A Simple Process for the Synthesis of Methyl (±)-Cis-3,-Formyl-2-2-Dimethyl-1-1-Cyclopropanecarboxylate

Abstract

Cis-3-formyl-2,2,dimethyl-1-cyclopropanecarboxylic acid (1, R = H, existing as its bicyclic hydroxy lactone) and its esters are the most valuable intermediates for the synthesis of pyrethroids¹, since the introduction of a substituted vinyl group at the aldehyde function can lead to any desired pyrethroid, with the cis geometry at the cyclopropane ring. Pyrethoroids where the cis stereochemistry is necessary for maximum insecticidal activity include most of the commercially important photostable products like deltamethrin², cyhalothrin³ (possessing acaricidal activity), and tefluthrin, a recently introduced soil active pyrethroid.