Solid-Phase Synthesis of <i>P</i>‑Boronated Oligonucleotides by the <i>H</i>‑Boranophosphonate Method

Recently, <i>P</i>-boronated oligonucleotides have been attracting much attention as potential therapeutic oligonucleotides. In this study, we developed <i>H</i>-boranophosphonate oligonucleotide bearing a borano group and hydrogen atom on the internucleotidic phosphorus and demonstrated that this novel <i>P</i>-boronated oligonucleotide is a versatile precursor to various <i>P</i>-boronated oligonucleotides such as boranophosphate, boranophosphorothioate, and boranophosphoramidate. The method was also applicable to the synthesis of a locked nucleic acid-modified boranophosphate oligonucleotide, which exhibited a dramatically enhanced affinity to complementary oligonucleotides