Metal free click chemistry on nucleosides and oligonucleotides

<p>Chemoselective ligation of biologically significant moieties through azide alkyne ClickChemistry has recently received much attention1. The reaction is attractive in that itregioselectively affords stable triazole linked bioconjugated products under mild conditions.However, from the view point of the synthetic oligonucleotide chemist, a significantdisadvantage is that the non-thermal reaction requires an in situ generated Cu (I) catalyst.Unwanted Cu (I) mediated chemistry, specifically oxidative degradation etc.</p>