The Synthesis of Rigid Polycyclic Structures for the Study of Diatropic or Steric Effects of a Phenyl Ring on CF Bond
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- 作者：Yung-Yu Chang ; I-Ting Ho ; Tse-Lok Ho ; Wen-Sheng Chung
- 刊名：Journal of Organic Chemistry
- 出版年：2013
- 出版时间：December 20, 2013
- 年：2013
- 卷：78
- 期：24
- 页码：12790-12794
- 全文大小：301K
- 年卷期：v.78,no.24(December 20, 2013)
- ISSN：1520-6904
文摘
Polycyclic compounds 1a鈥?b>c were synthesized to study the diatropic effects of a flanking phenyl ring on nearby CH and CF bonds. 19F NMR spectra of 1b and 1c were strongly deshielded compared with those of the ring-opened compounds 3b, 7b, and 7c. DMol3 calculations on 1a鈥?b>c provided quantitative bond lengths and torsional angles to support the conclusion that the downfield shifts in the 19F NMR spectra are mainly due to steric interactions between the CF bonds and the 蟺 clouds of the phenyl ring(s).