Mechanisms of circumambulatory rearrangements of 5-halogeno-1,2,3,4,5-pentamethoxycarbonylcyclopentadienes

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• 作者：G. A. Dushenko ; I. E. Mikhailov ; O. I. Mikhailova…
• 关键词：Key wordshalocyclopentadienes ; fluoro ; chloro ; bromo ; and iodopentamethoxycarbonylcyclopentadienes ; rearrangements ; density functional theory
• 刊名：Russian Chemical Bulletin
• 出版年：2015
• 出版时间：September 2015
• 年：2015
• 卷：64
• 期：9
• 页码：2043-2049
• 全文大小：612 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Chemistry
  Organic Chemistry
  Inorganic Chemistry
  Russian Library of Science
  
• 出版者：Springer New York
• ISSN：1573-9171
• 卷排序：64

文摘

Possible paths of halogen atom migration in 5-halogeno-1,2,3,4,5-pentamethoxycarbonylcyclopentadienes were studied using the density functional theory. The calculations revealed preferential 1,5(in comparison with 1,3-) sigmatropic shifts of halogen atoms along the perimeter of the five-membered ring with the energy barriers ΔE_ZPE≠ = 42.9, 26.9, 19.8, and 15.4 kcal mol–1 for the fluoro-, chloro-, bromo-, and iodosubstituted derivatives, respectively. The calculated charges of halogen atoms in the structures of transition states for 1,5-shifts change from negative for the fluorine atom to positive for the iodine atom (–0.356 (F), 0.019 (Cl), 0.052 (Br), 0.184 e (I)). The migration capacity increases in the order F < Cl < Br < I with an increase in the atomic radius of halogen.