Tetrabutylammonium Iodide-Catalyzed Oxidative α-Azidation of β-Ketocarbonyl Compounds Using Sodium Azide

Abstract

We herein report the oxidative α-azidation of carbonyl compounds by using NaN3 in the presence of dibenzoylperoxide catalyzed by tetrabutylammonium iodide (TBAI). By utilizing these readily available bulk chemicals a variety of cyclic β-ketocarbonyl derivatives can be efficiently α-azidated under operationally simple conditions. Control experiments support a mechanistic scenario involving in situ formation of an ammonium hypoiodite species which first facilitates the α-iodination of the pronucleophile, followed by a phase-transfer catalyzed nucleophilic substitution by the azide. Furthermore, we also show that an analogous α-nitration by using NaNO2 under otherwise identical conditions is possible as well.