α-Chloro acylphosphonates and α, α′-dichloro bisacylphosphonates were prepared in situ by chlorination of acylphosphonates and bisacylphosphonates, respectively, using sulfuryl chloride. Subsequently, they were cleaved to the corresponding α-chlorinated or α, α′- dichlorinated (di) carboxylic acids with a hydrogen peroxide–sodium bicarbonate system. Performing the cleavage with an alcohol or an amine yielded the corresponding α- ...