Visible light-promoted tandem azidation/cyclization of N-arylenamines towards quinoxalines.

This paper reports that N -arylenamines can be converted into quinoxalines via tandem azidation/intramolecular C H amination under visible light irradiation by using 1-azidyl-1,2-benziodoxole as the azidating agent. The substituent was found to have a critical influence on the reaction, and thus different conditions were required to fit the substrates of varied structural features. The conversion of N -aryl-3-arylenamine esters into the corresponding quinoxalines proceeded well under metal-free conditions, whereas Cu(OAc) 2 was required when N -aryl-3-trifluoromethyl enamine esters were used as the substrates. This method was also applied to the preparation of 2,3-diarylquinoxalines by using Ru(bpy) 3 Cl 2 as the photoredox catalyst. The reactions revealed herein provide an efficient approach towards quinoxalines. [ABSTRACT FROM AUTHOR]