反应详情

温度

40 °C

To a solution of cis/trans-4-hydroxycyclohexane carboxylic acid ethyl ester (2:1) (1.0 g, 5.8 mmol) and di-tort-butyl dicarbonate (2.9 g, 13.4 mmol) in dichloromethane (6 ml) was added anhydrous magnesium perchlorate (0.13 g, 0.58 mmol) which was previously activated in high vacuo (ca. 1 mbar) at 150° C. for 1 h. Stirring for 16 h at 40° C. was followed by partitioning between dichloromethane (50 ml) and water (30 ml). The layers were separated. The aqueous layer was extracted with one 50-ml portion of dichloromethane. The combined organic layers were dried over anhydrous sodium sulfate and concentrated in vacuo. Purification by flash-chromatography with n-heptane/tert-butyl methyl ether as eluent gave pure trans-4-tert-butoxy-cyclohexanecarboxylic acid ethyl ester and cis-4-tert-butoxy-cyclohexanecarboxylic acid ethyl ester.

1. customby partitioning between dichloromethane (50 ml) and water (30 ml)
2. customThe layers were separated
3. extractionThe aqueous layer was extracted with one 50-ml portion of dichloromethane
4. dry with materialThe combined organic layers were dried over anhydrous sodium sulfate
5. concentrationconcentrated in vacuo
6. customPurification by flash-chromatography with n-heptane/tert-butyl methyl ether as eluent