Environmentally Friendly Synthesis of Polysubstituted Pyrroles in Ionic Liquid via Gold-Catalyzed Propargylic Substitution/Hydration/Amination/Cycloisomerization Sequence.

An environmentally friendly synthesis of polysubstituted pyrroles in ionic liquid was achieved via a gold-catalyzed propargylic substitution/hydration/amination/cycloisomerization sequence. Treatment of propargylic alcohols, 1,3-dicarbonyl compounds, and arylamines in the presence of AuBr3 (5 mol%) and AgOTf (15 mol%) in [EMIM][NTf2] afforded polysubstituted pyrroles in good to high yield. This reaction involves reacting arylamine with the hydrated propargylic substitution product formed as an intermediate to yield polysubstituted pyrroles.