Solid-phase synthesis and properties of stereocontrolled boranophosphate/phosphate and phosphorothioate/phosphate chimeric oligouridylates

This study describes the stereoselective synthesis of boranophosphate/phosphate (PB/PO) and phosphorothioate/phosphate (PS/PO) chimeric oligouridylates using the solid-phase method. Oxazaphospholidine monomer was used to construct the stereodefined PB and PS linkages. The study introduces modifications to oligouridylate derivatives in the intended positions with the intended stereochemistry of phosphorous atoms. Additionally, biophysical and biochemical properties of the synthesized oligomers were evaluated. Notably, it was found that a (Sp)-PB/PO chimeric oligouridylate had higher hybridization ability than the unmodified counterpart to an unmodified oligoadenylate. This is the first report that elucidates the effect of both stereochemistry and type of P-modification (PB and PS) on properties of oligoribonucleotides.