Dicyclohexylcarbodiimide → tert.-butyl(1R,cis)2,2-dimethyl-3-[Z-2-(cyclobutoxycarbonyl)-ethenyl]cyclopropane-carboxylate

Participants

Reaction Steps

1.7 ml of cyclobutanol were added to a solution of 4 g of tert.-butyl (1R, cis) 2,2-dimethyl-3-[Z-2-carboxy-ethenyl]-cyclopropane-carboxylate in 20 ml of methylene chloride and 3.45 g of dicyclohexylcarbodiimide and a solution of 28 mg of 4-dimethylamino-pyridine in 20 ml of methylene chloride were added thereto at 0° to 5° C. with stirring. The mixture was stirred for 2 hours at 5° C. and 2 hours at room temperature and was then filtered. The filtrate was evaporated to dryness under reduced pressure and the residue was chromatographed over silica gel. Elution with a 9-1 n-hexane-isopropyl ether mixture yielded 2.3 g of tert.-butyl (1R,cis) 2,2-dimethyl-3-[Z-2-(cyclobutoxycarbonyl)-ethenyl]-cyclopropane-carboxylate.

Provenance & Evidence