Synthesis of oligodeoxyribonucleoside phosphorothioates using Lawessonʹs Reagent for the Sulfur Transfer Step

2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawessonʹs reagent) efficiently converts the triphosphite intermediate used in the solid-phase synthesis of oligonucleotides into an oligodeoxyribonucleoside phosphorothioate.