Expanding Perchlorate Use for C–H Oxidative Transformations: A Tandem Photo- and Iron-Catalytic Strategy

We report an iron-catalyzed, light-driven method to enable the use of perchlorates (ClO₄ ^-) to promote C-H oxygenation reactions. In comparison to thermal reactions, introduction of an anthraquinone (AQ) photocatalyst provided distinct reaction outcomes that are proposed to be facilitated by distinct <i>H</i>-atom transfer (HAT) reactivity. Acyclic substrates such as di- and triphenylmethane were oxygenated to form ketones or alcohols, while benzylic substrates containing <i>S</i>- or <i>N</i>-heteroatoms underwent C(sp³)-X (X = S, N) oxidative cleavage to form aldehydes. Appended hydrogen bonds (H-bonds) within the ligand's secondary sphere serve a primary role to facilitate both reactions.