Iodocyclization of N-Aryl-3-phenylpropiolamides by I2/CAN: A Convenient Route for the Selective Synthesis of Quinolin-2-ones

A general method has been developed for the selective synthesis of 3-iodoquinolin-2-ones and spiro[4.5]trienes via intramolecular iodocyclization of N-ortho-substituted aryl)-3-phenylpropiolamides using iodine/cerium(IV) ammonium nitrate reagent under mild reaction conditions. The electronic effect of ortho-substituents electron-rich and electron-deficient group) triggers the two different reaction pathways resulting to iodocyclized quinolin-2-one and ipso-iodocyclized spiro-type compounds.