Cycloalkanones, oxidative cleavage

Oxidative Cleavage of Ketones. Aldehydes, and Alcohols Cycloalkanone oxidative ring opening... 

Rothenberg, G., Sasson, Y. Extending the haloform reaction to non-methyl ketones oxidative cleavage of cycloalkanones to dicarboxylic acids using sodium hypochlorite under phase transfer catalysis conditions. Tetrahedron 1996, 52,13641-13648. 

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). 

An oxidative cleavage of cycloalkanones to unsaturated aldehyde-esters has been developed. Thus, for example, cyclononanone was converted into 2,2-dithio-trimethylenecyclononanone, which was cleaved using lead(iv) acetate (66 %), and the product so obtained treated with methanol and sodium periodate to give (208 in = 5). Cyclododecanone was similarly converted into (208 n = 8). 1,2-Bis(trimethyl-silyloxy)cycloalkenes, prepared by acyloin condensations, have been converted into 2-alkyl-2-hydroxycycloalkanones by treatment with methyl-lithium and an alkyl halide, and the oximes of these a-hydroxyketones cleaved to give open-chain co-cyanoketones using mesyl chloride-pyridine. ... 

Photolysis of 2-(2 -cyclopropylcyclopropyl)cycloalkanones (108 n = 1, 2) gave ring-expanded products e.g. (108 n = 1) gave a mixture of cyclododecanone (61 %) and 2-cyclopropylcyclononanone (20%). Ring expansion of cyclic mono- and diacetylenes by 4, 8 or 12 carbon atoms can be achieved by nickel-catalysed cyclooligomerization with buta-1,3-diene, followed by oxidative cleavage thus cyclo-tetradec-l,8-diyne was converted into cyclotriacontane. ... 

Scheme 15.49 Copper-catalysed oxidative cleavage of cycloalkanone with dio q gen.

Reduction, carboxyl groups, 56,83 Reduction of a,0-unsaturated p-toluene-sulfonyl-hydrazones to alkenes, 59,42 Reductive alkylation, 56,52 Reductive cleavage, 56, 101 Resolution of amines, 55,80, 83 Rexyn 201,55,4 Rhodium(III) oxide, 57, 1 Ring contraction, 56, 107 Ring expansion of cycloalkanones to cycloalkenones, 59, 113... 

Ballini, R., Curini, M., Epifano, F., Marcotullio, M. C., Rosati, O. A new, modulated, oxidative ring-cleavage of a-nitro cycloalkanones by Oxone. Synthesis of a,co-dicarboxylic acids and a,to-dicarboxylic monomethyl esters. Syn/eff 1998, 1049-1050. 

Ring cleavage. Several oxidants can cleave lactols at the Ca—C 3 bond, and the PhI(OAc)2-l2 pair is useful for attaching an iodine atom to C(3 in the process. From bicychc lactols such as those prepared from alkylation of cycloalkanones with epoxides as substrates iodolactones are obtained. ... 

Oxidative ring cleavage. Trost and Hiroi have developed a method for cleavage of cycloalkanones that involves essentially two steps selective sulfenyla-tion with diphenyl disulfide (5, 276-277 this volume) and oxidation with lead tetraacetate. The method is illustrated for estrone methyl ether as the substrate. Thus this five-membered ring ketone can be converted in high overall yield into... 

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