Catalytic Photoredox C–H Arylation of 4-Oxo-4<i>H</i>-pyrido[1,2-<i>a</i>]pyrimidine-3-diazonium Tetrafluoroborates and Related Heteroaryl Diazonium Salts
Kris Antolinc, Helena Brodnik, Uroš Grošelj, Bogdan Štefane, Nejc Petek, Jurij Svete
Abstract
High Resolution Image Download MS PowerPoint Slide Irradiation of mixtures of title diazonium salts and heteroarenes with green light (510 nm) in the presence of eosin Y disodium salt ( EY-Na 2 ) as a photocatalyst furnished the corresponding arylation products in 8–63% yields. The proposed photocatalytic cycle is analogous to that proposed previously for closely related photoredox C–H arylations with aryl diazonium salts as aryl radical sources. This method has a broad substrate scope and represents a metal-free alternative for the synthesis of 3-heteroaryl-substituted 4 H -quinolizin-4-ones and azino- and azolo-fused pyrimidones with a bridgehead nitrogen atom.