An efficient, catalyst free, 1,3-dipolar cycloaddition strategy to conjugate nucleosides and nucleotides with isoxazoles under atmospheric conditions and in an aqueous environment is reported. The protocol involves chloramine-T as a practical reagent to induce in situ nitrile oxide formation and the alkyne partner is attached to the sugar residue or the nucleobase. The reactions are regiospecific, fast and high yielding.