷 1574-1579页

作者： Chuan-Chuan Wang Xin-Lu Wang Qing-Ling Zhang Juntao Liu Zhi-Wei M Zhi-Jing Liu Ya-Jing Chen School of Pharmaceutical Sciences Key Laboratory of Advanced Drug Preparation TechnologiesMinistry of Education of ChinaCo-Innovation Center of Henan Province for New Drug R&D and Preclinical SafetyZhengzhou University100 Science AvenueZhengzhou 450001HenanChina Faculty of Science Livestock Product Quality Inspection InstituteHenan University of Animal Husbandry and EconomyNo.146 Yingcai StreetZhengzhou 450044HenanChina

A novel and efficient[3+2]annulation of 2-substituted aziridines and N-tosyl cyanamides via a dominoregioselective ring-opening/5-exo-dig cyclization procedure has been developed,allowing the directpreparation of N_(2)-unprotected five-membered cyclic guanidines in good to excellent yields under mildconditions without metals and strong bases.Moreover,the highly biologically interesting urea analoguescould also be conveniently obtained via hydrolysis of the produced guanidines.

关键词： membered protected guanidine

THE ELECTRONIC CONFIGURATION OF 5-membered AND 6-membered RING SANDWICHES

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Chinese Science Bulletin 1982年第10期27卷 1063-1067页

作者：唐敖庆杨忠志冯星洪 Institute of Theoretical Chemistry Jilin University Changchun Shanghai Institute of Organic Chemistry Academia Sinican this paper a method of local symmetry is applied to metallo-organic 5-membered and 6-membered ring poly-decker sandwiches (briefly called 5-membered sandwich Ⅰ and 6-membered sandwich Ⅱ) and the nature of their chemical bond is discussed by means of the HMO theory. The stable electronic configuration for these sandwiches is obtained. A working rule for the total number of valence electrons being 6(2n+l)+4t is proposed. It is reasonable to suggest some potential synthetic goals of poly-decker sandwiches. The discovery in 1951 of the transition metal π-complex ferrocene created a new research field of metalloorganic sandwiches. Since then a lot of bis-decker sandwich-

In this paper, a method of local symmetry is applied to metallo-organic 5-membered and 6-membered ring poly-decker sandwiches (briefly called 5-membered sandwich Ⅰ and 6-membered sandwich Ⅱ), and the nature of their chemical bond is discussed by means of the HMO theory. The stable electronic configuration for these sandwiches is obtained. A working rule for the total number of valence electrons being 6(2n+l)+4t is proposed. It is reasonable to suggest some potential synthetic goals of poly-decker sandwiches. The discovery in 1951 of the transition metal π-complex, ferrocene, created a new research field of metalloorganic sandwiches. Since then, a lot of bis-decker sandwich-

关键词： sandwich membered briefly valence goals created symmetry metallo bonding orbital

RESONANCE ENERGY AND PAULING BOND ORDER OF CONJUGATED HYDROCARBONS CONTAINING A FOUR-membered RING

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Chinese Science Bulletin 1982年第9期27卷 961-965页

作者：杨丕鹏 Department of Chemistry Yunnan University Kunminghere have been a few theoretical calculations of resonance energies (RE) and bond orders of conjugated hydrocarbons containing a four-membered ring. By using the structure-resonance theory Herndon calculated the RE for a wide range of conjugated hydrocarbons. Although the values calculated for a large number of compounds agree with the best SCF-MO results (the Dewar-de Llano RE) there are wide discrepancies in the case of compounds with a four-membered ring and the stabilities

There have been a few theoretical calculations of resonance energies (RE) and bond orders of conjugated hydrocarbons containing a four-membered ring. By using the structure-resonance theory Herndon calculated the RE for a wide range of conjugated hydrocarbons. Although the values calculated for a large number of compounds agree with the best SCF-MO results (the Dewar-de Llano RE), there are wide discrepancies in the case of compounds with a four-membered ring, and the

关键词： conjugated membered hydrocarbons agree moiety bonds orders Pauling substituted pairing

TOTAL SYNTHESIS OF CEMBRENE-C

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Chinese Science Bulletin 1990年第23期35卷 2020-2021页

作者：毛建民李瀛侯自杰李裕林梁晓天 Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000 PRC Institute of Materia Medica Chinese Academy of Medical Sciences Beijing 100050 PRC

Cembrene-C (1), a 14-membered ring diterpene with a special structure, was isolated from some marine sources; 1 has been obtained only in trace amounts through the strong base-catalyzed isomerization of cembrene-A(2).... 详细信息

关键词： membered catalyzed butyl isola

QUANTUM CHEMICAL STUDY ON STRUCTURAL ACIDITY OF HZSM-5 ZEOLITE

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分子催化 1990年第S1期4卷 103-110页

作者： Wu Suochuan Wu Xiangyang (Department of Chemistry, Nanj ing Normal University, Nanjing, China)

The basic units of the framework structure of HZSM-5 zeolite are the five-membered rings which are linked by bridging oxygen atoms and as a result form units of four-membered rings or six membered rings. Semiempirical CNDO/2 quantum chemical method is used to calculate the charge density distribution for all these basic units, i.e., 4-, 5- and 6-membered rings of HZSM-5 zeolite. Quantitative relations between the structural parameter α0 of the acidity of HZSM-5 zeolite and the number of aluminum atoms NAl per unit cell are obtained. Zeolite may be considered as solids acting more or less as protonic polyacids in solution. This protonic acidity is expressed as activity, aH+= [H+]fH+ ,were =nH+aNAl/Zcat and the activity coefficient fH+ is equal to a constant multiplied by the structural parameter, fH+= Kα0, K is taken to be 32. Upder different （SiO2/Al2O3） ratios, therefore, the protonic activities could be obtained theoretically, and the calculation results are

关键词： zeolite membered acidity rings bridging hexane solids terminated constants proton

Structural Origin of the Formation of Odd-Numbered Carbon Clusters from Fullerene Derivatives

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Chinese Physics Letters 2000年第6期17卷 419-421页

作者：孔庆宇庄军赵利王嘉宇钱士雄李郁芬李旭钟超凡蔡瑞芳于勇侯惠奇 State Key Joint Laboratory for Materials ModiScation by Laser Ion and Electron BeamsDepartment of PhysicsFudan UniversityShanghai 200433 Department of Chemistry Fudan UniversityShanghai 200433 Department of Environmental Science and Engineering Fudan UniversityShanghai 200433

We report the mass spectrometric investigation on fullerene derivatives C_(60)CH_(2),C_(60)RH,C_(60)R_(2)(R=C_(6)H_(5)CO-)and C_(60)O_(n)under the 308nm laser ablation.In the negative ion mass spectra of C_(60)CH_(2)C_(60)R_(2),and C_(60)O_(n),odd-numbered clusters C_(57)^(-),C_(55)^(-),C_(53)^(-),C_(51)^(-)are observed clearly in addition to the even-numbered fullerene fragment ions,while for the monoadduct C60RH,odd-numbered species can not be detected.In the positive ion channel,the fragmentation patterns of the three derivatives are similar.A mechanism related to the structural characteristics of the derivatives is supposed for the odd-numbered duster formation.The 3-membered ring formed on the C_(60)cage is thought of to play a vital role for the formation of odd-numbered carbon clusters.

关键词： membered fragmentation addition