Demethylation of dimethyl phosphonate esters with sodium ethanethiolate: Improved synthesis of 5′-methylene substituted 2′,5′-deoxyribonucleotides

We describe a new demethylation method for dimethyl phosphonate esters using sodium ethanethiolate. The new procedure allows demethylation of nucleoside dimethyl phosphonate esters without 1′-α-anomerization, providing an improved synthesis of 5′-methylene substituted 2′,5′-deoxynucleotides.