Accessing Heterocycle‐Containing Borazine Frameworks via C−H Functionalization Reactions of Heterocycles

The structural diversity of borazine‐based frameworks falls far behind that of their all‐carbon aromatic counterparts, particularly in the direct incorporation of heterocyclic moieties, largely due to the absence of reliable methods. To overcome this limitation, we herein report a versatile strategy for the synthesis of previously inaccessible heterocycle‐containing borazines using an iodinated hexaarylborazine as an electrophilic coupling partner. A dual Pd/Cu cooperative catalytic system was developed to enable the efficient and selective installation of a diverse range of five‐membered and benzo‐fused heterocycles onto borazine scaffolds. This methodology represents the first general approach in which heterocycles undergo direct C–H functionalization to be installed onto the hexaarylborazine cores, thereby significantly expanding both the structural and electronic diversity accessible within BN‐doped aromatic systems. More broadly, this work establishes a new postfunctionalization strategy for borazine diversification and provides access to structurally complex borazine architectures, thereby opening new opportunities for the design and development of functional BN‐doped materials.