Facile Synthesis of a Phosphotriester Intermediates for Solution-Phase Preparation of Oligonucleotide Phosphorothioates

Fully protected 2ʹ-deoxynLicleoside phosphorothioale triester derivatives, which are key starting materials for the largescale solution-phase preparation of phosphorothioate oligomicleotides, were easily synthesized by a new method starting from common, fully protected 2ʹ-deoxynucleosides.