One‐Step Synthesis of Benzotetra‐ and Benzopentacyclic Compounds through Intramolecular [2+3] Photocycloaddition of Alkenes to Naphthalene

Rings from light: Irradiation of acetonitrile solutions containing 1-cyano-2-(4-pentenyl)naphthalene derivatives afforded benzotetra- and benzopentacyclic compounds with tri- and tetraquinane skeletons in high yields, through intramolecular [2+3] photocycloaddition of the alkene at the 2,4-positions of the cyanonaphthalene (see scheme; n=1, 2). The structures of these adducts were confirmed by their spectral properties and by X-ray crystallographic analyses.