C(sp)-H functionalization of aldehyde-derived hydrazones via a radical process.

This review is focused on the recent advances in the C(sp)-H functionalization of aldehyde-derived hydrazones via a radical process. Diverse substituted hydrazones including N-heterocycles are afforded under mild conditions with excellent selectivities. In general, an aminyl radical as the key intermediate is involved during the reaction process, and a broad reaction scope with good functional group tolerance can be observed. In some cases, a photocatalyst under visible light irradiation is involved, which initiates the radical reaction.