Highly selective transfer hydrogenation of functionalised nitroarenes using cobalt-based nanocatalysts

Abstract

Anilines are important feedstock for the synthesis of a variety of chemicals such as dyes, pigments, pharmaceuticals and agrochemicals. The chemoselective catalytic reduction of nitro compounds represents the most important and prevalent process for the manufacture of functionalized anilines. Consequently, the development of selective catalysts for the reduction of nitro compounds in the presence of other reducible groups is a major challenge and is crucial. In this regard, herein we show that the cobalt oxide (Co₃O₄-NGr@C) based nano-materials, prepared by the pyrolysis of cobalt-phenanthroline complexes on carbon constitute highly selective catalysts for the transfer hydrogenation of nitroarenes to anilines using formic acid as a hydrogen source. Applying these catalysts, a series of structurally diverse and functionalized nitroarenes have been reduced to anilines with unprecedented chemo-selectivity tolerating halides, olefins, aldehyde, ketone, ester, amide and nitrile functionalities.