trans-(1R,2R)-1-benzyl-2-phenylcyclopropanecarboxylic acid.

The cyclopropane ring of the title compound, C17H16O2, shows a high level of substituent-induced bond-length asymmetry. The carboxyl group adopts a conformation that prompts electron-density transfer from the ring towards the carbonyl pi system.

A general stereoselective method for the synthesis of cyclopropanecarboxylates. A new version of the homologous Horner-Wadsworth-Emmons reaction.

The synthesis of alpha-, beta- and gamma-substituted alpha-phosphono-gamma-lactones was accomplished using different ring closure and ring homologation strategies. It was found that the lactones could be selectively transformed into the corresponding ethyl cyclopropanecarboxylates by treatment with sodium ethoxide in boiling THF. The reported reaction provides an attractive alternative to the classical homologous Horner-Wadsworth-Emmons approach to the construction of cyclopropanes with electron-withdrawing functionalities.