Synthesis of Oligonucleotide RNA Containing 2´‐Deoxy‐2´‐Fluoroarabinoguanosine (2´F‐araG) for Stabilization of the Human Telomeric RNA G‐Quadruplex

This article provides detailed synthetic protocols for the preparation of RNA oligonucleotides containing 2'-deoxy-2'-fluoroarabinoguanosine (2'F-araG). Incorporation of this modification into a human telomeric RNA sequence stabilizes the G-quadruplex (G4) structure. We developed a convenient synthesis of 2'F-araG starting from commercially available 2-deoxy-2-fluoro-1,3,5-tri-O-benzoyl-α-D-arabinofuranose. The resulting 2'F-araG was converted into the corresponding 3'-phosphoramidite via a routine three-step procedure. This phosphoramidite monomer was then used for automated solid-phase RNA oligonucleotide synthesis. Finally, the resulting 2'F-araG-modified RNA oligonucleotides were employed to identify the positions that most effectively stabilize the G4 structure. © 2026 Wiley Periodicals LLC. Basic Protocol 1: Synthesis of 2´F-araG phosphoramidites Basic Protocol 2: Preparation of 2´F-araG-modified RNA oligonucleotides Basic Protocol 3: Evaluation of 2´F-araG stabilization of RNA G4 structure by circular dichroism spectroscopy.