Internal Amide-Triggered Cycloaromatization of Maduropeptin-Like Nine-Membered Enediyne.

In the Masamune–Bergman cyclization of a nine-membered non-conjugated enediyne with an internal, maduropeptin-like nucleophile, the exocyclic alkene migrated to form the nine-membered conjugated enediyne, triggered by the intramolecular addition of the amide group; final aromatized products showed up to 85% yield.