Halogen Radical-Enabled\nDearomatization of <i>N</i>‑Arylpropiolamides via\nPhotoinduced Sequential Halogenation/Spirocyclization/Oxidation\nProcess

Here we report a strategy that eliminates the need for\nphotocatalysts\nand external additives, which provides an operable and mild method\nfor halogen radical-enabled dearomatization of <i>N</i>-arylpropiolamides\nunder an oxygen atmosphere at room temperature. The method is applicable\nto a wide range of substrates, extending beyond the limited scope\nof <i>p</i>-methoxyl <i>N</i>-phenylpropynamides.\nFurthermore, several functional synthetic intermediates and anticancer\nbioactive molecules were successfully derived from 3-halogenated\nazaspiro[4.5]trienones.