Potassium Carbonate → (3aRS,7aRS)-2-benzyl-7,7-dimethyl-2,3,3a, 4,7,7a-hexahydro-1H-4-isoindolone

Participants

Reaction Steps

To a solution of 15.96 g of 4,4-dimethyl-2,5-cyclohexadienone and 46 cm3 of N-butoxymethyl-N-trimethylsilylmethylbenzylamine in 200 cm3 of dichloromethane are added, at a temperature of 10° C., 8 drops of trifluoroacetic acid. The reaction mixture is brought to reflux for 2 hours and potassium carbonate is then added and the solution is filtered through a sinter funnel and concentrated to dryness under reduced pressure (2.7 kPa). The residue is chromatographed on a column of silica gel (particle size 0.04-0.06 mm, diameter 8.5 cm, height 30 cm), eluting under a pressure of 0.5 bar of nitrogen with a mixture of cyclohexane and ethyl acetate (80/20 by volume) and collecting 100 cm3 fractions. Fractions 38 to 56 are combined and concentrated to dryness under reduced pressure (2.7 kPa). 14.7 g of (3aRS,7aRS)-2-benzyl-7,7-dimethyl-2,3,3a, 4,7,7a-hexahydro-1H-4-isoindolone are obtained in the form of a yellow oil.

Provenance & Evidence