Indium-mediated one-pot pyrrole synthesis from nitrobenzenes and 1,4-diketones

One-pot reduction-triggered heterocyclizations of nitrobenzene derivatives with 1,4-diketones were investigated. In the presence of indium/AcOH in toluene at 80 °C, reaction of nitrobenzenes with 2,5-hexadione produced moderate to excellent yields (40-98%) of the corresponding pyrroles within 1.5-24 h depending on the substituents of the starting materials. Similarly, the reaction of nitrobenzenes with 1-phenyl-1,4-pantanedione in the presence of indium/AcOH in toluene at reflux afforded the corresponding pyrroles within 0.5-24 h with 60-98% yields.