K2S2O8-mediated acylarylation of unactivated alkenes via acyl radical addition/C–H annulation cascade of N-allyl-indoles with silver cocatalysis

A silver-catalyzed, K2S2O8-mediated protocol to access regioselective acylarylation of unactivated alkenes was developed. The reaction between N-allyl-indoles and α-oxocarboxylic acids proceeded smoothly and involved an acyl radical addition/C–H cyclization cascade. The protocol showed a broad substrate scope and good tolerance of functional groups. The reaction proceeded with both internal and terminal alkenes to furnish many functional pyrrolo[1,2-a]indoles bearing the ketone carbonyl group, and this feature also provides the potential to construct structurally complex N-containing heterocycles.