論文

2002年4月

5-[4-(1-Hydroxyethyl)phenyl]-10,15,20-triphenylporphyrin as a probe of the transition-state conformation in hydrolase-catalyzed enantioselective transesterifications

Journal of Organic Chemistry
  • Tadashi Ema
  • ,
  • Masahito Jittani
  • ,
  • Kenji Furuie
  • ,
  • Masanori Utaka
  • ,
  • Takashi Sakai

67
7
開始ページ
2144
終了ページ
2151
記述言語
掲載種別
研究論文(学術雑誌)
DOI
10.1021/jo0109063

5-[4-(1-Hydroxyethyl)phenyl]-10,15,20-triphenylporphyrin (1a) and zinc porphyrin 1b were designed and synthesized to experimentally examine the validity of the transition-state model previously proposed for the lipase-catalyzed kinetic resolution of secondary alcohols. The lipases from Pseudomonas cepacia (lipase PS), Candida antarctica (CHIRAZYME L-2), Rhizomucor miehei (CHIRAZYME L-9), and Pseudomonas aeruginosa (lipase LIP) exhibited excellent enantioselectivity (E > 100 at 30 °C). Subtilisin Carlsberg from Bacillus licheniformis (ChiroCLEC-BL) also showed high enantioselectivity for 1a (E = 140 at 30 °C), and the thermodynamic parameters were determined: ΔΔH‡ = -6.8 ± 0.8 kcal mol-1, ΔΔS‡ = -13 ± 3 cal mol-1 K-1. Lipases and subtilisin showed R- and S-preference for 1, respectively. The mechanisms underlying the experimental observations are explained in terms of the transition-state models. The large secondary alcohol 1 is a powerful tool for investigating the conformation of the transition state of the enzyme-catalyzed reactions. The fact that 1 was resolved with high enantioselectivity strongly suggests that the gauche conformation, but not the anti conformation, is taken in the transition state, in agreement with the transition-state models involving the stereoelectronic effect.

リンク情報
DOI
https://doi.org/10.1021/jo0109063
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/11925221
Scopus
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0037023419&origin=inward
Scopus Citedby
https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=0037023419&origin=inward
ID情報
  • DOI : 10.1021/jo0109063
  • ISSN : 0022-3263
  • PubMed ID : 11925221
  • SCOPUS ID : 0037023419

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