Reductive Acylation of Azobenzene

Abstract

Considerable attention has been focused onto the fixation of molecular nitrogen in recent years.¹ As the in vivo process is catalyzed by the enzyme nitrogenase which consists of two protein components: an Fe-protein and an Fe-Mo-protein, the redox reaction must occur in the immediate vicinities of the metal cluster and is likely preceded by coordination of N₂ with one of the molybdenum atoms. Our interest in the organic prototype of the reaction, namely the saturation and cleavage of NN multiple bonds, has resulted in a report of reducing azobenzenes to anilines by the Pd-catalyzed hydrogen transfer from cyclohexene.₂ We now wish to describe the use of Mo(II) species in carboxylic acids to effect the conversion of azobenzene to anilides.