Bioinspired Polyene Cyclization Promoted by Intermolecular Chiral Acetal-SnCl<sub>4</sub> or Chiral <i>N</i>-Acetal-TiCl<sub>4</sub>: Investigation of the Mechanism and Identification of the Key Intermediates
作者:Yu-Jun Zhao、Teck-Peng Loh
DOI:10.1021/ja802896n
日期:2008.7.1
New strategies using chiral acetal or chiral mixed-acetal in the presence of Lewis acids (SnCl4 or TiCl4) to promote polyene cyclization reaction are described. Acetal-promoted and mixed-acetal-promoted polyene cyclization products are very versatile and can easily be converted into various optically active tricyclic and tetracyclic terpenoids. One of the derivatives of the cyclization products was
描述了在路易斯酸(SnCl4 或 TiCl4)存在下使用手性缩醛或手性混合缩醛促进多烯环化反应的新策略。缩醛促进和混合缩醛促进的多烯环化产物用途广泛,可以很容易地转化为各种光学活性的三环和四环萜类化合物。单次重结晶后,环化产物的衍生物之一可达到 96% ee。此外,发现氧代碳鎓中间体对此类反应具有良好的不对称选择性。