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C[C(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.