Tetraisopropyl methylenediphosphonate used in the synthesis of unsaturated phosphonocholines with enantioselective effects on neuronal tumor cell proliferation and viability. Also is used in the preparation of E2-bisphosphonate conjugates as potential anti-osteoporosis agents and in the preparation of AZT 5’-Triphosphate compounds, which display inhibitory effects on HIV-1 reverse transcriptase.