七元全碳环是天然产物合成中具挑战性的结构单元之一。本项目拟开发一类烷氧基联烯的(4+3)环加成反应，为多取代的七元碳环提供一种新的合成方法。该方法使用易制备的烷氧基联烯作为底物，在简单的氧化条件下与双烯加成可以快速构建有氧取代的七元碳环。本项目有较好的研究基础，分子间的烷氧基联烯(4+3)反应已经实现，我们还希望开发其分子内和不对称版本，并将该反应应用到复杂天然产物polygalolide A与polygalolide B的全合成中。

Seven-membered all carbon atom rings represent a challenging structural moiety in total synthesis. In this project, we would like to develop an alkoxyallene (4+3) cycloaddition reaction, which can provide a novel synthetic approach towards seven-membered rings. In this reaction, alkoxyallenes react smoothly with dienes under the treatment of DMDO, providing alpha-alkoxy cycloheptanones as the cycloadduct. By now, we have already established this method in an intermolecular manner. We also wish to develop intramolecular and asymmetric versions of this reaction. Furthermore, in this project, we will apply this (4+3) cycloaddition in the total syntheses of polygalolide A and polygalolide B.