Synthesis and properties of siRNAs containing 5′-amino-2′,5′-dideoxy-2′α-fluororibonucleosides

Short interfering RNAs (siRNAs) containing P3′→N5′ phosphoramidate linkages were successfully synthesized by introducing 2′-deoxy-2′-fluororibonucleoside and 5′-amino-2′,5′-dideoxy-2′α-fluororibonucleoside in succession. It was found that the introduction of 5′-amino-2′,5′-dideoxy-2′α-fluororibonucleosides into siRNAs improved the nuclease-resistant properties of the siRNAs without loss of their silencing efficacy.