Natural pentacyclic triterpenoids are important secondary metabolites, which have attracted interest due to the wide range of their biological activities. Oleanolic, ursolic acids and betulin, are the most known compounds of this group, which are isolated from various plants. However, the medicinal application of these natural products are hindered by their extremely low water solubility and thus – low bioavailability. One option to overcome this limitation is introduction of polar anionic functional groups such as phosphates and sulfates, which, however, are prone to hydrolysis. Here we describe the synthesis of novel anionic triterpenoid phosphonates, which bear methylene-bridged anionic phosphonate group side chain and exhibit excellent water solubility.