K 2 S 2 O 8 -Mediated Radical Cyclization of 1,6-Enyne for the Synthesis of Diiodonated γ-Lactams.

A novel and convenient K 2 S 2 O 8 -mediated diiodo cyclization of 1,6-enynes for the facile synthesis of functionalized γ-lactam derivatives has been developed. This reaction features mild and transition-metal-free conditions, which offer a green and efficient entry to synthetically important γ-lactam scaffolds. Mechanistic studies suggest that iodide radicals initiate the cascade cyclic transformation.