Hydrolysis of phosphoranes containing a perfluoropinacolyl ring

Abstract

The hydrolysis of phosphoranes Ph2P(pfp)Cl, Ph2P(pfp)OR, PhP(pfp)(OR)2, and (RO)3P(pfp), containing a perfluoropinacolyl (pfp) ring, occurs under neutral, basic, or acidic conditions and leads to the formation of acyclic perfluoropinacolyl products, i.e. R2P(O)OC(CF3)2C(CF3)2OH, as determined by 1H, 19F, 31P, 13C nmr and ir studies. In the presence of a base, all trifluoromethyl groups in Ph2P(O)OC(CF3)2C(CF3)2OH are equilibrated, as verified by 19F and 13C nmr; and from the variable temperature 19F nmr line-shape analysis the activation parameters for this exchange process were found to be: Ea = 36.0 ± 3 kJ mol−1, ΔH≠ = 33.5 ± 3 kJ mol−1, ΔS≠ = −86 ± 8 J K−1 mol−1, [Formula: see text]. The reactions of phosphoranes with HF were briefly investigated.