Homogenous Iron-Catalysed hydrogenation of polar substrates with precise chemoselectivity

Hydrogenation of different types of unsaturated substrates with a single catalyst has always been a challenge for transition-metal-based catalysts. In this paper, an iron tetraphosphine complex shows high catalytic efficiency for selective hydrogenation of aldehydes, conjugated ketones and nitroarenes in the presence of other easily reduced functional groups like ketone, alkenyl, ester and alkynyl groups. The catalytic efficiency, chemoselectivity and robustness of this Fe/P^2C‑PPh22N^Bn2 catalyst found its merit in the preparation of several important drug intermediates. A diamagnetic trans-iron dihydride complex formed under the reaction conditions was supposed to be an on-cycle catalytically active species. We are looking forward to the application of this method in pharmaceutical and fine chemical industries.