Enantioselective Photocycloaddition of 3‑Hydroxyflavones: Total Syntheses and Absolute Configuration Assignments of (+)-Ponapensin and (+)-Elliptifoline

We have previously reported development of biomimetic,
asymmetric
[3 + 2] photocycloadditions between 3-hydroxyflavones and cinnamate
dipolarophiles to access (−)-rocaglamide and related natural
products. Herein, we describe enantioselective syntheses of aglain
cycloadducts leading to the first total syntheses and absolute configuration
assignments of the aglain natural products (+)-ponapensin
and (+)-elliptifoline.

我们此前曾报道了以3-羟基黄酮与肉桂酸酯亲偶极体为底物的仿生不对称[3+2]光环加成反应的开发工作，该反应可用于合成(-)-罗卡酰胺(rocaglamide)及其相关天然产物。本文中，我们报道了阿格莱恩类环加成产物的对映选择性合成方法，借此首次实现了阿格莱恩类天然产物(+)-波纳新(ponapensin)与(+)-椭圆叶碱(elliptifoline)的全合成，并完成了其绝对构型的确定。