Tributylstannyl Azide as Efficient Reagent in the Synthesis of Aryl

An efficient and straightforward method for one-pot synthesis of aryl azides from the corresponding amines, employing tributylstannyl azide as transfer reagent of N3 group is described. In this procedure diazotization of aryl amines occurs under mild conditions using tert-butyl nitrite (t-BuONO) and p-toluenesulfonic acid (TsOH). A variety of substituted aryl amines, with both electron-withdrawing and electron-donating groups were transformed into aryl azides in good to excellent yields. An important advantage of the present method is that, despite their high toxicity, tin byproducts can be reconverted into the starting tributylstannyl azide by treatment with sodium azide (NaN3) and reused after chromatographic separation of the aryl azide.