The fit three-membered ring substituted spiro-l, 2-dioxetane (2) has been synthesized and characterized through the singlet oxygenation of methyleneaziridine 1. Thermodynamic properties of the decomposition of 2 are as follows: kzOOc= 11.5 s-'; E,= 18.3 kcal/mol; AH*= 17.9 kcal/mol; AS*= 7.5 eu. The chemical properties of this novel dioxetane are compared to those of dioxetanes 11 and 12, dioxetanimine 9, and dioxetanone 10.
