Copper-catalyzed C5-regioselective C[sbnd]H sulfonylation of 8-aminoquinoline amides with aryl sulfonyl chlorides

Abstract

Copper-catalyzed CH sulfonylation of 8-aminoquinoline scaffolds in the unusual C5 position was developed. The protocol using inexpensive CuI as the catalyst and commercially available aryl sulfonyl chlorides as the sulfonylation reagents, shows broad substrate scope, producing moderate to good yield of sulfone. The developed method was conveniently applied to synthesize a potential fluorinated PET radioligand of 5-HT6 serotoninergic receptor. Moreover, mechanistic studies revealed that the reactions underwent a radical process.