| abstract |
Embedded image a) converting a compound of formula (VII) wherein X, Y, Y 1 and Z are as defined for compounds (VIIa) and (VIIb) in a substantially optically pure chiral amine and solvent To form diastereoisomeric salts; b) separating the diastereoisomeric salts of each enantiomer; c) diastereomeric formation of each enantiomer by hydrolysis of an acid or base. X is a leaving group; comprising converting the stereoisomer salts separately to compounds of formulas (VIIa) and (VIIb); Y and Y 1 are independently Cl or Br; And methods for preparing compounds of formulas (VIIa) and (VIIb) wherein Z is Cl, Br or a haloalkyl group, the use of said compounds in the preparation of pyrethroid insecticides, and novel intermediates. |