A new method was developed for the synthesis of quinoxalines. This method employs N-arylenamines and TMSN3 as the starting materials and implements two oxidative C-N bond-forming processes in a tandem pattern by using (diacetoxyiodo)benzene as the common oxidant. The present reaction conditions are mild and simple and thus are useful in practical synthesis.

This paperr eveals that visible light irradiation with Ru(phen) 3 Cl 2 as photocatalyst can induce ethyl 2-(N-arylcarbamoyl)-2-chloroiminoacetates to undergo N À Cl cleavage to give a-(aminocarbonyl)iminyl radicalsu nder an argon atmosphere.T he subsequent cyclization of the thus formed iminyl radicals affords quinoxalin-2(1H)-one productsi ng ood yield in the presence of an inorganic base such as Na 2 CO 3 .T he reactions proceeded very well even without using ap hotocatalyst when DMF was used as the solvent. Thesep rotocols provide an ew,s imple method for the generation of iminyl radicals,a nd the reactions described herein constitute an efficient method for the synthesis of quinoxalin-2(1H)-onederivatives.

N-Alkyl enamines can be transformed into 2,4,5-trisubsituted imidazoles by reacting with (diacetoxyiodo)benzene and TMSN under the catalysis of a copper salt such as Cu(OAc). Tetrabutyl ammonium iodide was also capable of promoting the reaction. The transformation from N-alkyl enamines into 2,4,5-trisubsituted imidazoles took place in a domino azidation/intramolecular C(sp)-H amination pattern. The present reaction provides a new efficient method for the preparation of 4-(trifluoromethyl) imidazoles.

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