Unsupported nanoporous platinum catalyst for the chemoselective hydrogenation of imines and reductive amination of benzaldehydes and anilines

The development of efficient heterogeneous catalysts for selective hydrogenation imines and reductive amination remains highly desirable in synthetic chemistry. Herein, we report a high-performance unsupported nanoporous platinum (PtNPore) catalyst for the chemoselective hydrogenation of imines and reductive amination of benzaldehydes with anilines, affording the corresponding secondary amines in good to excellent yields. Notably, the PtNPore catalyst exhibits remarkable chemoselectivity, preserving sensitive functional groups such as Cl and Br under the reaction conditions. Furthermore, the system demonstrates broad applicability, successfully enabling the N-alkylation of nitrobenzene with aldehydes to deliver secondary amines in high yield. The unsupported PtNPore can be reusable at least four times without obvious loss of catalytic activity. This work highlights the potential of unsupported nanoporous metals as robust and selective catalysts for sustainable amine synthesis.