5,5'-二甲基3,3'-二(三甲基硅基)联苯的合成

Synthesis of 5,5'-Dimethyl-3,3'-bis(trimethylsilyl)biphenyl

采用 3,5 二溴甲苯 (Ⅰ )为原料 ,与镁屑及三甲基氯硅烷 (TMSCl)按n(Ⅰ )∶n(Mg)∶n(TMSCl) =4 5∶4 9∶6 9的比例在四氢呋喃 (THF)中制得三甲基硅基 (—TMS)单保护的 5 甲基 3 溴 三甲基硅基苯 (Ⅱ ) ,产率为 85%。以此为中间体与镁屑按n(Ⅱ )∶n(Mg) =6 5∶6 6的比例制成格氏试剂后 ,与等物质的量的芳基烷 (Ⅱ )在质量分数为 5%的无水氯化镍 (NiCl2 )催化下偶联合成了 5,5′ 二甲基 3,3′ 二 (三甲基硅基 )联苯 (Ⅲ ) ,偶联产率为 78%。

Dibromotoluene(Ⅰ) reacted with magnesium and trimethylchlorosilane(TMSCl) in THF where the molar ratio was n(Ⅱ)∶n(Mg)∶n(TMSCl)=4 5∶4 9∶6 9 to afford 5 methyl 3 bromo trimethylsilyl benzene(Ⅱ) in 85% yield.5,5′ Dimethyl 3,3′ bis(trimethylsilyl)biphenyl(Ⅲ) was synthesized in 78% yield by the ligandless nickel chloride (NiCl\-2) (5%) catalyzed cross coupling reaction of aryl Grignard reagent,prepared from Ⅱ and magnsium[n(Ⅱ)∶n(Mg)=6 5∶6 6] in THF,with equimolecular Ⅱ.