Fluorinated phosphorus compounds: Part 1. The synthesis and reactions of some fluoroalkyl phosphoryl compounds

Fluoroalkyl phosphorochloridates CF3CH2OP(O)Cl2 and (RFCH2O)2P(O)Cl (RF=CF3, C2F5) were prepared from phosphorus oxychloride, fluoroalcohols and triethylamine, but selective substitution was difficult. Phosphates (RFCH2O)2P(O)OR (RF=CF3, C2F5 and R=Me, Et, n-Pr, i-Pr) were isolated in yields of 38–84% from the reactions of the phosphorochloridates with alcohols and triethylamine. Success of the inverse reaction, i.e. ROP(O)Cl2 and RFCH2OH, depended on the R group (Me, Et) and the RF group (CF3, C2F5). The phosphates did not react with bromotrimethylsilane in chloroform. Addition of amines to CF3CH2OP(O)Cl2 or (CF3CH2O)2P(O)Cl gave phosphoramidates (RR′N)2P(O)OCH2CF3 or (CF3CH2O)2P(O)NRR′ (R and R′=H, Me, Et) in yields of 58–75%. The inverse reactions of Me2NP(O)Cl2 and (Me2N)2P(O)Cl with trifluoroethanol were slow, but were catalysed by 4-dimethylaminopyridine. Anhydrous hydrogen chloride split one of the P–N bonds of (Me2N)2P(O)OCH2CF3 to give Me2NP(O)Cl(OCH2CF3), but was without action on (CF3CH2O)2P(O)NMe2.