A Type of Stable Amides Behaves as Acyl Transfer Reagents upon Visible‐Light Irradiation through Self‐aromatization

Organic molecules with light‐modifiable reactivity are important in many fields because they can serve as the “switch” for light to trigger chemical processes. Herein, we disclose a new type of stable non‐twisted amides, the reactivity of which can be turned on by light as acyl transfer reagents. Upon photo‐activation, these amides react with various nucleophiles including amines, phenols, hydroxide, thiols, boronic acids, and alkynes either under metal‐free or metal‐catalysis conditions. This reactivity hinges on the design and synthesis of a photo‐activatable reagent (7‐nitro‐5,6‐dihydrophenanthridine), which undergoes self‐aromatization enabled by an internal oxidant under light. This masked acyl donor group is anticipated to be useful in scenarios where light is preferred to trigger a chemical process.