tert.-butyl(1R,cis)2,2-dimethyl-3-[(Z)-2-(methoxy carbonyl)-ethenyl]-cyclopropane carboxylate → (1R, cis)2,2-dimethyl-3-[(Z)-2-(methoxy carbonyl)-ethenyl]-cyclopropane-carboxylic acid

Participants

Reaction Steps

A solution containing 13.5 g of the product of Step B, 100 cm3 of toluene and 400 mg of hydrated p-toluene sulfonic acid was refluxed for 3 hours and then was evaporated to dryness under reduced pressure. The 11.2 g of residue were chromatographed over silica gel and was eluted with a 60-39-1 cyclohexane-ethyl acetate-acetic acid mixture. The eluate was evaporated to dryness under reduced pressure to obtain 9.6 g of (1R, cis)2,2-dimethyl-3-[(Z)-2-(methoxy carbonyl)-ethenyl]-cyclopropane-carboxylic acid melting at 110° C. and having a specific rotation of [α]D20 =+75.5°±2° (c=1% in CHCl3).

Provenance & Evidence