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In the decade that ensued, selenium-mediated oxidation rapidly expanded in use, and in 1939, Andre Guillemonat and co-workers disclosed the selenium dioxide-mediated oxidation of olefins at the allylic position. [2] Today, selenium-dioxide-mediated oxidation of methylene groups to alpha ketones and at the allylic position of olefins is known as ...
The selenium starting material is reduced to selenium, and precipitates as a red amorphous solid which can easily be filtered off. [10] This type of reaction is called a Riley oxidation. It is also renowned as a reagent for allylic oxidation, [11] a reaction that entails the following conversion Allylic oxidation. This can be described more ...
Selenium dioxide oxidation In terms of reaction mechanism , SeO 2 and the allylic substrate react via pericyclic process beginning with an ene reaction that activates the C−H bond. The second step is a [2,3] sigmatropic reaction .
Allyl alcohols in general are prepared by allylic oxidation of allyl compounds, using selenium dioxide or organic peroxides. Other methods include carbon-carbon bond-forming reactions such as the Prins reaction, the Morita-Baylis-Hillman reaction, or a variant of the Ramberg-Bäcklund reaction. Hydrogenation of enones is another route.
The conversion of valencene to nootkatone is an example of allylic oxidation. In the synthesis of some fine chemicals, selenium dioxide is used to convert alkenes to allylic alcohols: [15] R 2 C=CR'-CHR" 2 + [O] → R 2 C=CR'-C(OH)R" 2. where R, R', R" may be alkyl or aryl substituents.
Selenium disulfide has been used in shampoo as an antidandruff agent, an inhibitor in polymer chemistry, a glass dye, and a reducing agent in fireworks. [6] Selenium trioxide may be synthesized by dehydrating selenic acid, H 2 SeO 4, which is itself produced by the oxidation of selenium dioxide with hydrogen peroxide: [8]
Industrial production of selenium usually involves the extraction of selenium dioxide from residues obtained during the purification of copper. Common production from the residue then begins by oxidation with sodium carbonate to produce selenium dioxide, which is mixed with water and acidified to form selenous acid (oxidation step).
Selenium oxide may refer to either of the following compounds: Selenium dioxide, SeO 2; Selenium trioxide, SeO 3; Diselenium pentoxide, Se 2 O 5