Reactions of 2,2-bis(trifluoromethyl)oxirane with alcohols under phase transfer catalysis

It was demonstrated that the reaction of 2,2-bis(trifluoromethyl)oxirane (1) with variety of alcohols could be successfully carried out under phase transfer catalysis conditions using sodium or potassium hydroxide as a base. For example, reaction of CH3OH, C2H5OCH2CH2OH, HOCH2CH2OH with one or two moles of 1 in the presence of the catalyst [(C4H9)4N+HSO4−] gives the corresponding tertiary alcohols R[OCH2C(CF3)2OH]n (n=1 or 2) in 43–53% yield, along with some O[CH2C(CF3)2OH]2. Benzyl alcohol and phenol under similar conditions are less active, producing in the reaction with 1 the corresponding adducts ArOCH2C(CF3)2OH in 31–35% yield. Fluorinated alcohols, such as CF3CH2OH, ClCF2CH2OH, HCF2CF2CH2OH have much higher reactivity towards 1 giving ring opening products in 82–97% yield. Even in the reaction of hindered hexafluoro-iso-propanol the corresponding adduct was isolated in 43% yield. Surprisingly, the reaction of iso-propanol and epoxide 1, results in the formation of O[CH2C(CF3)2OH]2 as a major product, isolated in 56% yield. Possible mechanism for the formation of the last product was proposed.