作者:Tao Zheng、Radha S. Narayan、Jennifer M. Schomaker、Babak Borhan
DOI:10.1021/ja043002i
日期:2005.5.1
A simple and efficient process to cyclize triols containing a 1,2-diol functionality with a pendant hydroxyl group is presented. The one-pot procedure converts the 1,2-diol into an ortho ester in situ, which upon treatment with a Lewis acid generates a cyclic acetoxonium intermediate. This intermediate is subsequently trapped by the pendant hydroxyl group to generate a cyclic ether. The stereochemistry
提出了一种简单有效的方法来环化含有 1,2-二醇官能团和侧羟基的三醇。一锅法将 1,2-二醇原位转化为原酸酯,在用路易斯酸处理后生成环状丙酮鎓中间体。该中间体随后被侧羟基捕获以生成环醚。1,2-二醇的立体化学完全保真(在环化位点反转)转移到产物中,反应以高区域选择性进行。该过程类似于路易斯酸催化的带有羟基的环氧化物分子内开环,产生具有区域和立体化学控制的各种尺寸的环醚。