反应详情

6.2 g of dicyclohexylcarbodiimide were introduced into a solution of 7.15 g of tert.-butyl (1R,cis) 2,2-dimethyl-3-(2-carboxyethynyl)-cyclopropane-carboxylate and 80 mg of 4-dimethylamino-pyridine in 35 ml of methylene chloride and the reaction mixture was stirred for 10 minutes after which 4.5 of 2,2,2-trichloroethanol were added. The mixture was stirred for 1 hour and was filtered. The filtrate was washed with N hydrochloric acid, then with water until neutral, dried and evaporated to dryness. The 14 g of oil residue were chromatographed over silica gel and eluted with a 97-3 mixture of benzene-ethyl acetate to obtain 9 g of tert.butyl (1R,cis) 2,2-dimethyl-3-(2,2,2-trichloroethoxycarbonylethynyl)-cyclopropane-carboxylate melting at 70-71° C.

1. additionwere added
2. filtrationwas filtered
3. washThe filtrate was washed with N hydrochloric acid
4. dry with materialwith water until neutral, dried
5. customevaporated to dryness
6. customThe 14 g of oil residue were chromatographed over silica gel
7. washeluted with a 97-3 mixture of benzene-ethyl acetate