Synthesis of (R)- and (S)-ßhydroxyphosphonate acyclonucleosides: structural analogues of Adefovir (PMEA)

A synthetic pathway to new acyclonucleoside phosphonates, as analogues of Adefovir, is described. The reduction of an acyclonucleoside ß-ketophosphonate, readly available from the nucleobase and benzyl-acrylate, afforded a mixture of (R)- and (S)-ß-hydroxyphosphonate derivatives which was resolved. The assignment of the absolute configuration was proposed on the basis of NMR studies and was supported by molecular modelling studies.