Observation of a Photogenerated Rh2 Nitrenoid Intermediate in C-H Amination

Rh-2-catalyzed C-H amination is a powerful method for nitrogenating organic molecules. While Rh-2 nitrenoids are often invoked as reactive intermediates in these reactions, the exquisite reactivity and fleeting lifetime of these species has precluded their observation. Here, we report the photogeneration of a transient Rh-2 nitrenoid that participates in C-H amination. The developed approach to Rh-2 nitrenoids, based on photochemical cleavage of N-Cl bonds in N-chloroamido ligands, has enabled characterization of a reactive Rh-2 nitrenoid by mass spectrometry and transient absorption spectroscopy. We anticipate that photogeneration of metal nitrenoids will contribute to the development of C-H amination catalysis by providing tools to directly study the structures of these critical intermediates.