Observation of a Photogenerated Rh Nitrenoid Intermediate in C-H Amination.

Rh-catalyzed C-H amination is a powerful method for nitrogenating organic molecules. While Rh 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 nitrenoid that participates in C-H amination. The developed approach to Rh nitrenoids, based on photochemical cleavage of N-Cl bonds in N-chloroamido ligands, has enabled characterization of a reactive Rh 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.