Stereocontrolled synthesis of phosphorothioate DNA by an oxazaphospholidine approach.

Abstract

Stereocontrolled synthesis of oligodeoxyribonucleoside phosphorothioates using nucleoside 3'-O-oxazaphospholidine derivatives as monomer units is described. N-(Cyanomethyl)pyrrolidinium triflate (CMPT) was found to be effective as an activator for the highly diastereoselective internucleotidec bond formation. The present method was applied to the solid-phase synthesis of stereoregulated oligodeoxyribonucleoside phosphorothioates.