碳钯化/C-H烯基化串联反应:含氧化吲哚类结构单元的轴手性烯基芳烃的不对称合成

Asymmetric Synthesis of Axial Chiral Vinylarenes Fearturing Oxindole Moiety via Tandem Carbopalladation/C-H Olefination

由于较低的旋转能垒,轴手性烯基芳烃衍生物的催化不对称合成存在很大挑战.氧化吲哚是天然产物的重要骨架,也是生物活性分子及药物的重要合成子.作者通过碳钯化/C-H键的烯基化串联反应实现了含氧化吲哚类结构单元的轴手性烯基芳烃的不对称合成.(4R,5R)-2,2-二甲基-α,α,α',α'-四苯基-1,3-二氧戊环-4,5-二甲醇(TADDOL)衍生的亚膦酰胺配体给出了较好的产率和中等的对映选择性.产物在110℃加热10 h后ee值没有降低,表明其手性轴具有很好的热稳定性.

Due to the lower configuration stability of vinylarenes,arsing from the relatively lower rotational barriers,their catalytic asymmetric synthesis remains a daunting task.Oxindoles moiety are privileged framework of natural products and building blocks of bioactive molecules as well as pharmaceuticals.The asymmetric synthesis of axial chiral vinylarenes fearturing oxindole moiety via sequential carbopalladation/C-H olefination from readily available materials with palladium catalysis has been developed.(4R,5R)-(-)-2,2-Dimethyl-α,α,α',α'-tetraphenyl-1,3-dioxolane-4,5-dimethanol(TADDOL)-derived phosphoramidite gave products with good yield and moderate ee value.The erosion of optical purity was not observed even after heating the product for 10 h at 110℃,which indicates the excellent stability of the chiral axial.