反应详情

To a solution of 2-(S)-(3,4-dichlorophenyl)-pent-4-enoic acid (5.04 g, 20.6 mmol) in 60 mL of dichloromethane was added 2.15 mL (24.6 mmol) of oxalyl chloride and 0.1 mL of dimethylformamide with cooling in an ice-water bath. The cooling bath was then removed and the reaction mixture was stirred at rt overnight. The solvent was removed under reduced pressure, and the resulting material was diluted in ethyl acetate and concentrated in vacuo in order to remove residual HCl. The residual crude acid chloride was dissolved in 70 mL of ether and was slowly added to a 100 mL ether solution of diazomethane (77 mmol). After stirring for 2 hr at rt, the solvent was removed under vacuum. The resulting yellow oil was chromatographed on silica gel column eluting with a gradient of hexane:ethyl acetate=20:1 to 3:1 to give 4.66 g (84%) of diazomethyl-(2-(S)-(3,4-dichlorophenyl)-pent-4-enyl)-ketone.

1. temperaturewith cooling in an ice-water bath
2. customThe cooling bath was then removed
3. customThe solvent was removed under reduced pressure
4. additionthe resulting material was diluted in ethyl acetate
5. concentrationconcentrated in vacuo in order
6. customto remove residual HCl
7. dissolutionThe residual crude acid chloride was dissolved in 70 mL of ether
8. stirringAfter stirring for 2 hr at rt
9. customthe solvent was removed under vacuum
10. customThe resulting yellow oil was chromatographed on silica gel column
11. washeluting with a gradient of hexane