Late-Stage Functionalization of 1,2-Dihydro-1,2-azaborines via Regioselective Iridium-Catalyzed C-H Borylation: The Development of a New N,N-Bidentate Ligand Scaffold

The first general late-Stage functionalization of monocyclic. 1,2-azaborines at the C(6) position is described. Ir-catalyzed C-H borylation occurs regioselectively at the C(6) position of B-substituted 1,2-azaborines and is compatible with a range of substitution patterns at boron (e.g., hydride, alkoxide, alkyl, and aryl substituents). Subsequent Suzuki cross coupling with aryl- and heteroaryl bromides furnishes, 1,2,azaborine-based-biaryl compounds including 6,-[pyrid-2-yl]-1,2-azaborines that represent novel kappa(2)-N,N-bidentate ligands. The 6-[pyrid-2-yl]-B-Me-1,2-azaborine ligand has been demonstrated. to form an emissive coordination complex with dimesitylboron that exhibits bathochromically shifted absorption and emission maxima, and a higher photoluminescence quantum yield compared to its carbonaceous analogue.