55. Photocatalytic Anti-Markovnikov Hydroamination of Alkenes with Primary Heteroaryl Amines
Eric P. Geunes, Jonathan M. Meinhardt, Emily J. Wu, and Robert R. Knowles
J. Am. Chem. Soc. 2023, 145, 40, 21738–21744. DOI: 10.1021/jacs.3c08428
Abstract: We report a light-driven method for the intermolecular anti-Markovnikov hydroamination of alkenes with primary heteroaryl amines. In this protocol, electron transfer between an amine substrate and an excited-state iridium photocatalyst affords an aminium radical cation (ARC) intermediate that undergoes C–N bond formation with a nucleophilic alkene. Integral to reaction success is the electronic character of the amine, wherein increasingly electron-deficient heteroaryl amines generate increasingly reactive ARCs. Counteranion-dependent reactivity is observed, and iridium triflate photocatalysts are employed in place of conventional iridium hexafluorophosphate complexes. This method exhibits broad functional group tolerance across 55 examples of N-alkylated products derived from pharmaceutically relevant heteroaryl amines.