Syntheses and Reactivity of Naphthalenyl-Substituted Arenediynes

A series of naphthalenyl-substituted arenediynes were prepared to examine photochemical reactivity. For naphthalen-1-ylethynyl arenediyne, 350 nm photolysis resulted in a tandem [2 + 2] photocycloaddition to afford cyclobutene adducts. For naphthalen-2-ylethynyl derivatives, electron-donating methoxy substituents were found to facilitate C1–C6 Bergman cyclization at 300 nm. Theoretical calculations provided further insight into thermal and photochemical reactivity.