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有机化学 ›› 2004, Vol. 24 ›› Issue (5): 554-557. 上一篇    下一篇

研究简报

α-单取代环十二酮构象转换的溶剂效应和温度效应

王明安, 梁晓梅, 韩翔宇, 马祖超, 王道全   

  1. 中国农业大学应用化学系 北京 100094
  • 收稿日期:2003-07-17 修回日期:2003-10-16 接受日期:2003-11-14 发布日期:2022-09-20
  • 基金资助:
    国家自然科学基金(No. 20072053)资助项目

Effects of Solvent and Temperature on the Conformational Interconversion of α-Monosubstituted Cyclododecanones

WANG, Ming-An, LIANG, Xiao-Mei, HAN, Xiang-Yu, MA, Zu-Chao, WANG, Dao-Quan   

  1. Department of Applied Chemistry, China Agricultural University, Beijing 100094
  • Received:2003-07-17 Revised:2003-10-16 Accepted:2003-11-14 Published:2022-09-20
  • Contact: *E-mail: wangdq@cau.edu.cn

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利用1H NMR技术研究了α-单取代环十二酮的α-边外取代[3333]-2-酮构象(A)和α-角顺取代[3333]-2-酮构象(B)相互转换的溶剂效应和温度效应.结果显示,一般情况下随着溶剂极性的增加,构象B的含量增加,这可以解释为构象B较构象A有较大的偶极矩.当分子中的取代基能与羰基形成分子内氢键时,情况则相反,随着溶剂极性的增加,构象B的含量降低,这可以解释为构象B的分子内氢键的减弱.结果还显示,温度的升高有利于两个构象的相互转换而达到新的平衡.

关键词: α-单取代环十二酮, 构象, 构象转换, α-边外取代[3333]-2-酮构象, α-角顺取代[3333]-2-酮构象

The effects of the solvent and temperature on the interconversion between the α-side-exo-substituted[3333]-2-one (A) and α-corner-syn-substituted[3333]-2-one (B) conformations of the α-monosubstituted cyclododecanoneshave been studied by means of 1H NMR technology. The result shows that increasing the polarity of the solvent generally increases the population of the conformation B owing to the higher dipole moment of the conformation B than that of A. By contrast, in the case of the monosubstituted cyclododecanones with an intramolecular hydrogen bondbetween the substituent and the carbonyl group, increasing the polarity of thesolvent decreases the population of the conformation B owing to the weakening of the intramolecular hydrogen bond. The result also shows thatraising temperature is favourable to the interconversion of two conformations,achieving a new equilibrium.

Key words: α-monosubstituted cyclododecanone, conformation, conformational interconversion, α-side-exo-substituted[3333]-2-one conformation, α-corner-syn-substituted[3333]-2-one conformation