Phenolic spiroadamantyl-substituted dioxetanes are well known base-induced chemiluminescent compounds. Fast-atom bombardment collision-induced dissociation tandem mass spectrometry (FAB CID-MS/MS) of five phenolic spiroadamantyl-substituted dioxetanes in the negative-ion mode clearly showed that a highly efficient cleavage of the dioxetane rings took place to produce the corresponding phenolate ion almost exclusively. The mass spectrometric behavior of these compounds reflects the highly efficient intramolecular electron-transfer-induced cleavage of dioxetane rings, which participates in the highly efficient base-triggered chemiluminescent reactions of these compounds in solution.
