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Anodic cyclizations, Seven-Membered Rings, and the Choice of Radical Cation *** Pathways

Chinese Journal of Chemistry 2019年第7期37卷 672-678页

作者： Robert J.Perkins Ruozhu Feng Qingquan Lu Kevin D.Moeller Department of Chemistry Washington University in St.Louis St.Louis MO 63130 USA

While many steps in an oxidative cyclization reaction can be important,it is the cyclization step itself that plays the central *** this step does not proceed well,then optimization of the rest of the sequence is *** report here that the key to the cyclization is channeling the reaction down the correct *** reactions require the use of a radical pathway and some require the use of a radical cation *** example of each is provided along with a strategy for accessing both pathways using a common intermediate.

关键词： Anodic cyclizations Seven-Membered Rings

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Synthesis and in vino Antimalarial Activity of Several Simple Analogues of Peroxyplakoric Acid

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Chinese Journal of Chemistry 2005年第11期23卷 1469-1473页

作者： LIU, He-Hua JIN, Hong-Xia ZHANG, Qi WU, Yi-Kang KIM, Hye-Sook WATAYA, Yusuke State Key Laboratory of Bio-organic and Natural Products Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China Faculty of Pharmaceutical Sciences Okayama University Tsuhima Okayama 700-8530 Japan

Several simple analogues of peroxyplakoric acid were synthesized by using Kobayashi＇s method to construct the key 1,2-dioxane core and tested in vitro for antimalarial activity. The scope and limitation of the method... 详细信息

关键词： peroxides spiroketals cyclizations hemiketals

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Computational Study of the Cyclization of 5-Hexenyl, 3-Oxa-5-Hexenyl and 4-Oxa-5-Hexenyl Radicals

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International Journal of Organic Chemistry 2013年第3期3卷 169-175页

作者： Albert R. Matlin Matthew C. Leyden Department of Chemistry and Biochemistry Oberlin College Oberlin USA

The intramolecular cyclization of 5-hexenyl radicals continues to be an important synthetic method for the construction of five-membered rings. The synthetic utility arises from the high degree of regioselectivity to give predominantly cyclopentyl products in high yield under mild conditions. Recently we reported product cyclization studies on 4-oxa perturbed 5-hexenyl radical. In this paper, we report our results from a computational study (UB3LYP and UCCSD (T)) of the cyclization of a series of 5-hexenyl and 3-and 4-oxa-5-hexenyl radicals. Three highly conserved cyclization tran-sitions states (exo-chair, exo-boat and endo-chair) were located for 10 acyclic radicals. Activation energies were calcu-lated for the three modes of cyclization for each radical. Calculated values for the exo/endo cyclization ratios had a high level of agreement with experiment and predictions were offered for two cases that have not been experimentally tested. The increased percentage of exo-cyclization with 3-and 4-oxa substitution is the result of an increase in the energy dif-ference between the exo-and endo-chair transition states compared to the hydrocarbon systems. The decreased rate of cyclization of the 4-oxa compounds is primarily due to the stabilization of the initial acyclic radical by the vinyl ether linkage. The increase in the rate of cyclization with 3-methyl substitution is due to the increased conformational energy of the starting acyclic radical.

关键词： Radical cyclizations Activation Energies UB3LYP UCCSD (T)

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Gold-Catalyzed Transformastions:Diversity Synthesis and Selectivity

Gold-Catalyzed Transformastions:Diversity Synthesis and Sele...

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中国化学会全国第十一届有机合成化学学术研讨会

作者：刘路张俊良 Shanghai Key Laboratory of Green Chemistry and Chemical Processes Department of Chemsitry East China Normal University

Gold（Ⅰ）-catalysis has received much attention and made much progress in past decade,due to their strong carbophilic Lewis ***,the control of selectivity especially the enatioselectivity of gold catalyzed reaction still poses considerable challenges due to the linear binding *** the past 5 years,we have developed a rich variety of new synthetic methods under the catalysis of gold（Ⅰ）.These reactions aimed at the efficient construction of carbo-and heterocycles,especially furans and pyrroles fused ring systems,featured with the following issues:1)new understanding of the difference between the carbophilic gold catalysts and the oxophilic Lewis catalysts;2)selective synthesis from those substrates with multifunctional groups;3)synthesis of different products from the same starting material（s）by suitable choice of different catalysts;and 4)in-depth investigations of reaction mechanisms and then design of novel cycloaddition or cyclization reactions（Figure 1）.

关键词： Gold catalysis cyclizations Diverse synthesis Selectivity

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