Metal-free C-H functionalization of 2H-imidazole 1-oxides with pyrrolyl fragments in the design of novel azaheterocyclic ensembles.

The methodology of direct C(sp2)-H functionalization has for the first time been applied as an efficient and advanced approach to carry out C-H/C-H coupling of 2H-imidazole 1-oxides and pyrroles. The atom-economical method used does not require either any auxiliary group in the starting substrates, or catalysis by transition metals. As a result, a number of novel 1H-pyrrol-2-yl-2H-imidazoles, that are particularly of interest in the design of bioactive molecules, have been prepared under mild conditions and in good to excellent yields.