Cobalt nitride enabled benzimidazoles production from furyl/aryl bio-alcohols and o-nitroanilines without an external H-source

Benzimidazole derivatives have wide-spectrum biological activities and pharmacological effects,but remain challenging to be produced from biomass feedstocks.Here,we report a green hydrogen transfer strategy for the efficient one-pot production of benzimidazoles from a wide range of bio-alcohols and o-nitroanilines enabled by cobalt nitride species on hierarchically porous and recyclable nitrogen-doped carbon catalysts(Co/CN_(x)-T,T denotes the pyrolysis temperature)without using an external hydrogen source and base additive.Among the tested catalysts,Co/CN_(x)-700 exhibited superior catalytic performance,furnishing 2-substituted benzimidazoles in 65%–92%yields.Detailed mechanistic studies manifest that the coordination between Co^(2+)and N with appropriate electronic state on the porous nitrogen-doped carbon having structural defects,as well as the remarkable synergetic effect of Co/N dual sites contribute to the pronounced activity of Co/CN_(x)-700,while too high pyrolysis temperature may cause the breakage of the catalyst Co-N bond to lower down its activity.Also,it is revealed that the initial dehydrogenation of bio-alcohol and the subsequent cyclodehydrogenation are closely correlated with the hydrogenation of nitro groups.The catalytic hydrogen transfer-coupling protocol opens a new avenue for the synthesis of N-heterocyclic compounds from biomass.