Synthesis of enantiopure aliphatic acetylene alcohols and determination of their absolute configurations by 1H NMR anisotropy and/or X-ray crystallography

Satoshi Sekiguchi, Megumi Akagi, Junpei Naito, Yoko Yamamoto, Hiromi Taji, Shunsuke Kuwahara, Masataka Watanabe, Yoshiki Ozawa, Koshiro Toriumi, Nobuyuki Harada

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

The MαNP acid method has been applied to racemic aliphatic acetylene alcohols in order to simultaneously prepare enantiopure alcohols and to determine their absolute configurations by 1H NMR anisotropy. Racemic acetylene alcohols 6-8, 11, and 20 were esterified with MαNP acid (S)-(+)-1 to yield diastereomericMαNP esters which were efficiently separated by HPLC on silica gel with separation factors α in the range 1.60-1.93. The 1H NMR anisotropy factors Δδ [= δ(2nd fr.) - δ(1st fr.)] were calculated from the data of the first- (22a-27a) and second-eluted MαNP esters (22b-27b). The absolute configurations of the first-eluted esters were determined from the distribution of Δδ values in the MαNP sector rule. In the case of MαNP ester 26b, the assigned absolute configuration was confirmed by X-ray crystallography. The solvolysis of MαNP esters yielded enantiopure acetylene alcohols 5-8 with established absolute configurations.

Original languageEnglish
Pages (from-to)2313-2324
Number of pages12
JournalEuropean Journal of Organic Chemistry
Issue number13
DOIs
Publication statusPublished - 2008 May
Externally publishedYes

Keywords

  • Absolute configuration
  • Acetylene alcohols
  • Configuration determination
  • MαNP esters
  • NMR anisotropy
  • X-ray diffraction

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry

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