An Efficient One-Pot Synthesis of Oxime Ethers from Alcohols Using Triphenylphosphine/Carbon Tetrachloride

A convenient and efficient one-pot O-alkylation of oximes from alcohols using triphenylphosphine in carbon tetrachloride is described. In this method, treatment of alcohols with a mixture of triphenylphosphine, carbon tetrachloride, oxime, and DBU in the presence of catalytic amounts of tetrabutylammonium iodide in refluxing acetonitrile regioselectively furnishes the corresponding O-alkyl ethers in good yields. This methodology is highly efficient O-alkylation of oximes with various structurally diverse alcohols. Semiempirical quantum-mechanic calculations (AM1) for unsymmetrical oxime ethers, indicated a lower heat of formation for Z-isomers.