Catalytic Aerobic Oxidation of Hydrazines into 2-Tetrazenes

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 bis-hydrazine, 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.

Automated summary

In this study, a catalytic formation of 2-tetrazenes was reported, which involved the copper (ii) promoted oxidation of hydrazines in the presence of bipyridine ligands using air or dioxygen as the terminal oxidant. The method successfully produced symmetrical tetrazenes, which were previously prepared using toxic or stoichiometric oxidants. Additionally, the catalytic reaction could be used for the formation of cyclic tetrazenes and dissymmetric structures under certain conditions.