Visible-light-accelerated amination of quinoxalin-2-ones and benzo[1,4]oxazin-2-ones with dialkyl azodicarboxylates under metal and photocatalyst-free conditions

A direct sp3 C-H amination of cyclic amines (dihydroquinoxalinones and dihydrobenzoxazinones) with dialkyl azo dicarboxylates accelerated by visible-light irradiation under metal and photocatalyst-free conditions is described. This protocol features very mild reaction conditions for the synthesis of aminal quinoxaline and benzoxazine derivatives with good to high yields (up to 99%). These aminal derivatives respresent versatile building blocks for the divergent synthesis of quinoxalin-2-one derivatives.