Highly efficient nitrobenzene and alkyl/aryl azide reduction in stainless steel jars without catalyst addition

The mechanochemical and selective reduction of aryl nitro and aryl/alkyl azide derivatives, with either formate salts or hydrazine, to the corresponding, synthetically useful amines occurs in excellent yields in a planetary ball mill without the addition of a catalyst. This newly developed and solvent-free protocol is efficient, fast and does not require the addition of a metal hydrogenation catalyst as the stainless steel jar itself fulfils that role. The method has been applied to a broad range of compounds and excellent yields have been obtained. The formylation of alkyl amines has been successfully performed, by means of mechanochemical activation, in the presence of ammonium formate alone.