反应详情

A mixture of ethyl 2-chloro-3-oxo-3-phenylpropionate (CI, EXAMPLE 1, 6.8 g, 30 mmol) in dichloromethane (68 ml) is cooled to −5° and a solution of zinc borohydride (0.4 M, 38 ml, 15 mmol) in ether is added dropwise over 30 mins. After the addition, the reaction mixture is stirred at 0° for 30 mins and then poured into a cold solution (0°) of acetic acid (5 ml) in water (15 ml). The resulting mixture is extracted with dichloromethane (30 ml×2). The combined organic extracts are washed with water (30 ml), dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue is chromatographed (silica gel; ethyl acetate/hexane, (5/95 to 25/75) to give the title compound which is a 1:9 mixture of anti and syn isomers as determined by NMR.

1. temperatureis cooled to −5°
2. additionAfter the addition
3. extractionThe resulting mixture is extracted with dichloromethane (30 ml×2)
4. washThe combined organic extracts are washed with water (30 ml)
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe residue is chromatographed (silica gel