Combined Synthetic, Spectroscopic, and Computational Insights Into a General Method for Photosensitized Alkene Aziridination

Aziridines are important targets for synthetic chemistry, and many methods involving the aziridination of alkenes by olefins with nitrenes have been reported. In general, however, nitrene transfer reactions are optimized for a limited range of nitrene precursors, and the synthesis of structurally diverse aziridines featuring a range of N-substituents requires the application of multiple methods with varying reaction conditions. Herein, we report a photocatalytic method for the aziridination of olefins that operates with a wide range of N-substituted nitrene precursors. A combination of synthetic, spectroscopic, and computational data is consistent with a mechanism involving the photocatalytic generation of triplet nitrene intermediates. The effectiveness of 4DPAIPN as a photocatalyst for this process can be rationalized as a consequence of its exceptionally long lifetime, rather than of its excited state energies or redox properties in isolation.