Silver-promoted regioselective [4+2] annulation reaction of indoles with alkenes to construct dihydropyrimidoindolone scaffolds†
An AgI-promoted regioselective [4+2] annulation reaction of indoles with alkenes has been established. During the transformation, N-centered radicals are generated by the oxidation of the N–H bond of N-alkoxyamides. Control experiments and DFT calculations reveal a plausible mechanism. This synergistic process achieves the direct construction of new C–C and C–N bonds under relatively mild conditions with broad substrate scope, high atom economy, and easy-to-handle nature.