Biomimetic type approach to the tricyclic core of xyloketals. Application to a short, stereocontrolled synthesis of alboatrin and first synthesis of xyloketal G
作者:Debayan Sarkar、Ramanathapuram V. Venkateswaran
DOI:10.1016/j.tet.2011.04.084
日期:2011.6
benzopyran ring system of xyloketals is described. An orthoester Claisen rearrangement of a chromenol and an intra-molecular cationic cyclization are the key steps in the synthesis. A short, stereocontrolled and high yield synthesis of the phytotoxic metabolite alboatrin was achieved employing this strategy. A unique case of Lewis acid catalyzed isomerization of epi-alboatrin to alboatrin was observed.
描述了一种简便的方法来制备木酮缩醛的线性四氢呋喃苯并吡喃环系统。苯甲醇的原酸酯克莱森重排和分子内阳离子环化是合成中的关键步骤。利用这种策略,实现了短时,立体控制和高收率的植物毒性代谢物白蛋白的合成。的路易斯酸的唯一情况下催化的异构化外延-alboatrin到alboatrin进行了观察。随后该方法延长了xyloketal G,其中三个步骤即的一锅反应,乙酰化,异构化和脱甲基化的去甲混合物的乙酰化过程中出现的第一个全合成ö甲基xyloketal G和去甲ö甲基EPI在AlCl 3存在下木酮基G以非常好的总产率提供木酮基G。