Silver-catalyzed radical reaction of 2H-indazoles with 1,3-dicarbonyl compounds to access 3-dicarbonyl indazoles

Abstract

A convenient strategy for the direct synthesis of 3-substituted-2 H -indazole derivatives was developed in the presence of AgNO 3 /Na 2 S 2 O 8 under mild reaction conditions. The reaction affords a series of 1,3-dicarbonyl-2 H -indazoles products with yields of up to 82%. The mechanism of the strategy suggests that the reaction proceeds through a radical pathway. Moreover, this strategy provides a new protocol for the synthesis of functionalized 2 H -indazoles. • A direct synthesis of 3-substituted-2 H -indazole derivatives based on Ag(I)-peroxodisulfate system was developed. • This heterocyclic formation process features mild reaction conditions, simple execution and broad substrate scope. • Product will be further used directly to synthesize more structurally diverse polyheterocycles.