Fig. 1: Representative examples for the synthesis of azoxy compounds.

a Oxidation of anilines into aromatic azoxy compounds. b Reduction of nitroarenes to aromatic azoxy compounds. c Hydrogenation of nitroarenes to aromatic azoxy compounds with noble metal catalyst in the presence of base. d This work: Direct hydrogenation of nitroarenes into aromatic azoxy compounds with non-noble metal catalysts under base-free and solvent-free conditions.