Site-Selective Conversion of Azido Groups at Carbonyl α‑Positions to Diazo Groups in Diazido and Triazido Compounds

This paper reports on the selective
conversion of alkyl azido groups
at the carbonyl α-position to diazo compounds. Through β-elimination
of dinitrogen, followed by hydrazone formation/decomposition, α-azidocarbonyl
moieties were transformed into α-diazo carbonyl groups in one
step. As these reaction conditions do not involve aryl or general
alkyl azides, site-selective conversions of di- and triazides were
achieved. Through this method, the successive site-selective conjugation
of the triazido molecule with three different components is demonstrated.