Synthesis of masked haloareneboronic acids via iridium-catalyzed aromatic C–H borylation with 1,8-naphthalenediaminatoborane (danBH)

“Masked” areneboronic acids have been prepared by Ir-catalyzed C–H borylation of arenes. A [Ir(OMe)(cod)]2 complex with a DPPE ligand showed the highest catalytic activity in the C–H borylation of benzene at 80 °C. The reaction system can be applied to substituted arenes, including halogen-substituted arenes. 1,3-Dihalobenzenes undergo the C–H borylation at their 5-positions in a regioselective fashion, affording 3,5-dihaloareneboronic acid derivatives, which serve as useful coupling modules for the convergent dendrimer synthesis.