Toluene → 4,4a,5,6,7,8-Hexahydro-2(3H)-naphthalenone

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Reaction Steps

Toluene (300 ml) and methyl vinyl ketone (42 ml) were added to 1-(4-(1,4-dioxaspiro[4.5]decan-8-yl)cyclohex-1-enyl)pyrrolidine (105.8 g) obtained in the first step in a reaction vessel at room temperature under an atmosphere of nitrogen, and the mixture was refluxed for 6 hours. After the reaction mixture had been cooled to room temperature, sodium acetate (18 g), acetic acid (36 ml) and water (60 ml) were added, and the mixture was refluxed for 4 hours. After the reaction mixture had been cooled to room temperature, water (200 ml) was added, and then the aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, and dried over anhydrous magnesium sulfate. The methanol was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (eluent: ethyl acetate/n-heptane=1/5 by volume) and then by recrystallization (solvent: Solmix/n-heptane=1/9 by volume) to give 6-(1,4-dioxaspiro[4.5]decan-8-yl))-4,4a,5,6,7,8-hexahydronaphthalene-2(3H)-one (43.3 g).

Provenance & Evidence