Difluorocarbene Precursor for Difluoromethylation

Diethyl (Bromodifluoromethyl)phosphonate is a difluorocarbene precursor. The P-C bond can be hydrolyzed by KOH at -78 °C to room temperature to generate difluorocarbene (:CF₂). When using phenols as substrates, the corresponding difluoromethyl ethers can be obtained via difluoromethylation in good yields. This reaction proceeds under very mild conditions, thus, even phenols bearing enolizable groups can be difluoromethylated at their phenolic hydroxy groups.