Palladium-catalyzed ortho-acyloxylation of 2-aryl-4H-pyrido[1,2-a]pyrimidin-4-ones: synthesis of benzo[b]furano-pyridopyrimidinones

Abstract

Herein, a chelation-assisted palladium-catalyzed ortho-acyloxylation of 2-aryl-4H-pyrido[1,2-a]pyrimidin-4-ones is reported for further elaboration. Carboxylic acid together with phenyl iodoacetate (PhI(OAc)₂) was used as the acyloxylation source in the substrate-directed C–H functionalization. The ortho-acyloxylated 2-aryl 3-bromo pyridopyrimidinones were transformed to benzofuran-fused pyridopyrimidinones via base-mediated easy hydrolysis, followed by intramolecular ring closure.