Reactivity of <i>p</i>‑Toluene­sulfonyl­methyl Isocyanide: Iron-Involved C–H Tosylmethylation of Imidazopyridines in Nontoxic Media

A novel iron-involved tosylmethylation of imidazo­[1,2-α]­pyridines with p-toluenesulfonyl­methyl isocyanide in a solvent mixture of H2O and PEG400 under an Ar atmosphere has been developed. This protocol provides a facile synthetic route for the functionalization of the imidazo­[1,2-α]­pyridine scaffold with broad substrate compatibility, which is less expensive and environmentally friendly. The current methodology could further enable regioselective C–H tosylmethylation of indole at the C3 position. Also, p-toluene­sulfonyl­methyl isocyanide was utilized as the tosylmethylating reagent for the first time.