苯硫基烯酮与不活泼烯烃的分子内[2+2]环加成反应

Intramolecular[2+2]cycloadditions of Alkyl(Phenylthio)ketenes with unactivated alkenes

为得到具有重要合成价值的多环环丁酮化合物,文章采用2-氯-1-甲基吡啶碘盐(Mukaiyama试剂)处理α-苯硫基羧酸得到α-苯硫基烯酮中间体,使其与不活泼的烯烃进行分子内[2+2]环加成反应,以20%~70%的产率得到多环环丁酮。同时研究发现,当连接烯酮和烯烃的碳链长度以及烯烃的取代受到限制时,[2+2]环加成反应不能发生,α-苯硫基烯酮会发生二聚并转化为还原二聚体和烯胺酮。

To obtain a polycyclic cyclobutanone compound having an important synthetic value,2-chloro-1-methylpyridinium iodide(Mukaiyama reagent)was used to obtain anα-(phenylthio)ketenes intermediate.Then,it reacted with unactivated alkenes to undergo intramolecular[2+2]cycloaddition,and polycyclic cyclobutanone was obtained in 20%-70%yield.The study finds that when the tether and the substitution of the alkene are limited,the[2+2]cycloaddition reaction does not occur,andα-(phenylthio)ketenes are dimerized and transformed to reductive dimmers and enaminone.