Direct and selective metal-free N⁶-arylation of adenosine residues for simple fluorescence labeling of DNA and RNA

We have developed an unprecedented transition metal-free approach for the direct fluorescence turn-on labeling of natural oligonucleotides through selective N⁶-arylation of adenosine moieties. This method allows the simple and direct fluorescence labeling of natural unmodified DNA and RNA, but is dependent on the secondary structure, favoring single-stranded structures.