Nonaromatic compounds, containing oxygen

Nonaromatic Compounds Containing Oxygen, Nitrogen, or Sulfur... 

This chapter is one of the first attempts of systematic review of the synthetic methods and chemistry of nonaromatic saturated and unsaturated perfluorinated heterocycles. It summarizes data on the synthesis and chemical transformation of perfluorinated six- and to some extent five- membered nonaromatic heterocyclic compounds containing oxygen, nitrogen, sulfur, selenium, and phosphorous. It should be pointed out that the review is not all-inclusive one, but it is an attempt to provide representative examples of synthetic methods and chemistry of perfluorinated nonaromatic hetero-cychc materials. 

Silyl enol ethers are a class of electron-rich, nonaromatic compounds that easily form reactive radical cations on one electron oxidation. The silyl enol ether functional group is closely related to the carbonyl function and consequently, syntheses of silyl enol ethers generally make use of enolates. In addition, silyl enol ethers can be described as masked enols or enolates since their reactions often yield ketones. A number of oxidation reactions of silyl enol ethers making use of oxygen or oxygen-containing reagents such as peroxides, peracids (known as Rubottom oxidation), dioxirane, osmium tetraoxide, or triphenyl phosphite ozonide have been described in the literature. In all cases either a-hydroxy-ketones or the silyl enol ether epoxides are formed. 

Among the heterocyclic compounds, there are aromatic, e.g. pyridine, as well as nonaromatic, e.g. tetrahydrofuran, compounds. Similarly, there are saturated (e.g. tetrahydrofuran) and unsaturated (e.g. pyridine) heterocyclic compounds. Heterocycles also differ in their ring sizes, e.g. pyridine has a six-membered ring, whereas tetrahydrofuran is a five-membered oxygen-containing heterocyclic compound. 

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