Nickel‐Catalyzed Selective Hydrazoarenes and Aminoarenes Formation from Azoarenes Using Ammonia–Borane

Abstract Herein, we report the synthesis of an air‐stable, phosphine‐free NNN‐based nickel(II) pincer complex that catalyzed the generation of diverse hydrogenated products from azoarenes using ammonia borane (AB) as a transfer hydrogenating source, facilitating at room temperature. The synthetic protocol tolerates the transfer hydrogenation (TH) of various azo‐derived substrates, especially bearing reducible functional groups. The preliminary mechanistic investigation studies revealed the crucial role of nickel catalyst in the TH of the azo‐substrates using AB and ethanol, which generates the boron‐alkoxide by‐products. The significant advantage of this study highlights the utilization of nickel catalyst for the complete N═N cleavage of azoarenes to generate aminoarenes, assisted at base‐free, mild reaction conditions.