Dimerization–cyclization reactions of isocyanoaryl-tethered alkylidenecyclobutanes via a triplet biradical mediated process

Abstract

A triplet biradical mediated dimerization–cyclization reaction of isocyanoaryl-tethered alkylidenecyclobutanes has been reported in this paper, giving a new protocol for the construction of macrocyclic skeletons including dihydroquinoline and quinoline units in moderate yields. The reaction proceeded through a key 1,4-diazabutatriene intermediate along with intramolecular redox to produce a biradical intermediate species, which subsequently experienced bond-breaking and -making processes to give the desired product. The reaction mechanism was supported by density functional theory (DFT) calculations.