(1R,cis) 2,2-dimethyl-3-(cyclopentylidenemethyl)-cyclopropane-carboxylic acid → ethyl (1R,cis) 2,2-dimethyl-3-cyclopentylidenemethyl-cyclopropane-1-carboxylate

Participants

Reaction Steps

7.5 g of ethyl N,N'-diisopropyl-carbamimidate were added to a solution of 7.8 g of (1R,cis) 2,2-dimethyl-3-cyclopentylidenemethyl-cyclopropane-1-carboxylic acid in 20 ml of ethyl acetate and the mixture was refluxed for 2 hours and was filtered. The filtrate was evaporated to dryness and the 13 g of residue were chromatographed over silica gel. Elution with a 7-3 cyclohexane-ethyl acetate mixture and the fraction with a Rf=0.45 was evaporated to dryness under reduced pressure to obtain 1.4 g of ethyl (1R,cis) 2,2-dimethyl-3-cyclopentylidenemethyl-cyclopropane-1-carboxylate with a specific rotation of [α]D20 =+76°±2° (c=1% in ethanol).

Provenance & Evidence