Cycloalkanones Cyclohexanones, Cyclopentanones

The kinetics of the potassium hexacyanoferrate(III)-catalysed oxidation of glucose with ammonium peroxodisulfate have been studied.82 The kinetics and mechanism of oxidation of some cycloalkanols by alkaline Fe(CN) have been reported.83 The same group has also studied the oxidation of cycloalkanones under comparable conditions and determined the order of reactivity as cyclohexanone > cyclopentanone > cyclo-octanone > cycloheptanone.84 Palladium(II) has been found to catalyse the oxidation of formaldehyde, thiourea, and thioacetamide by alkaline Fe(CN)g, whereas no effect is observed in the oxidation of acetaldehyde.85 The orders of reaction have been determined and a mechanism was proposed. 

The lithium enolates of cyclopentanone and cyclohexanone undergo addition-elimination to the 2,2-dimethylpropanoic acid ester of ( )-2-nitro-2-hepten-l-ol to give 2-(l-butyl-2-nitro-2-propenyl)cycloalkanones with modest diastereoselection. An analogous reaction of the enolate ion of cyclohexanone with the 2,2-dimethylpropanoic acid ester of (Z)-2-nitro-3-phenyl-2-propenol to give 2-(2-nitro-l-phenyl-2-propenyl)cyclohexanones was also reported. The relative configuration of these products was not however determined6. 

Flavoprotein 1,2-monooxygenases are used for the insertion of an atom of oxygen into the ring that is the first step in the degradation of both cyclopentanone and cyclohexanone before hydrolysis of the resulting lactones and dehydrogenation (Figure 3.5). There are two types of cycloalkanone... 

The chemical shift dependence of the carbonyl resonances on ring size in cycloalkanones is particularly remarkable In the series of cycloalkanones, cyclopentanone is found to have the largest carbonyl shift (219.6 ppm). The CO signals of cyclobutanone and cyclohexanone are both observed at higher field (x 209 ppm). The carbonyl carbons of cy-clooctanone and cyclononanone are much more deshielded than those of cyclohexanone, cycloheptanone, cyclodecanone and cycloundecanone. The carbonyl resonances of the twelve to seventeen membered ring ketones occur at S values similar to those of acyclic ones [282, 288]. 

Cyclocarbonylation (9, 205-206). McMurry and Andrus have examined the scope of the reaction of Collman s reagent with unsaturated tosylates as a route to cycloalkanones and have concluded that the reaction is useful for preparation only of cyclopentanones and cyclohexanones from olefinic tosylates in which the double bond is monosubstituted. Yields are higher with primary tosylates than with secondary tosylates. 

Oxidative cleavage of cycloalkanones The formation of acyclic keto acids from a-substituted cyclopentanones and cyclohexanones by Cu(NOj)2 -mediated autooxidation in aqueous acetic acid is quite efficient (60-96% yield). 

Simple mixtures can be determined from their IR spectra. For example mixtures of cycloalkanones show characteristic differences of the carbonyl group cyclobutanone (1788 cm ), cyclopentanone (1746 cm ), and cyclohexanone (1718 cm ). IR spectroscopy has been applied to deuteration of organic samples. It is found that the C—H stretch bands disappear from the 3000 cm and the C—D stretch bands appear in the 2200 cm region. It is possible by calibrating pure compounds to determine the isotopic purity in routine analysis. 

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