Site-selective iron-catalyzed C-H alkylation of pyrazinones, azauracils and quinoxalinones

Abstract

The direct C–H alkylation of nitrogen-containing heterocycles is a valuable and widely pursued transformation due to the importance of these scaffolds in pharmaceuticals and bioactive natural products. In this study, we report a general and efficient Fe(acac)₃/TBHP-catalyzed strategy for C(sp²)–H alkylation of a variety of N-heterocyclic frameworks, including pyrazinones and azauracils derivatives. Utilizing readily available ethers and aryl alkanes as alkylating agents, the protocol exhibits broad substrate scope, excellent tolerance to diverse functional groups, and practical scalability. Mechanistic studies, including radical scavenging experiments, suggest a radical-mediated path involved in the transformation.