An improved P(V)-N activation strategy for the synthesis of nucleoside diphosphate 6-deoxy-l-sugars

Four nucleoside diphosphate 6-deoxy-l-sugars have been efficiently synthesized by coupling sugar-1-phosphates prepared from the H-phosphonate precursors with nucleoside 5′-phosphoropiperidates in the presence of 4,5-dicyanoimidazole (DCI) as the activator. Compared to the conventional 1H-tetrazole-promoted phosphoromorpholidate method, the new phosphoropiperidate/DCI system significantly shortened the reaction time and afforded nucleoside diphosphate sugars in excellent isolated yields.