PROCESS FOR THE STEREOSELECTIVE SYNTHESIS OF THE E ISOMER OF ARYL ALKYL OXIMES

摘要

Mixtures of the E and Z isomers of aryl alkyl oximes are converted to 98% or greater E isomer by a process comprising treating a solution of a mixture of E and Z isomers in an organic solvent with a protic or Lewis acid, under anhydrous conditions, to precipitate 98% pure E isomer of an immonium complex and neutralizing the precipitate with an excess of dilute organic/inorganic base, such as Na2CO3 or NaHCO3. The E isomer of the ketoxime is precursor for highly insecticidal ketoximinoethers.