Novel Way of Generating Singlet Oxygen

Singlet oxygen is a powerful but selective oxidant which would be used more but for the fact that it requires photochemistry to generate it. Now French chemists have come up with an alternative way to generate it. Calcium peroxide diperoxohydrate (CaO₂•2H₂O₂) can easily be generated from calcium peroxide octahydrate and 50% aqueous hydrogen peroxide. The resultant product is not stable at room temperature but is stable for several days at –80°C (Pierlot C et al, J Org Chem, 2002, 67, 2418) and releases singlet oxygen in 25% yield.

The oxygen can be used in the same way as if generated photochemically, i.e. for cycloadditions, ene reactions etc.

I would advise safety precautions and more safety testing before carrying out the reagent preparation on a large scale.