反应详情

A mixture of 6.2 g of dicyclohexylcarbodiimide, 7.15 g of tert.-butyl (1R,cis) 2,2-dimethyl-3-(2-carboxy-ethynyl)-cyclopropane-carboxylate, 80 mg of dimethylaminopyridine and 35 ml of methylene chloride was stirred for 10 minutes and 4.5 g of 2,2,2-trichloroethanol were added thereto. The mixture was stirred for one hour and was filtered and the filtrate was washed with N hydrochloric acid and then with water until the wash water was neutral, dried and evaporated to dryness. The 14 g of oil residue were chromatographed over silica gel and eluted with a 97-3 benzene-ethyl acetate mixture to obtain 9 g of tert.-butyl (1R,cis) 2,2-dimethyl-3-[2,2,2-trichloroethoxycarbonyl-ethynyl]-cyclopropane-carboxylate melting at 70°-71° C.

1. stirringThe mixture was stirred for one hour
2. filtrationwas filtered
3. washthe filtrate was washed with N hydrochloric acid
4. customdried
5. customevaporated to dryness
6. customThe 14 g of oil residue were chromatographed over silica gel
7. washeluted with a 97-3 benzene-ethyl acetate mixture