Triethylamine → (3aR,7aR)-7,7-diphenyl-2-[(S)-2-phenylpropionyl]-4-perhydroisoindolone

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Reaction Steps

N,N'-Carbonyldiimidazole (0.66 g) is added to a solution of (S)-2-phenylpropionic acid (0.62 g) in dry dichloromethane (30 cc), cooled to +5° C. The mixture is stirred for 40 minutes at +5° C. and a solution of (3aR,7aR)-7,7-diphenyl-4-perhydroisoindolone hydrochloride (1.35 g) and triethylamine (0.57 cc) in dichloromethane (40 cc) is then added. The reaction mixture is stirred at 20° C. for 16 hours, then washed with distilled water (2×50 cc), dried over magnesium sulphate and filtered and the filtrate is concentrated to dryness under reduced pressure (2.7 kPa). The residue is chromatographed on a silica gel column (0.2-0.063 mm, diameter 1.8 cm, height 15 cm), eluting with ethyl acetate and collecting 15 cc fractions. The first fraction is concentrated to dryness under reduced pressure (2.7 kPa). (3aR,7aR)-7,7-diphenyl-2-[(S)-2-phenylpropionyl]-4-perhydroisoindolone (1 g) is obtained in the form of a white meringue. [α]D20 =-231° (c=1, methanol).

Provenance & Evidence