N-H Insertion of Anilines on N -Tosylhydrazones Induced by Visible Light Irradiation.

Diazo compounds and their precursors represent an interesting chemical category for organic synthesis. Particularly, N -tosylhydrazones have attracted attention for their easy accessibility and diverse reactivity, including carbene transfer reactions. We described a visible light-induced N-H insertion reaction of anilines on in situ -generated diazo compounds. Optimal conditions using DBU in toluene efficiently yielded the desired products. Mechanistic studies enabled us to trap a carbene intermediate that plays a key role in the transformation.