Metal-Free Radical Oxidative Cyclization of o-Azidoaryl Acetylenic Ketones with Sulfinic Acids To Access Sulfone-Containing 4-Quinolones.

A novel one-pot synthesis of sulfone-containing 4-quinolones with easily available sulfinic acids as sulfonylating precursors is described. This reaction is characterized by mild reaction conditions, high functional-group tolerance and amenability to gram-scale synthesis.