Catalytic Aerobic Oxidation of Hydrazines into 2‐Tetrazenes

Abstract

Dedicated to Holger Braunschweig on his 60th birthday, for his continued support and inspiration.We report a catalytic formation of 2-tetrazenes by copper (ii) promoted oxidation of hydrazines in the presence of bipyridine ligands, that uses air or dioxygen as terminal oxidant. The method was applied to a series of hydrazines, delivering symmetrical tetrazenes, which were previously prepared using toxic or stoichiometric oxidants. The catalytic reaction could be used for the formation of a cyclic tetrazene from a bishydrazine, presumably with the help of a chelation of the substrate to the catalytic metal, which favored cyclization over oligomerization. Finally, the method could be used to prepare dissymmetric structures, albeit in the presence of an excess of one of the hydrazines.

Recent Advances in Catalytic Nitrogen–Nitrogen Bond Formation Reactions

“…The most widely used method for the synthesis of the novel structure tetrazenes involves oxidation from hydrazines with stoichiometric toxic/hazardous oxidants. Recently, catalytic aerobic oxidation of hydrazines into 2-tetrazenes was realized by a CuI catalyst together with a bipyridine ligand (Scheme ). Both aliphatic and aromatic hydrazines 205 proceeded well in this oxidation process.…”