The addition of lithium salts of 0-alkyloximes to aldehydes: Synthesis of ß-keto ö-alkyloximes

Addition of lithium salts of oxime O-ethers to aldehydes affords the thermodynamically unfavored ^-hydroxy (Z)-O-alkyloximes. Oxidation of the hydroxy function with chromium trioxide/pyridine complex gives the ß-keto O-alkyloximes. Facile alkylation of the 1,3-dicarbonyl analogs is possible via their sodium or lithium salts.