Process for the preparation of a cyclopropanecarboxylic acid ester

摘要

The compounds of formula IIA below in the form of an optical isomer having the (R) configuration at C1 of the ring of the cyclopropane are obtained from a derivative of the cyclopropane containing the acyl residue of formula IIB below. R<2> and R<3> represent F, Cl or Br and R represents 3-phenoxybenzyl, alpha -cyano-3-phenoxybenzyl or 5-benzyl-3-furylmethyl. The process consists in introducing the residue R by esterification and in introducing the dihalovinyl residue in position 3 by the Wittig reaction using triphenylphosphine and a carbon tetrahalide. The compounds of formula IIA are particularly effective insecticides. <IMAGE>