Deoxygenation of a-Aryl-N-Phenylnitrones with Diiodotriphenylphosphorane

Abstract

An efficient and simple method for conversion of a-aryl-N-phenylnitrones [1] into N-benzylideneanilines [3] with diiodotriphenylphosphorane [2], which is formed from triphenylphosphine and iodine, has been investigated. The reaction was completed in a s hort time at room temperature in benzene to give [3] j in high yields (92-96%). The reaction rate was affected by an amount of iodine, and th e reaction was completed immediately by the use of excess of iodine to the phosphine, while the reaction was not completed with a catalytic amount of iodine under the same conditions for 24 h. On the other hand, [1] was deoxygenated except for nitro and dimethylamino derivatives with the phosphine and a catalytic amount of iodine in dichloromethane to give [3]in high yields (94-97%).