A polymer-bound α,β-methylene-β-triphosphitylating reagent was synthesized and subjected to reactions with unprotected nucleosides, followed by oxidation, deprotection of cyanoethoxy groups, and acidic cleavage to afford nucleoside 5′-O-α,β-methylene-β-triphosphates. Among all the compounds, cytidine 5′-O-α,β-methylene-β-triphosphate inhibited RNase H activity of HIV-1 reverse transcriptase with a Ki value of 225 μM