A study of the reaction of perfluoroalkyl Grignard reagents with phosphoryl chloride and phenylphosphonic dichloride

Abstract

Perfluoroalkyl Grignard reagents react with phosphoryl halides at -78 °C to room temperature to selectively produce bis(perfluoroalkyl)phosphonyl halides, which after aqueous work up, give bis(perfluoroalkyl)phosphinic acids in high overall yields. Reaction of perfluoroalkyl Grignards with phenylphosphonic dichloride gives high yields of bis(perfluoroalkyl)phenyl phosphine oxides which are readily hydrolysed to perfluoroalkyl(phenyl)phosphinic acids.

Polyfluorinated Ethanes as Versatile Fluorinated C2-Building Blocks for Organic Synthesis

“…An efficient pathway toward perfluoroalkylphosphinic acids was elaborated by Caffyn . Pentafluoroethyl magnesium bromide was prepared from perfluoroethyl iodide by transmetalation with EtMgBr to form less basic organometallics.…”

“…329 An efficient pathway toward perfluoroalkylphosphinic acids was elaborated by Caffyn. 330 Pentafluoroethyl magnesium bromide was prepared from perfluoroethyl iodide by trans- metalation with EtMgBr to form less basic organometallics. The reaction of this perfluoroethyl Grignard reagent with phosphoryl chloride gave selectively bis(perfluoroalkyl)phosphonyl chloride 275a, which afforded bis(perfluoroethyl)phosphinic acid 235n after aqueous workup.…”

Perfluoroalkyl Grignard Reagents: NMR Study of 1-Heptafluoropropylmagnesium Chloride in Solution

“…In analogy with normal Grignard reagents, F RMgX reacts with electrophiles leading to organofluorine compounds . However, in practice, the applications have been quite limited due to poor stability and reactivity .…”