Reactions of novel unsaturated fluorocarbons

Novel fluorinated mono-enes and di-enes have been synthesised via telomerisation reactions using (CF3)2CFI with CF2CH2 and also with CF2CFH. Cyclo-additions with diazomethane occur readily to give Δ1 or Δ2 pyrazolines, depending on the system, and nucleophilic attack occurs with methanol and with fluoride ion. In the latter case, stable carbanions have been observed. A novel free-radical route to seven-membered rings, arising from cyclo-addition of dimethyl- and diethyl-ethers to the diene [(CF3)2CCHCF2–]2 (3), has been developed.