Abstract Substituted 1, 2-dihydroxy-1, 2-bisphosphonylethanes were synthesized by reacting glyoxal with phosphorous acid triesters. The intermediate adduct resulting from a nucleophilic attack of phosphorus on the carbonyl carbon was protonated and dealkylated by a third reagent such as methanol or hydrogen chloride. Evidence for the reaction mechanism was obtained by isolation and identification of dimethylether evolved as a ...