New partially fluorinated epoxides by oxidation of olefins with sodium hypohalites under phase transfer catalysis

Partially fluorinated epoxides can be readily prepared by oxidation of the corresponding olefins by NaOCl (or NaOBr) under phase transfer catalysis (PTC) conditions. Oxidation of CH₂C(CF₃)₂ at 0-5 °C leads to the formation of 2,2-bis(trifluoromethyl)oxirane in 65-75% yield. (CF₃)₂CCHCH₂X (X=Cl or Br) were converted into the corresponding epoxides in 24-31% yield by the action of NaOCl and NaOBr, respectively. Baylis-Hillman adducts of fluorinated ketones and esters of acrylic acid CH₂CC(OH)(CF₂X)Y]C(O)OR] X=F or Cl, Y=CF₃, CF₂Cl or C(O)OCH₃ and R=CH₃ or C(CH₃)₃] were converted into α-hydroxyepoxides in 47-84% yield under action of NaOCl in the presence of PT catalyst. Oxidation of tert-butyl ester of α-trifluoromethylacrylic acid by NaOCl rapidly proceeds at ambient temperature with formation of epoxide in 75% yield. Oxidation of (C₂F₅)₂CCHC₃F₇ results in the high yield formation of trisubstituted epoxide.