Oxidative ring opening reactions of a-hydroxy ketones

Aybey, Ayşe
Chiral polyfunctionalized 1,5-dicarbonyl compounds are important synthetic intermediates and starting materials for many biologically active compounds so their synthesis has a great importance in the literature. In the first step, 1,3-cyclohexandione and other b-diketone derivatives are protected under acid catalyzation and their corresponding b-keto enol ether derivatives are obtained. These b-keto enol ethers are then converted to a-acetoxy enones in racemic form by Mn(OAc)3 mediated oxidation. Enzymatic kinetic resolution is applied to the racemic acetoxy enones by using different lipases and enantiomerically pure a-acetoxy and hydroxy enones are obtained. Then, dicarbonyl derivatives are obtained by hydrolizing racemic a-acetoxy enones. Oxidative cleavage of racemic a-acetoxy diketones in the presence of oxone gives corresponding racemic 1,5-dimethyl ester derivatives. By using this reaction as a reference, same reactions are applied to the chiral a-acetoxy and hydroxy diketones in order to synthesize chiral a-acetoxy and hydroxy 1,5-diester derivatives.


Chemoenzymatic functionalization of cyclic 1,2-diketones
Biçer, Işıl; Akkaya, Engin Umut; Department of Chemistry (2006)
Chiral hydroxylated cyclopentane derivatives are important structural units in many biologically active compounds and are also important synthons for the asymmetric synthesis of natural products. Synthesis of these types of compounds in optically pure form found increased interest in pharmaceutical chemistry. For this purpose 5-acetoxy-3-methyl-2-methoxy-2-cyclopentene-1-one and 5-acetoxy-3-ethyl-2-methoxy-2-cyclopentene-1-one were acetoxylated using manganese (III) acetate at a’ positions. Enzyme catalyzed...
Synthesis of chiral lactones via the baeyer villiger oxidation of cyclic aromatic acetoxy ketones novel annulation reactions of 2-propynyl-1,3-dicarbonyl compounds to form pyrroles addition of acyl phosphonates to diethyl cyanophosphonate (depc)
Aybey, Asuman; Demir, Ayhan Sıtkı; Department of Chemistry (2009)
Chiral Baeyer-Villiger (BV) oxidation of cyclic ketones allows rapid access to asymmetric lactones as valuable intermediates in organic chemistry and frequently encountered precursors in enantioselective synthesis. In the first part, BV oxidation of functionalized ketones, especially cyclic -hydroxy and acetoxy ketones is described which could be a straightforward route to the -hydroxy lactones and -hydroxyalkanoic acid derivatives. The -acetoxylation of indanone, tetralone and chromanone derivatives by usi...
Synthesis of ferrocenyl cycloheptadienones
Açıkgöz, Canet; Zora, Metin; Department of Chemistry (2005)
Synthesis of seven-membered ring systems such as cycloheptadienones has attracted a great deal of attention in organic chemistry since they are present in a variety of biologically important molecules. Incorporation of the essential structures of such compounds with a ferrocene moiety instead of an aryl group could provide subtances with enhanced antitumor activities since some ferrocene derivatives have already proved to be active against a number of tumors. To develop a ferrocenyl-substituted seven-member...
Stereoselective synthesis of cyclopentanoids and cyclitol derivatives originated from polychlorinated norbornene systems
Gümüş, Ayşegül; Tanyeli, Cihangir; Department of Chemistry (2009)
Optically active polychlorinated norbornene systems are important starting compounds for the synthesis of many complex molecules. The synthetic strategy of this study mainly depends upon the enzymatic resolution of hydroxymethyl-substituted polychlorinated norbornene structures. The enantiomerically enriched acetoxymethyl derivatives were synthesized in high ee values by several lipases. The absolute configuration of tetrachlorinated norbornene system was determined by X-ray analysis. The second part of the...
Chemoenzymatic synthesis of chiral hydroxymethyl cycloalkenols
Şenocak, Deniz; Demir, Ayhan Sıtkı; Department of Chemistry (2004)
Chiral cyclic alkenols with hydroxymethyl functionality are important structural units in many biologically active natural compouds such as prostaglandins, sesquiterpene antiviral agents, pentenomycins, xanthocidin, sarkomycin, etc. 1,3-cycloalkanediones are converted into bicyclic polyoxo derivatives with formaldehyde and trioxane in the presence of Lewis acid. Selective oxidation of the bicyclic compounds by using manganese(III)acetate followed by enzyme-catalyzed kinetic resolution afforded chiral bicycl...
Citation Formats
A. Aybey, “Oxidative ring opening reactions of a-hydroxy ketones,” M.S. - Master of Science, Middle East Technical University, 2008.