STUDIES ON STEREOSSPECIFIC FORMATION OF P-CHIRAL INTERNUCLEOTIDE LINKAGE. SYNTHESIS OF DIASTEREOISOMERIC 2'-DEOXYADENYLYL S-METHYLPHOSPHOROTHIOATES VIA NUCLEOSIDE HYDROXYL ACTEVATION

Article abstract of DOI:10.1016/S0040-4020(01)88054-6

Substitution of 4-nitrophenoxy group at phosphorus atom of 5'-O-monomethoxytrityl-2'-deoxyadenosine 3'-O- (4) <(Sp)-4:(Rp)-4=90:10 and (Sp)-4:(Rp)-4=30:70> by base-activated 5'-hydroxyl function of 3'-O-tert-butyldimethylsilyl-2'-deoxyadenosine (5)gives fully protected P-chiral 2'-deoxyadenylyl(3',5') 2'-deoxyadenosine S-methylphosphorothioates (6), <(S)-6:(Rp)-6=92:8 and (Sp)-6:(Rp)-6=32:68 respectively>.Demethylation of internucleotideS-methylphosphorothioate group in 6 and deprotection of 3'-and 5'-hydroxyl functions lead to diastereoisomeric mixture of 2'-deoxyadenylyl(3',5')2'-deoxyadenosine-O,O-phosphorothioates (7).