Visible-light induced phosphonation of quinoxalines and quinoxalin-2(1H)-ones under aerobic metal-free conditions

Phosphonation of quinoxalines and quinoxalin-2(1H)-ones utilizing aerobic oxygen as green oxidant under visible light conditions at room temperature has been described. Both quinoxalines and quinoxalin-2(1H)-ones are compatible with alkyl or aryl phosphonates and provided good yields of products through regioselective C-P bond formation under base/ligand-free conditions. Competitive experiments showed quinoxalin-2(1H)-ones are more reactive than quinoxalines under the present conditions, and the control experiments revealed the present transformation proceeds through a radical mechanism.