Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

1 Wiadomości Chemiczne

1 2001

Znaleziono wyników: 1

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Związki selenu jako odczynniki i katalizatory w reakcjach utleniania związków organicznych

100%

Młochowski J. , Brząszcz M. , Giurg M. , Wójtowicz H.

tom [Z] 55, 1-2

9-44

Oxidation reactions are fundamental processes widely applied in organic synthesis. Among many reagents used in these reactions, elemental selenium and particularly some of its compounds have been reported as effective and selective oxidants and catalysts for the oxidation of various organic substrates. One of them is selenium(IV) oxide, easily available regent for hydroxylation of activated a-positions particularly at allylic and propargylic sites. It also can introduce carbonyl functionality at activated positions. Used in combination with hydrogen peroxide or t-butylhydroperoxide it acts as oxygen-transfer agent. Both of these hydroperoxides can be used in the presence of seleniumu(IV) oxide for epoxidation, 1,2-dihydroxylation and a-carbonylation of alkenes, for oxidation of aldehydes into carboxylic acids, sulfides to sulfoxides or sulfones, secondary amines to nitrones and for other reactions. Benzeneseleninic acid, other areneseleninic acids and their anhydrides are known as stoichiometric oxidants or activators of other oxygen donors. They have been successfully applied for oxidation of many organic compouns, among them alkenes, alcohols, phenols, amines, hydrazones, sulfides, 1,3-dithiolanes and azines. Organic diselenides, the precursors of seleninic acids, have been used as oxygen-transfer catalysts for oxidation of various functional groups with hydrogen peroxide, t-butylhydroperoxide and other oxygen donors , while dimethyl and diphenyl selenoxides are efficient stoichiometric oxidants (e.g. for conversion of halomethyl or hydroxymethyl group into formyl group]. Most recently, selenenamides, particularly 2-phenyl-1,2-benzisoselenazol-3(2H)-one (ebselen) and its analogous were found as efficient catalysts for hydrogen peroxide and tbutylhydroperoxide oxofunctionalization of olefins, oxidation of azomethine compounds and sulfides.