Formation of a new benzotriquinane skeleton via intramolecular photocycloaddition reactions of a phenylethynes moiety to a 1-cyanonaphthalene ring system.

Photoirradiation of 1-cyano-2-(2,2-dicyano-5-phenylpentyn-4-yl)naphthalene and its analogues promotes sequential intramolecular [2π + 2π] photocycloaddition and cyclobutene ring opening to form benzocyclooctatetraenes, which are then transformed to benzotriquinanes in good yields via a photochemical transannular cyclization process.