New synthesis of hydrofluoroethers

Polyfluorinated ethers RfCH2ORf react with fluoroethylenes in the presence of SbF5 catalyst under mild conditions. The reaction of CF3CH2OCF2CF2H (1a) with terafluoroethylene rapidly proceeds at ambient temperature and results in high yield formation of CF3CH2OCF(C2F5)CF2H, along with small amount of CF3CH2OC(C2F5)2CF2H. On the other hand, the condensation of 1a with trifluoroethylene proceeds with formation of CF3CH2OC(CFHCF3)2CF2H as a major product.