Iridium-Catalyzed ortho-Directed C-H Borylation of Nitroarenes.

ortho-Boryl nitroarenes have vast applications as building blocks in organic synthesis. Traditional methods of synthesizing these compounds require an ortho-halo nitroarene starting material and often stringent conditions. Directed ortho-borylation of nitroarenes presents an alternative, attractive strategy that could utilize simple nitroarenes as a feedstock. Herein, we report a cationic iridium pre-catalyst and triarylarsine ligands as competent catalyst systems that selectively borylate nitroarenes at the ortho position. This nitro-directed C-H borylation tolerates a wide range of substrates, providing access to diverse ortho-boryl nitroarenes in high yield that can either be isolated directly or reacted without purification to provide functionalized nitroarenes. Finally, we also demonstrate that ortho-boryl nitroarenes can serve as a platform for the synthesis of diverse aromatic products, including in the preparation of 1,2-difunctionalized arenes.