The Direct Synthesis of Imines, Benzimidazoles and Quinoxalines from Nitroarenes and Carbonyl Compounds by Selective Nitroarene Hydrogenation Employing a Reusable Iron Catalyst

The “replacement” of noble metals by earth abundant metals is a desirable aim in catalysis and a possible way of conserving rare elements. The “replacement” is especially attractive if novel selectivity patterns are observed permitting the development of novel coupling reactions. Herein, we report on a novel, robust and reusable iron catalyst, which permits the selective hydrogenation of nitroarenes in the presence of hydrogenation‐sensitive functional groups. Based on the selectivity pattern observed, the direct iron‐catalyzed synthesis of imines and benzimidazoles from nitroarenes and aldehydes becomes feasible. In addition, we introduce the direct synthesis of quinoxalines from nitroarenes and diketones applying our catalyst. A novel reusable iron catalyst has been introduced that is easy to synthesize and handle. Besides the selective hydrogenation of nitroarenes, the catalyst efficiently mediates the direct synthesis of imines, benzimidazoles and quinoxalines from nitroarenes and carbonyl compounds. Functional groups regarded as very hydrogenation‐sensitive can be tolerated.