title: Understanding high diastereomeric discrimination in formation of oligoribonucleotide phosphorothioate linkages: the first study of pKa-dependent activation in solid-supported coupling of 2'-O-substituted ribonucleoside phosphoramidites.
abstract: Activation of 2'-O-substituted ribonucleoside phosphoramidites with various activators during solid-supported synthesis of phosphorothioate oligonucleotides was studied. The Rp:Sp diastereomeric composition of resulting phosphorothioate linkage dependent on pKa of activator utilized for coupling.
authors.affiliation: Isis Pharmaceuticals, Carlsbad, California 92009, USA. vravikumar@isisph.com
authors.forename: Vasulinga T
authors.initials: VT
authors.lastname: Ravikumar
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Cole
mesh_terms: D007202:Indicators and Reagents; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D009943:Organophosphorus Compounds; D010710:Phosphates; D012265:Ribonucleotides / Q000138:chemical synthesis
chemical_list: D007202:Indicators and Reagents; D009843:Oligoribonucleotides; D009943:Organophosphorus Compounds; D010710:Phosphates; D012265:Ribonucleotides; C434331:phosphoramidite; C083120:phosphorodithioic acid