Synthesis of Structurally Diverse Polycyclic Arenes Using Tandem Oxidative Ring Expansion Strategy

The impressive structural diversity of polycyclic arenes (PCAs) comprised of pentagon, hexagon, heptagon, and octagon rings has continued to drum up interest in the fields of synthetic chemistry and materials science owing to their tunable electronic properties in relation to their unique planar, twisted, and curved π-surface conformations. Although an array of synthetic strategies have been developed to construct both known and new PCA scaffolds in the past decades, flexible and expedient strategies for creating PCAs with differently sized rings embedded are rare. We describe herein our recent studies on the tandem oxidative ring expansion (TORE) strategy for the construction of structurally diverse PCAs involving intra- and intermolecular TORE reactions for hexagon-embedded PCAs, and intramolecular TORE reactions for O- or S-incorporated heptagon-embedded PCAs and octagon-embedded PCAs.