Ring-Opening Cyclization of Alkylidenecyclopropyl Ketones with Amines. An Efficient Synthesis of 2,3,4-Trisubstituted Pyrroles

An efficient synthesis of 2,3,4-trisubstituted pyrroles via intermolecular cyclization of alkylidenecyclopropyl ketones with amines was observed. The addition of anhydrous MgSO₄ improved the yields of the products 3. A possible mechanism involving the distal cleavage of the C−C bond of cyclopropane ring was proposed.