Transannular Diels–Alder/1,3-Dipolar Cycloaddition Cascade of 1,3,4-Oxadiazoles: Total Synthesis of a Unique Set of Vinblastine Analogues
作者:Erica L. Campbell、Colin K. Skepper、Kuppusamy Sankar、Katharine K. Duncan、Dale L. Boger
DOI:10.1021/ol402549n
日期:2013.10.18
A powerful tandem [4 + 2]/[3 + 2] cycloaddition cascade of 1,3,4-oxadiazoles initiated by a transannular [4 + 2] cycloaddition is detailed. An impressive four rings, four carbon–carbon bonds, and six stereocenters are set on each site of the newly formed central six-membered ring in a cascade thermal reaction that proceeds at temperatures as low as 80 °C. The resulting cycloadducts provide the basis
详细介绍了由跨环 [4 + 2] 环加成引发的 1,3,4-恶二唑的强大串联 [4 + 2]/[3 + 2] 环加成级联。令人印象深刻的四个环、四个碳-碳键和六个立体中心设置在新形成的中心六元环的每个位点上,以在低至 80 °C 的温度下进行级联热反应。由此产生的环加合物为合成长春碱的独特类似物提供了基础,该类似物在天然产物的文多林衍生亚基的 C3/C4 中心含有代谢良性的深层环状修饰。