The first synthesis of polyflavanostilbene B (1), which has seven contiguous stereocenters including two quaternary carbon centers, from abundant polymeric (−)‐epicatechin gallate on a gram scale in three steps without the use of protecting groups is reported. The key transformations of this strategy include a regioselective and stereoselective substitution of resveratrol to give the 4‐derivative of (−)‐epicatechin 3‐gallate and an iron‐catalyzed cyclization reaction. The possible radical cyclization mechanism in the formation of the hexahydrocyclopenta[c]furan core is also discussed.

中文翻译：

---

铁催化六氢环戊五烯[c]呋喃核的合成及全黄酮B的简捷合成

据报道，在不使用保护基的情况下，可以在3步内由克数丰富的聚合（-）-表儿茶素没食子酸酯以3个步骤合成具有七个连续立体中心（包括两个季碳中心）的聚黄烷二茂烯B（1）。该策略的关键转变包括白藜芦醇的区域选择性和立体选择性取代，生成（-）-表儿茶素3-没食子酸酯的4-衍生物和铁催化的环化反应。还讨论了六氢环戊[c]呋喃核形成中可能的自由基环化机理。