The prooligonucleotide approach: Synthesis of mixed phosphodiester and SATE phosphotriester prooligonucleotides using H-phosphonate and phosphoramidite chemistries

Abstract

The synthesis of mixed SATE-phosphotriester and phosphodiester prooligonucleotides using both phosphoramidite and H-phosphonate chemistries is described. The key step is the selective oxidation of phosphite triester and H-phosphonate linkages to yield thiono- or oxo-triester SATE and thiono- or oxo-diester linkages. This approach allows the synthesis of any desired mixed prooligos bearing either tBu- or Me-SATE enzymolabile protecting groups.