Organic Chemistry
The chemistry of singlet oxygen is different from that of ground state oxygen. For example, singlet oxygen can participate in Diels-Alder and cycloaddition reactions, ene reactions, and heteroatom (S, Se, P, N) and organometallic complex oxidation reactions. Singlet oxygen reacts with an alkene -C=C-CH- by abstraction of the allylic proton in an ene reaction type reaction to the allyl hydroperoxide HO-O-R (R = alkyl), which can then be reduced to the allyl alcohol. (This reaction is not actually a true ene reaction, because it isn't concerted: singlet oxygen forms an exciplex that can be called an "epoxide oxide", which then abstracts the hydrogen.) An example is an oxygenation of citronellol:
With some substrates 1,2-dioxetanes are formed and cyclic dienes such as 1,3-cyclohexadiene form cycloaddition adducts. With water trioxidane, an unusual molecule with three consecutive linked oxygen atoms, is formed.
Read more about this topic: Singlet Oxygen
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