反应详情

温度

4 °C

In a 200 ml three necked flask fitted with a magnetic stirrer, under inert atmosphere, cerium ammonium nitrate (11.2 g, 0.02 mol, 3 eq) is added to a solution of 4-(2,2-difluoro-vinyl)-1-(4-methoxy-benzyl)-pyrrolidin-2-one a4 (1.8 g, 6.8 mmol in MeCN/H2O (respectively 70 ml/110 ml) cooled at 4° C. After 5 h at 10° C., the reaction mixture is diluted with water, extracted with AcOEt, dried on MgSO4 and concentrated in vacuo. The residue is diluted with toluene, the solid is filtrated and the solvent is evaporated. The residue is purified by chromatography on silicagel (CH2Cl2/MeOH: 99/01 (v/v)) to afford fraction A1 (0.5 g of the expected compound) and fraction B (0.7 g of a mixture of synthetic intermediates and starting materials). Fraction B is again reacted with cerium ammonium nitrate as above (CAN: 0.78 g, MeCN (30 ml), H2O (50 ml)) to afford after purification, another fraction A2 (0.3 g). Fractions A1+A2 put together give 0.8 g of 4-(2,2-difluoro-vinyl)-pyrrolidin-2-one as (81%) contaminated by traces of 4-methoxybenzoic acid.

1. extractionextracted with AcOEt
2. customdried on MgSO4
3. concentrationconcentrated in vacuo
4. additionThe residue is diluted with toluene
5. filtrationthe solid is filtrated
6. customthe solvent is evaporated
7. customThe residue is purified by chromatography on silicagel (CH2Cl2/MeOH: 99/01 (v/v))