反应详情

温度

20 °C

4 g of the product of Step A, 3.4 g of dicyclohexylcarbodiiumide and 6 mg of 4-dimethylamino-pyridine were added to 30 ml of methylene chloride followed by the addition of 1.5 ml of ethanol and the mixture was stirred at 20° C. for 16 hours. The mixture was filtered and the filtrate was evaporated to dryness under reduced pressure. The residue was chromatographed over silica gel and was eluted with a 9-1 cyclohexane-ethyl acetate mixture to obtain 4.25 g of tert.butyl (1R, cis) 2,2-dimethyl-3-(ethoxycarbonyl-ethynyl)-cyclopropane-carboxylate.

1. filtrationThe mixture was filtered
2. customthe filtrate was evaporated to dryness under reduced pressure
3. customThe residue was chromatographed over silica gel
4. washwas eluted with a 9-1 cyclohexane-ethyl acetate mixture