Breaking binary competitive adsorption in the domino synthesis of pyrroles from furan alcohols and nitroarenes over metal phosphide

Abstract

Herein, an efficient domino synthesis for N-aryl pyrroles and tetrahydropyrroles from biomass-derived furan alcohols (i.e., 5-methyl furfuryl alcohol, and 2,5-bis(hydroxymethyl)furan) and nitrobenzenes was reported for the first time over metal phosphides. Dual active sites, including metal sites for nitro hydrogenation, acid sites for furan alcohol ring-opening determine the catalytic performance. Different from traditional tandem catalysts of Pd/C and HZSM-5 or Amberlyst-15 that suffer from binary competitive adsorption of furan and nitro groups on metal sites, as well as hydroxyl and hydrogenated amino groups on the acidic sites, metal phosphides show unexpected cooperative catalytic properties with the oriented synthesis of pyrroles over NiCoP and tetrahydropyrroles over Ni2P. Furthermore, the catalyst displays outstanding stability and recycling performance after 4 runs. This work demonstrates an effective strategy for governing reaction routes by selective activation and shows the powerful synergistic effect of hydrogenation and acid catalysis.