Deprotection of Benzyl-Derived Groups via Uranyl-Photocatalysis

To circumvent the hazards associated with flammable/explosive hydrogen and address substrate compatibility issues in reductive systems, we developed a mild method for benzyl deprotection facilitated by uranium under visible light irradiation at ambient conditions. The uranium-oxo species, as a metal-oxo-type photosensitizer, demonstrates compatibility with moisture, enabling benzyl C-H activation through ligand-to-metal charge transfer (LMCT) excitation. Subsequent capture of the benzyl radical by atmospheric oxygen induces oxidation at the benzylic position. Removal of the semiacetal occurs, resulting in C-O bond cleavage under acidic conditions. This methodology, featuring mild conditions and operational convenience, is compatible with moisture and oxygen. It presents a complementary strategy for benzyl deprotection for the synthesis of pharmaceuticals and organic materials.