Synthesis and reactivity studies of α,α-difluoromethylphosphinates

The preparation and reactivity of some α,α-difluorophosphinates are investigated. Alkylation of H-phosphinates with LiHMDS and ClCF₂H gives the corresponding α,α-difluorophosphinates in good yield. Deprotonation of these reagents with alkyllithium or LDA is then studied. Subtle electronic effects translate into significant differences in the deprotonation/alkylation of the two ‘Ciba-Geigy reagents’ (EtO)₂CRP(O)(OEt)H (R=H, Me). On the other hand, attempted methylation of difluoromethyl-octyl-phosphinic acid butyl ester resulted in the exclusive alkylation of the octyl chain. Finally, reaction with carbonyl compounds results in the formation of 1,1-difluoro-2-phosphinoyl compounds.