Efficient asymmetric synthesis of cis-2-methylcyclopropanecarboxylic acid

Article abstract of DOI:10.1016/0040-4020(96)00792-2

We have developed a versatile method for the synthesis of enantiomerically pure cis-2-methylcyclopropanecarboxylic acid (-)-2, a component of curacin A, and its enantiomer, (+)-2. Double-asymmetric Simmons-Smith cyclopropanation of the dienes 5 and 9 derived from diethyl L-tartrate proceeded with excellent diastereofacial selectivity (>99% de) to give the dicyclopropanes 6 and 10, which were converted to both enantiomers of 2.