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.

We describe the development of a new method for construction of highly substituted indole scaffolds through the strategic utilizing of the metathesis of Ar-X σ-bonds based on the dynamic nature of palladium-based oxidative addition/reductive elimination. A suitable and simple catalytic system has provided an appropriate platform for a productive ligand exchange and consecutive carbopalladation/C–H activation/amination of phosphine ligands with alkynes and aromatic/aliphatic amines for construction of structurally diverse indoles.