Four‐membered cyclic peroxides: Carriers of chemical energy

Abstract

AbstractFour‐membered cyclic peroxides are high‐energy compounds often associated to cold light emission, but whose chemical and biological roles are still matters of debate. The often‐dangerous synthesis of 1,2‐dioxetanes, achieved around 50 years ago, has been mastered over the years to a point where some derivatives are commercially available. This fact does not imply that 1,2‐dioxetanes can be conveniently prepared in the gram scale or that the synthesis of analogous 1,2‐dioxetanones and the elusive 1,2‐dioxetanedione are simple. Important questions on the mechanism of chemiluminescence and bioluminescence reactions are under experimental and theoretical scrutiny. The available data have contributed to relate structural and medium effects to the quantum efficiency of these compounds to produce excited states. Consequently, such peroxides have been suggested to produce biologically relevant electronically excited species in vivo in the absence of light. The connection of this hypothesis with melanin‐mediated photodamage in the dark has renewed the interest in such cyclic peroxides. This review gives some insight on the synthesis, chemiluminescence mechanism, and biological relevance of 1,2‐dioxetanes, 1,2‐dioxetanones, and 1,2‐dioxetanedione and provides practical protocols for those interested in engaging this field.