Annulative π-extension (APEX) reactions for precise synthesis of poly cyclic aromatic compounds

Polycyclic aromatic compounds are recognized as highly important class of compounds in materials science due to their high utility as organic semiconductors and organic optoelectronic materials. In general, they can be obtained through the established π-extension methods from unfunctionalized aromatics, while the syntheses are often suffered from multi-step process including halogenation, coupling reaction, Diels-Alder reaction, aromatization and so on. Recently, we have established a novel synthetic concept "annulative π-extension (APEX)" which has the potential to have a tremendous impact on the fields of synthetic chemistry since it allows rapid access to fused aromatic systems from simple unfunctionalized aromatic compounds in a single step. Here we report our recent results of palladium-catalyzed APEX reactions for the synthesis of polycyclic aromatic hydrocarbons, polycyclic heteroaromatics, nanographenes and even graphene nanoribbons from readily available unfunctionalized aromatics. © 2020 Society of Synthetic Organic Chemistry. All rights reserved.