Palladium-Catalyzed Intramolecular Alkyne-Carbon Monoxide-Alkene Insertion Cascade for Synthesis of α-Methylenecyclopentenones

Article abstract of DOI:10.1021/jo00055a006

A method for the construction of α-methylenecyclopentenones fused to five-membered rings using a palladium catalyst is reported.The procedure involves the formation of ?-allylpalladium intermediates that undergo sequential intramolecular alkyne insertion, carbon monoxide insertion, intramolecular alkene insertion, and β-hydride elimination.Examples of the cyclization are seen in eq 2 and Scheme III.