ABSTRACT
Photochemical valence isomerization involving the intramolecular (2 + 2)-cycloaddition that converts bicyclo[2.2.1]hepta-2,5-diene
(norbornadiene, N) to tetracyclo[3.2.0.0.
]heptane
(quadricyclane, Q) has been the subject of much investigation from a mechanistic point of view.
