One-flask synthesis of dinucleoside tetra- and pentaphosphates

We report a one-flask route for the synthesis of dinucleoside tetra- and pentaphosphates, in isolated yields of 50-85%. This route relies on a mixture of P(Ill) and P(V) chemistries, using phosphitylation of a protected nucleoside with 2-chloro-4H-1,3,2-benzo-dioxaphosphorin-4-one (salicylchlorophosphite), followed by sequential reaction with inorganic pyrophosphate and a nucleoside 5' mono- or diphosphate.