不对称（4+3）环加成反应是构建手性七元环化合物的有效途径之一。在环加成反应的众多前体中，钯稳定的两性离子，特别是钯三亚甲基甲烷在环加成反应中得到了广泛应用。然而，官能团化三亚甲基甲烷前体用于手性七元环衍生物的合成尚未实现。本项目通过将炔基官能团引入三亚甲基甲烷前体，设计、发展一类结构新颖的三个碳的合成子用于不对称（4+3）环加成反应，实现手性七元环化合物，特别是含七元环的并环骨架结构的简洁、高效构建，并获得优异的区域选择性和对映选择性。环加成产物可经官能团化反应进一步转化为愈创木内酯骨架。本项目的顺利开展将为新型全碳合成子的设计和发展提供新方向，为手性七元环衍生物的制备提供新方法，为愈创木内酯类天然产物全合成及它们在化学生物学及药物化学中的应用研究服务。

The asymmetric (4+3) cycloaddition reaction is one of the effective ways to construct chiral seven-membered rings. Among these reactive species, palladium-stabilized zwitterions, especially palladium-trimethylenemethane (TMM) intermediates, have a wide application in cycloaddition reactions. However, synthesis of chiral seven-membered ring by using functionalized trimethylenemethane precursors has not been achieved. This project will devise a novel three-carbon synthon for the trimethylenemethane generation that incorporates an alkynyl moiety. Trimethylenemethane from these precursors would readily react with conjugated dienes to yield chiral seven-membered rings, particularly those with fused-ring systems, with good chemo-, regio- and enantioselectivity. The cycloaddition product can be further converted to the guaianolide skeleton by a structural elaboration. Furthermore, this project will provide a new direction for the design and development of novel full-carbon synthons as well as new methods for the preparation of chiral seven-membered rings，and it will play a vital role in chemical biology and pharmaceutical chemistry area.