C-Si bond formation and fluoro(2.2)cylophane synthesis by C-F bond activation

氟代环芳已被认为是用于大规模半导体制造的热稳定绝缘体聚合物的有前途的单体。为了开发一种实用的合成环蕃的方法，人们对镁促进的C-F键活化进行了广泛的研究。在DMF中，在三甲基硅烷的存在下，双三氟甲基苯与镁反应，得到了一种新的合成方法。该反应以50-60%的产率提供所需的三甲基甲硅烷基化苄基化合物。氟化物催化脱硅基脱溴得到所需的环蕃通过醌二甲烷，产率为53%。从双三氟甲基苯的可获得性来看，本方法将与基于Zn-金属促进的脱氯制备的Dolbier方法竞争。

Fluorocyclophanes have been recognized as a promising monomer for thermally stable insulator polymer useful for large scale semiconductor manufacturing. In order to develop a practical synthetic method for the cyclophane, Mg-promoted C-F bond activtion has been extensively studied. And one of the protocol for the purpose has been found which consists of reaction of bistrifluoromethyl benzene wirh magnesium in the presence of trimethylsilane in DMF. The reaction provided the desired trimethylsilylated benzyl compound in 50-60% yields. Fluroride-catalyzed desilylated defluorination gave the desired cyclophane via quinodimethane in 53% yield. The present method will be competitive to the Dolbier method based on Zn-metal promoted dechlorinative preparation from the point of availability of bistrifluoromethylbenzene.