Heterocyclic compounds reactions with singlet oxygen

The Reactions of Diazoacetic Esters with Alkenes, Alkynes, Heterocyclic and Aromatic Compounds V. Dave and E. W. Warnhoff, Org. React., 1970,18, 217-402. Reactions of Singlet Oxygen with Heterocyclic Systems H. H. Wasserman and B. H. Lipshutz, Org. Chem., 1970, 40, 429-509. 

Reviews on the following aspects of four-membered heterocycles have appeared 1,2-dioxetans and the reaction of singlet oxygen with alkenes/ /8-lactam antibiotics, small ring compounds of sulphur and selenium," recent developments in the synthesis of azetidines, the chemistry of benzazetes and of thiacyclobutenes (thietes) and their valence tautomers, and conformational barriers and interconversion pathways in some small ring systems. ... 

The versatility of these [4+2] heterocyclization reactions is a consequence of the wide range of ene and diene components which can be used. In addition to alkenes and alkynes functioning as ene components, a variety of heterodienophiles is available such as electron-deficient imines (e.g. equation 89), nitriles e.g. equation 90), electrophilic carbonyl compounds (e.g. equation 91), thiocarbonyl compounds (e.g. equation 92), singlet oxygen (e.g. equation 93), nitroso compounds (e.g. equation 94), sulfenylsulfonamides (e.g. equation 95) and azo compounds (e.g. equation 96). Many of these reactions proceed with excellent regioselectivity and stereoselectivity, probably because in many instances they involve... 

Alcohols (as well as amines, sulfides and many hydrocarbons) may act as overall hydride donors towards excited nonbonding-rr " states of carbonyl compounds and heterocycles. The synthetic as well as the photophysical aspects of these processes have been discussed extensively. These reactions will not be dealt with further here. Singlet oxygen also accepts hydride from alkoxides in the gas phase the mechanisms of such reactions have received considerable study. ... 

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