| abstract |
New methods of synthesizing mono- and oligo- nucleotide H-phosphonates are disclosed. The methods comprise contacting a mononucleoside with phosphonic acid and benzoyl anyhydride to yield the corresponding mononucleoside H-phosphonate. Preferrably a catalytic amount of triphosgene is also used. A similar procedure can be used to couple a first mononucleoside to a second mononucleoside or to an oligonucleotide, the method comprising contacting, in the presence of benzoic anhydride and, preferrably, a catalytic amount of triphosgene, a mononucleotide or oligonucleotide having a free 5' hydroxyl with a mononucleoside having a 3' hydroxyl-bearing phosphorous moiety (preferably H-phosphonate). |