Perfluoro-1-pentafluorophenyl-1-alkynes and the corresponding Ï-chloroperfluoro compounds are conveniently prepared by the following two-step sequence: Reaction of methylenetriphenylphosphorane with hexafluorobenzene followed by C-acylation of the resultant perfluorobenzylidenetriphenylphosphorane (without isolation) with perfluoroalkanoic anhydrides or Ï-chloroperfluoroalkanoyl fluorides, respectively, to give α-perfluoroacyl [or α-(Ï-chloroperfluoroacyl)]-perfluorobenzylidenetriphenylphosphoranes and pyrolysis of these latter compounds at 230-260°C/2 torr. The second step of the sequence represents an intramolecular Wittig reaction.
全氟-1-
五氟苯-1-炔和相应的Ï-
氯全氟化合物可通过以下两个步骤方便地制备:先将亚甲基
三苯基膦与
六氟苯反应,然后将生成的
全氟亚苄基
三苯基膦(未经分离)与
全氟烷酸酐或Ï-
全氟氯烷酰
氟进行 C-酰化反应、 分别生成δ±-
全氟酰基[或δ±-(Ï-
氯全
氟乙酰基)]-
全氟亚苄基
三苯基膦,并在 230-260°C/2 托条件下热解后一种化合物。该过程的第二步是分子内维蒂希反应。