process for the production of enantiomerenreinen pyrethroid insecticides

摘要

A process for producing compounds of formula (VIIa) and (VIIb) wherein X is a leaving group; Y and Y1 are idependently Cl or Br; and Z is Cl, Br or a haloalkyl group which process comprises a) reacting a compound of formula (VII) wherein X, Y, Y1 and Z are as defined for compounds (VIIa) and (VIIb) with a substantially optically pure chiral amine in a solvent to form a diastereoisomeric sa b) separating the diastereomeric salt of each enantiomer; c) converting the diastereomeric salt of each anantiomer separately to compounds of formulae (VIIa) and (VIIb) respectively by acid or base hydrolysis, the use of the compounds in making pyrethroid insecticides and novel intermediates.