高等学校化学学报

高等学校化学学报 ›› 2009, Vol. 30 ›› Issue (11(1)): 58.

• 研究论文 • 上一篇    下一篇

2-苄基-2-乙氧羰基环戊烷氧离子差向异构化的密度泛函研究

冯华升, 田宇, 孙竹芳, 王文军, 胡志彪, 谢伦嘉   

  1. 北京化工研究院基础研究部, 北京 100013
  • 收稿日期:2009-07-28 出版日期:2009-11-30 发布日期:2009-11-30
  • 通讯作者: 谢伦嘉, 男, 教授, 主要从事有机合成, 介孔材料应用和石油化工相关研究. E-mail: xielunjia@brici.ac.cn

Density Functional Theory Study for Epimerization of 2-Benzyl-2-ethoxycarbonyl-cyclopentanolate Ion

FENG Hua-Sheng, TIAN Yu, Sun Zhu-Fang, WANG Wen-Jun, HU Zhi-Biao, XIE Lun-Jia*   

  1. Fundamental Research Department, Beijing Research Institute of Chemical Industry, Beijing 100013, China
  • Received:2009-07-28 Online:2009-11-30 Published:2009-11-30
  • Contact: XIE Lun-Jia. E-mail: xielunjia@brici.ac.cn

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摘要：

在B3LYP/6-311+G(d,p)水平计算了2-苄基-2-乙氧羰基环戊醇顺反异构体和在强碱性条件下脱去醇羟基上的氢后形成的相应负离子的构象及能量. 计算结果表明, 2-苄基-2-乙氧羰基环戊烷氧负离子的稳定构象为环戊环开环, 一端形成醛基, 另一端形成碳负离子与酯羰基共同构成的共轭负电中心. 其中, 醛基与酯羰基形成的反式构象的负离子能量比顺式构象的负离子能量低757 kJ/mol, 而构象翻转的活化能仅为305 kJ/mol, 说明构象翻转为热力学控制的反应, 顺式构象即能够自发翻转呈反式构象, 解释了在Williamson醚合成反应中顺、反构型翻转的现象.

关键词: 2-苄基-2-烷氧羰基环戊醇; 差向异构化; Williamson醚合成; 密度泛函理论

Abstract:

DFT studies were carried out in order to investigate the epimerization of 2-benzyl-2-ethyoxyl-carbonyl-cyclopentanol in etherified reaction. Stationary structures and energy were obtained at the B3LYP/6-311+G(d,p) level. The loop will open when 2-benzyl-2-ethoxycarbonyl-cyclopentanol lose a H+, the —C—O- group will turn into a aldehyde group, and the other carbon atom and the carbonyl composite a conjugate negative center. The energy of the trans conformation of the anion is 757 kJ/mol lower than the cis conformation, and the energy barrier of the conformation invert is only 305 kJ/mol. It shows the conformation invert reaction is controlled by thermodynamics and will happen easily. The result can explain the epimerization of 2-benzyl-2-ethoxycarbonyl-cyclopentanol in Williamson ether synthesis.

Key words: 2-Benzyl-2-ethoxycarbonyl-cyclopentanol; Epimerization; Williamson ether synthesis; Density functional theory(DFT)

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