A pH‐Gated Photocage

Orthogonal control can be imposed on the photocleavage of a dioxinone heterocycle with the introduction of an amino substituent. Photoinduced electron transfer from this group to a naphthalene chromophore quenches the excited state responsible for the photochemical reaction. Protonation of the amino group prevents electron transfer and allows the cleavage of the dioxinone ring into a hydroxyester and a ketone.