Direct phosphorylation of nucleosides by oxyphosphorane

Article abstract of DOI:10.1016/S0040-4039(97)00102-0

Ester exchange reaction of oxyphosphorane 1 with unprotected ribonucleosides cytidine 2a and adenosine 2b generated selectively spirooxyphosphoranes 3a and 3b respectively. Upon hydrolysis, the labile spirooxyphosphoranes were converted into stable ribonucleoside 2',3'-cyclic monophosphates 4a and 4b in good yields. Some polyribonucleotides were also detected from the hydrolytic products. Reaction of 1 with a 2'-deoxyribonucleoside such as thymidine 5 followed by hydrolysis afforded thymidine acyclic monophosphates (7, 8). Hence, the ester exchange reaction of oxyphosphorane might provide an efficient one-pot phosphorylation methodology for ribonucleosides and 2'-deoxyribonucleosides without any protection.