Gold(I)-Catalyzed Cyclization of β-Allenylhydrazones: An Efficient Synthesis of Multisubstituted N-Aminopyrroles

The gold(I)-catalyzed cycloisomerization of beta-allenylhydrazones provides an efficient access to multisubstituted N-aminopyrroles, which are obtained in good to excellent yields. This new intramolecular cyclization method can be applied either to alkyl- or aryl-substituted allenes. The reaction proceeds under mild conditions with short reaction times through a selective intramolecular 1,2-alkyl or -aryl migration extending the general scope of the reaction.