The reaction of activated RNA species with aqueous fluoride ion: a convenient synthesis of nucleotide 5′-phosphorofluoridates and a note on the mechanism

The chemistry of 5′-phosphorimidazolides of ribonucleosides is extended to include their reaction with alkali metal fluorides in aqueous solution. High yields of 5′-phosphorofluoridates are formed, especially with potassium fluoride, but no detectable oligomerization products were formed. A combination of HPLC, mass spectrometry, synthesis, kinetics, and NMR confirms the identities of the products. Judicious control of pH leads to higher yields in shorter reaction times. This new methodology contrasts favorably with other synthetic routes involving non-aqueous chemistry or aqueous chemistry with a nucleotide triphosphate.