Heteroarylation of mono- and dichloroarenes via phenothiazine organophotoredox catalysis

ABSTRACT 2-Arylpyrroles are key structural motifs found in a wide range of pharmaceuticals and functional materials. Although the photocatalytic heteroarylation of pyrroles with aryl iodides and bromides has been extensively developed for the synthesis of 2-arylpyrroles, the corresponding reactions using aryl chlorides remain relatively unexplored owing to the high energy barrier associated with C(sp²)–Cl bond activation. Herein, we report a phenothiazine-based organophotoredox-catalyzed heteroarylation of aryl chlorides with pyrroles for the synthesis of diverse 2-arylpyrroles. Notably, dichloroarenes also efficiently undergo heteroarylation to afford the corresponding bis-heteroarylated pyrroles. Therefore, the present reaction represents a versatile approach to heteroarylation and provides a valuable tool for the synthesis of pharmaceuticals and functional materials.