高等学校化学学报

高等学校化学学报 ›› 1998, Vol. 19 ›› Issue (S1): 142.

• Organic Synthesis Chemistry • 上一篇    下一篇

A Novel Cyclization of Squalene Initiated by Radical Cation

Wei Wang1, Qing-Xiang Guo2, Wei Yu1, You-Cheng Liu1,2   

  1. 1. National Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou 730000;
    2. Department of Chemistry, University of Science and Technology of China, Hefei 230026
  • 出版日期:1998-12-31 发布日期:1998-12-31
  • 基金资助:
    Support from the National Natural Science Foundation of China is gratefully acknowledged

A Novel Cyclization of Squalene Initiated by Radical Cation

Wei Wang1, Qing-Xiang Guo2, Wei Yu1, You-Cheng Liu1,2   

  1. 1. National Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou 730000;
    2. Department of Chemistry, University of Science and Technology of China, Hefei 230026
  • Online:1998-12-31 Published:1998-12-31
  • Supported by:
    Support from the National Natural Science Foundation of China is gratefully acknowledged

PDF (PC)

摘要： Squalene 1 is recognized as the precursor of sterols and polycyclic triterpenoids that play important roles in numerous life processes1. In view of the fact that the cyclization of hexa-1, 5-diene by γ-irradiation2 and some isoprenoid polyenes by photochemical method3 through radical cation intermediates have been reported and that tris (p-bromophenyl)ammoniumyl hexachloroantimonate (TBPA+SbCl6, 2) could oxidize olfines to the corresponding radical cations that underwent pericyclic reactions4, we thought it might be worthwhile to try the biomimetic cyclization of squalene initiated by radical cations. Previously we5 have reported the cyclization of geraniol and nerol to cis-p-mentha-2,8-dien-l-ol by reaction with 2. Herein, we report the cyclization of 1 initiated by 2 in dry dichloromethane to give 20-R-protosta-5,24-diene 3a and 20-S-protosta-5,24-diene 3b in the ratio of 1:1 with the total yield of 20%(Scheme 1).

Abstract: Squalene 1 is recognized as the precursor of sterols and polycyclic triterpenoids that play important roles in numerous life processes1. In view of the fact that the cyclization of hexa-1, 5-diene by γ-irradiation2 and some isoprenoid polyenes by photochemical method3 through radical cation intermediates have been reported and that tris (p-bromophenyl)ammoniumyl hexachloroantimonate (TBPA+SbCl6, 2) could oxidize olfines to the corresponding radical cations that underwent pericyclic reactions4, we thought it might be worthwhile to try the biomimetic cyclization of squalene initiated by radical cations. Previously we5 have reported the cyclization of geraniol and nerol to cis-p-mentha-2,8-dien-l-ol by reaction with 2. Herein, we report the cyclization of 1 initiated by 2 in dry dichloromethane to give 20-R-protosta-5,24-diene 3a and 20-S-protosta-5,24-diene 3b in the ratio of 1:1 with the total yield of 20%(Scheme 1).

TrendMD: