Penta-2,4-dien-1-ones by Formal [3+2] Cycloaddition-Rearrangement of Electron-Deficient Diethyl 2-(Dicyanomethylene)malonate with Alkynes
作者:Etienne J. Donckele、Tristan A. Reekie、Nils Trapp、François Diederich
DOI:10.1002/ejoc.201501473
日期:2016.2
The reactions of diethyl 2-(dicyanomethylene)malonate, an electron-deficient alkene, with donor-activated and unactivated alkynes have been investigated. Moderately electron-rich and unactivated alkynes undergo efficient formal [3+2] cycloaddition–rearrangement cascades to provide the corresponding penta-2,4-dien-1-one adducts in yields of up to 84 %. The structures of the solid dienone products were
已经研究了 2-(二氰基亚甲基)丙二酸二乙酯(一种缺电子烯烃)与供体活化和未活化的炔烃的反应。中等富电子和未活化的炔烃经过有效的正式 [3+2] 环加成 - 重排级联反应,以高达 84% 的产率提供相应的 penta-2,4-dien-1-one 加合物。固体二烯酮产物的结构通过X射线衍射分析证实。二烯酮中的buta-1,3-diene 部分不采用平面s-trans 构象,而是采用非平面几何结构,其中两个烯键几乎彼此正交。这种转化以优异的区域选择性和广泛的炔烃进行,无需催化剂。在优化的反应条件下,