Four‐Membered Ring Peroxides as Excited State Equivalents: A New Dimension in Bioorganic Chemistry

Consideration of chemiluminescent and bioluminescent processes invariably brings to mind the four‐membered ring peroxides, 1,2‐dioxetanes and α‐peroxylactones. Nevertheless, while chemiluminescence and bioluminescence are well established fields of scientific study, isolable and characterized “high‐energy” molecules such as the 1,2‐dioxetanes and α‐peroxylactones are of relatively recent vintage, about a decade. These intriguing compounds produce electronically excited products which manifest themselves by light emission during their thermal decay; more importantly, these transformations are involved in luminescent as well as dark enzymatic processes. It is not our intention to present a comprehensive overview in this progress report, but rather to focus on those aspects which require further study.