論文

査読有り
2004年6月22日

Sequential arrangement of γ-vaierolactone enantiomers enclathrated in cholic acid channels as studied by 13C solid-state NMR: Elucidation of the optical resolution mechanism

Journal of the American Chemical Society
  • Shinji Nakamura
  • ,
  • F. Imashiro
  • ,
  • K. Takegoshi
  • ,
  • Takehiko Terao

126
28
開始ページ
8769
終了ページ
8776
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1021/ja049463l

The mechanism of the optical resolution of γ-valerolactone (VAL) enantiomers by enclathration in cholic acid (CA) channels was investigated. 13C cross-polarization magic-angle spinning spectra of CA/ VAL inclusion compounds show four methyl 13C peaks of VAL with different intensities depending on the enantiomeric ratios. The four peaks were assigned to the inner and end (S)-(-)-enantiomers (S) in the S domain and the inner and end (R)-(+)-enantiomers (R). The relative intensities of the four methyl 13C peaks cannot be explained by the random process model for inclusion but are successfully reproduced by assuming the first-order Markov process, in which the inclusion probabilities of S and R depend on which enantiomer has precedingly entered the CA channel. The probability p S/S that two S enantiomers successively enter a channel is thus found to be 83%, and pR/R is 50%. The large probability of pS/S indicates that once an S enantiomer enters a channel, it become easy for other S enantiomers to successively enter the channel, and thus the large enantiomeric excess of S is obtained. The inclusion probabilities of S and R were confirmed by 1D 13C-13C polarization-transfer experiments among the four methyl carbons of VAL in the CA channel. Further, we found that the 13C line widths and peak positions of the CA tail group change depending on the enantiomeric ratio. We concluded that once S is included, it changes the conformation of the CA tail group so that other S enantiomers become easy to successively enter the channel.

リンク情報
DOI
https://doi.org/10.1021/ja049463l
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/15250730
ID情報
  • DOI : 10.1021/ja049463l
  • ISSN : 0002-7863
  • PubMed ID : 15250730
  • SCOPUS ID : 3242691279

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