Nucleophilic O-Transfer, Cyclizaton, and Decarboxylation of Carbonyl Oxide Intermediate in the Reaction of Stable Imidazolylidene and Singlet Oxygen

The 1O2 oxidation of 1,3-dialkylimidazol-2-ylidene (alkyl=tert-butyl) resulted in the formation of a carbonyl oxide intermediate which was shown to react as a nucleophilic O-transer and to cyclize to an unstable dioxirane intermediate leading to, as final products, bis-imine RN=CH–CH=NR and carbene-CO2 adduct.