Divergent Synthesis of α-Aroyloxy Ketones and Indenones: A Controlled Domino Radical Reaction for Di- and Trifunctionalization of Alkynes.

Three different modes of aldehyde/alkyne assembly through a controlled radical reaction are devised. While a double C-H activation/annulation leads to indenones, a concurrent oxidation of both aldehydes and alkynes in the course of their connection offers aroyloxy ketones. Besides two types of cascade reactions starting from identical materials, through a phenylpropiolic acid substrate, a cascade three C-C bond formation via an uninterrupted C-H functionalization/annulation/decarboxylative aroylation as a formidable challenge in radical reactions occurs to deliver 2-aroyl-3-aryl indenones.