反应详情

35 ml of a 1.6 molar solution of n-butyllithium in hexane (61 mmol) are added dropwise to a solution of 8.1 ml of diisopropylamine (85 mmol) in 20 ml of tetrahydrofuran at −78° C. Then a solution of 10.0 g (50 mmol) of methyl 2-(4-chloro-phenyl)-propionate in 30 ml of tetrahydrofuran is added dropwise at −78° C. Gaseous formaldehyde is piped into the reaction mixture at −20° C. for 30 minutes. After the addition of 5% citric acid and glacial acetic acid the mixture is extracted with ethyl acetate. The organic phases are washed with 1N sulphuric acid, water, saturated sodium bicarbonate solution and saline solution and dried over magnesium sulphate. The crude product is purified on silica gel, eluting with cyclohexane/ethyl acetate (19:1; 9:1; 4:1; 1:1 and 0:1). The uniform fractions are combined and concentrated by evaporation.

1. extractionis extracted with ethyl acetate
2. washThe organic phases are washed with 1N sulphuric acid, water, saturated sodium bicarbonate solution and saline solution
3. dry with materialdried over magnesium sulphate
4. customThe crude product is purified on silica gel
5. washeluting with cyclohexane/ethyl acetate (19:1; 9:1; 4:1; 1:1 and 0:1)
6. concentrationconcentrated by evaporation