Dealkylation of Dialkyl Phosphonates with Boron Tribromide

Boron tribromide cleanly and quantitatively converts dimethyl-, diethyl-, diisopropyl-, and ditertiobutyl phosphonates RP(O)(OR′)2 into the corresponding phosphonic acids RP(O)(OH)2 via methanolysis. The use of boron tribromide is compatible with a variety of functionalities in the R group.