Palladium-catalyzed regioselective C1-selective nitration of carbazoles

Carbazoles are ubiquitous and privileged heterocyclic scaffolds in various functional organic materials and naturally occurring products. Although extensive efforts have focused on developing synthetic strategies toward carbazole derivatives, direct regioselective functionalization of the carbazole core remains challenging due to the inherently higher reactivity at the C3/C6 positions. In this study, we report a palladium-catalyzed, directing group-assisted, regioselective C1-H nitration of carbazoles. The protocol features a removable directing group and is amenable to gram-scale synthesis. This strategy provides a valuable platform for the selective functionalization of carbazoles, offering potential applications in optoelectronics, functional organic materials, and related areas while contributing to the advancement of C-H activation methodologies.