Lewis acid-promoted tandem desulfurization and hydroxylation of γ-phenylthio-substituted lactams: novel synthetic strategy of isoindolobenzazepine alkaloid, chilenine

Treatment of a variety of alicyclic and aromatic γ-phenylthio-substituted lactams with Lewis acids such as cuprous or cupric halides in aqueous solution at rt was found to undergo novel tandem desulfurization and hydroxylation reactions to generate γ-hydroxylated lactams without the ring-opened products in extremely high yields, respectively. This process was further applied to the total synthesis of an isoindolobenzazepine alkaloid, chilenine, by featuring the elaboration of the functionalized phthalimide derivative.