FLUORINATED TERTIARY ALCOHOLS AND ALKOXIDES FROM NUCLEOPHILIC TRIFLUOROMETHYLATION OF CARBONYL-COMPOUNDS

(CH3)3SiCF3 reacts with fluoro ketones in the presence of excess KF in CH3CN to produce alkoxides derived from formal addition of CF3- to the carbonyl carbon. These alkoxides may be isolated as such or acidified to the corresponding alcohols. Ketones to which this technique was applied include (CF3)2C = O, CF3C(O)CF2Cl, CF3C(O)CF2H, and [(CF3)2CF]2C = O. The last compound reacts with replacement of one of its perfluoroisopropyl groups by CF3. With 2 equiv of TMS-CF3, the acid fluorides RC(O)F (R = CF3CF2, n-C3F7, n-C7F15) yield products of the form RC(CF3)2OX (X = K, H) due to both substitution and addition of CF3 at the carbonyl. Similarly, F2C = O with 3 equiv of TMS-CF3 provides a novel and high-yield synthesis of the perfluoro-tert-butoxide group. Phosgene does not appear to react directly with the TMS-CF3/KF system, but is converted first to F2C = O. The intermediate ketone CF3CF2C(O)CF3 is observed in reactions of equimolar amounts of CF3CF2C(O)F and TMS-CF3.