Photoactive Iminobismuthanes for Catalytic C-H Amination

Metal-nitrenoids are employed in the direct amination of ubiquitous carbon-hydrogen bonds. Traditionally, their synthetic utility has relied on the redox flexibility and the coordinative reactivity of the metal center, conferred by the d-orbitals. Here, we demonstrate that bismuth─a main-group element lacking accessible frontier d-orbitals─can nevertheless exhibit catalytic activity analogous to that of transition-metal systems. When an iminobismuthane is subjected to light irradiation, a ligand-to-ligand charge transfer ensues, leading to C-H bond abstraction and C-N bond formation. The unique electronic properties of bismuth permit complementary reactivity beyond that of transition metals, as exemplified by the azidation of unprotected secondary amines. This work reveals main-group imidos as catalytically competent species, rather than merely precursors in transition-metal catalysis.