SOLID-PHASE STEREOSELECTIVE SYNTHESIS OF 2'-O-METHYL-OLIGORIBONUCLEOSIDE PHOSPHOROTHIOATES USING NUCLEOSIDE BICYCLIC OXAZAPHOSPHOLIDINES

The use of 2'-OMe-ribonucleoside bicyclic oxazaphospholidines derived from (R)- or (S)-2-pyrrolidinemethanol has enabled the stereoselective synthesis of (R-p)-, and (S-p)-2'-O-methyloligoribonucleoside phospho rothioates. Interestingly, higher stereoselectivity (96-98%) was obser ved in the synthesis of (S-p)-2'-O-methyl-oligoribonucleoside phosphor othioates compared to that in the case of(S,)oligodeoxyribonucleoside phosphorothioates (90%). (C) 1998 Published by Elsevier Science Ltd. A ll rights reserved.