Accessing Molecular Complexity from Methane and Other Gaseous Alkanes via Photocatalytic Cascade Cyclization

The direct transformation of simple and abundant feedstocks into structurally complex molecules remains a central challenge in modern organic synthesis. Herein, we report a method for the oxidative cascade cyclization of N-aryl and N-benzoyl acrylamide derivatives, promoted by methane and other gaseous alkanes. This transformation is enabled by a readily available iron catalyst in combination with N-fluorobenzenesulfonimide (NFSI) as the oxidant, proceeding under mild conditions to afford a diverse array of N-heterocyclic frameworks in high yields. Late-stage functionalization studies highlight the utility of methane in the synthesis of biologically relevant scaffolds. Moreover, the Fe/NFSI system facilitates a radical sampling regime that enables the selective functionalization of less reactive primary C─H bonds. Overall, this work establishes a sustainable and versatile platform for constructing molecular complexity directly from gaseous alkanes.