SPONTANEOUS OXYGENATION OF CYCLIC OLEFINS - EFFECTS OF STRAIN

Reactivity of strained olefins 1-3, 41, and 44 toward spontaneous oxygenation has been evaluated. Angle-strained olefins 1, 32, and 35 react spontaneously with ground-state triplet oxygen, at room temperature, to yield quantitatively, not copolymers or hydroperoxides, but epoxides and diketones in approximately a 2:1 ratio. The autoxidation of 1 is carried out with various solvents, inhibitors, initiators, and in the presence of 2 and 1,2-dimethylcyclohexene to determine the mechanistic details. Compared with 1, autoxidation of 2 and 3 follows a different route yielding mainly hydroperoxides along with other products. The mechanism of the spontaneous autoxidation is discussed in light of these results.