Stereocontrolled synthesis of oligodeoxyribonucleoside boranophosphates by an oxazaphospholidine approach using acid-labile N-protecting groups

Oligodeoxyribonucleoside boranophosphates (PB-ODNs) were synthesized in a stereocontrolled manner via the corresponding H-phosphonates with fully deprotected nucleobases by using diastereopure 2′-deoxyribonucleoside 3′-O-oxazaphospholidine monomers bearing acid-labile protecting groups on the nucleobases. Using the resultant stereodefined PB-ODNs, we demonstrated that the thermal stability of the duplexes of PB-ODNs with complementary oligonucleotides was dependent on the configuration of their phosphorus atoms.