Indium(III)-catalyzed synthesis of N-substituted pyrroles under solvent-free conditions

A variety of N-substituted pyrroles have been synthesized by reacting gamma-diketones ((RC)-C-1(O) CH2CH2C(O)R-2 : R-1, R-2 = Me, Ph) with amines (RNH2 : R=Alkyl, Aryl, TsNH) or diamines (1,6-diaminohexane and 1,2-diaminoethane) in the presence of indium tribromide, indium trichloride or indium trifluoromethanesulfonate at room temperature under solvent-free conditions. The experiment protocol features simple operations, and the products are isolated in high to excellent yields (81-98%).