Visible-light-mediated amination reactions via nitrene intermediates

Photochemistry is a classic discipline in chemistry, and applications date back to the beginning of the 20 th century, featuring light as the energy source. In organic synthesis, photochemistry takes up an exceptional role to access reactive intermediates, and the past decades have witnessed the development of major milestones and concepts, for example, in the utilization of radicals under photoredox or carbenes under photochemical conditions. Contrarily, the access and application of nitrenes under photochemical conditions remains largely underestimated. Nitrenes are monovalent, nitrogen-based reactive intermediates and are of prime importance for applications in modern drug discovery and agrochemistry. Typically, the pivotal nitrene intermediate is accessed under metal-catalyzed conditions requiring forcing reaction conditions, such as high reaction temperature or harsh oxidants that limit potential applications. In the past years, several groups reported on photochemical applications to open up new paradigms in amination reactions via nitrene intermediates, which will be discussed in this perspective. Challenges and opportunities • Photochemistry and photocatalysis open up new avenues in nitrene chemistry via free nitrene or nitrene radical anion intermediates and facilitate amination reactions at room temperature. • Photochemistry and photocatalysis provide opportunities to overcome challenges in classic metal-catalyzed nitrene transfer reactions. • Photochemistry allows the access of metal-nitrene complexes under mild conditions to study their fundamental properties and their application in amination reactions. Photochemistry and -catalysis open up approaches toward amination reactions that overcome classic limitations of metal-catalyzed traditional nitrene transfer reactions. This perspective discusses recent advances in this research area that allow the development of amination reactions under mild conditions, with or without the need of classic nitrene transfer catalysts.