Heteroatom-Functionalization of Aromatic Rings Using Near Infrared Light-Activatable Catalysts

The development of molecular transformation reactions driven by highly penetrating near-infrared (NIR) light presents a promising platform for organic synthesis. Here, we report a reaction that allows the heteroatom-functionalization of aromatic rings using a phthalocyanine-based NIR photocatalyst. The use of phthalocyanine zinc complexes capable of generating singlet oxygen ( 1 O 2 ) upon NIR irradiation was investigated, focusing on the generation of aryl radicals by the reaction of arylhydrazine derivatives with 1 O 2 . Arylhydrazine hydrochloride, a precursor that is stable and easy to handle, enabled the incorporation of various heteroatoms, including P, S, and B, onto the aromatic ring through electrophilic/nucleophilic trapping with aryl radicals. This methodology enables the selective transformation of fluorescent dyes and facilitates reactions even under shielded conditions, which are often challenging with conventional photochemical reactions. Thus, our strategy offers a novel approach to the functionalization of aromatic rings using NIR light.