Abstract <p>The oxidation of <i>N</i>-tosyl-, <i>N</i>-benzoyl-, and <i>N</i>-pivaloyl-2-(cycloalk-1-en-1-yl)anilines with ozone followed by the reduction of the ozonation products with dimethyl sulfide in methylene chloride or hydroxylamine hydrochloride in isopropanol or methаnol was studied. The oxidation of <i>N</i>-tosylates in CH₂Cl₂ followed by treatment with Me₂S results in the exclusive formation of ketoaldehydes, whereas the reduction of the ozonation products in alcohols under the action of hydroxylamine hydrochloride yields acids and their esters in various ratios. The reduction of the ozonation products of 2-(2-cyclohex-1-en-1-yl-6-methylphenyl)-1<i>H</i>-isoindole-1,3(2<i>H</i>)-dione in MeOH under the action of hydroxylamine hydrochloride gives methyl 6-[2-(1,3-dioxo-1,3-dihydro-2<i>H</i>-isoindol-2-yl)-3-methylphenyl]-6-oxohexanoate as a single isolated product. The oxidation of <i>N</i>-[2-(6-methoxycyclohex-1-en-1-yl)-6-methylphenyl]-4-methylbenzenesulfonamide with ozone followed by treatment of the reaction mixture with hydroxylamine hydrochloride leads to methyl 5-methoxy-6-(3-methyl-2-{[(4-methylphenyl)sulfonyl]amino}phenyl)-6-oxohexanoate and <i>N</i>-{2-[6-(hydroxyimino)-2-methoxyhexanoyl]-6-methylphenyl}-4-methylbenzenesulfonamide in a 10 : 7 ratio. The oxime is formed as 1 : 2 <i>syn</i>/<i>anti</i> mixture, treatment, upon treatment with 2 equiv of methanesulfonyl chloride in triethylamine, is converted into the axial <i>syn/anti</i> atropisomers of <i>N</i>-[2-(5-cyano-2-methoxypentanoyl)-6-methylphenyl]-4-methyl-<i>N</i>-(methylsulfonyl)benzenesulfonamide in a 8 : 1 ratio, but their assignment to specific isomers remains unclear.</p>