NH4I-catalyzed chalcogen(S/Se)-functionalization of 5-membered N-heteroaryls under metal-free conditions

Abstract Herein, we described the NH 4 I-catalyzed C H bond chalcogenation of N -heteroaryls in the presence of a minimum amount of DMSO/H 2 O/acetic acid as additives ( 2.5/2.5/1 M equiv., respectively), under metal-free conditions. Under optimized conditions, a wide variety of sulfenyl/selenyl imidazo[1,2- α ]pyridines were prepared in very good yields. Moreover, the present approach was also highly efficient for the chalcogenation of different 5-membered N -heteroaryls, e.g., indole, imidazothiazole, indazole and imidazopyrimidine derivatives.