N-Aryl Pyrrole Synthesis from Biomass-Derived Furans and Arylamine over Lewis Acidic Hf-Doped Mesoporous SBA-15 Catalyst

A mild and convenient method was developed to synthesize N-aryl pyrroles from biobased furans and arylamines over a Lewis acidic Hf catalyst for the first time. To demonstrate the broad utility and practical application of the method, several pyrrole-containing compounds with different functional groups were synthesized. Mechanistic studies indicated a direct nucleophilic attack of the amine on the furan ring, differing from the typical Paal–Knorr reaction depending on the 2,5-hexanedione intermediate. Finally, this method was successfully applied to the synthesis of an azo compound and a cyclooxygenase-2-selective inhibitor originating from biorenewable furans.