| abstract |
A process for the conversion of (+)-R-alpha-cyano-3-phenoxybenzyl (+)-S-alpha-isopropyl-4-chlorophenylacetate (isomer 1) into (-)-S-alpha-cyano-3-phenoxybenzyl (+)-S-alpha-isopropyl-4-chlorophenylacetate (isomer 2), by treating a solution in a suitable solvent of isomer 1, alone or in admixture with isomer 2 with a base, and by removing a proportion of isomer 2 before, during or after the treatment with base. |