Trichloroethanol → tert.butyl(1R,cis)2,2-dimethyl-3-(2,2,2-trichloroethoxycarbonylethynyl)-cyclopropane-carboxylate

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Reaction Steps

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.

Provenance & Evidence