Synthesis, Resolution, and VCD Analysis of an Enantiopure Diazaoxatricornan Derivative
详细信息 查看全文
- 作者：Pierre Mobian ; Cyril Nicolas ; Eric Francotte ; Thomas Bü ; rgi ; Jé ; rô ; me Lacour
- 刊名：Journal of the American Chemical Society
- 出版年：2008
- 出版时间：May 21, 2008
- 年：2008
- 卷：130
- 期：20
- 页码：6507 - 6514
- 全文大小：1338K
- 年卷期：v.130,no.20(May 21, 2008)
- ISSN：1520-5126
文摘
Using simple organic synthetic transformations, a novel diazaoxatricornan derivative, the 12c-methyl-12-phenyl-8-propyl-12,12c-dihydro-8H-4-oxa-8,12-diazadibenzo[cd,mn]pyrene (6a), was prepared. This novel chiral cup-shaped molecule was isolated in racemic form and in excellent yield after the addition of methyl lithium to the BF4 salt of a novel unsymmetrical diazaoxatriangulenium cation. Compound 6a was found to be stable under classical laboratory conditions—something not obvious considering the extreme stability of the carbenium ion precursor, the electron-rich nature of the core, and the strain induced by the pyramidalization of the central carbon. The enantiomers were readily separated by chiral stationary phase chromatography, and the absolute configuration of (−)-(S)-6a was determined by a comparison of the experimental and theoretical vibrational circular dichroism (VCD) spectra. This isolation of (−)-(S)-6a and (+)-(R)-6a constitutes thus the first report of a nonracemic closed-capped chiral bowl molecule for which the chirality is due to the intrinsic dissymmetry of the central core of the structure only.