Visible Light‐Mediated Photocatalytic Dearomative Hydroxylation of 2‐aryl‐3‐aryl/Alkyl Indoles

ABSTRACT We have developed a visible‐light‐driven photocatalytic protocol for the efficient synthesis of 3‐hydroxyindolenines under mild reaction conditions. The transformation proceeds via a photocatalytic oxidative process mediated by chlorophyll, which functions as a sustainable, metal‐free, and environmentally benign photocatalyst. Upon irradiation with visible light, chlorophyll is photoexcited to its reactive excited state, enabling effective single‐electron transfer (SET) and/or energy‐transfer pathways that promote the oxidative functionalization of the indole framework. This reaction facilitates selective oxidation at the C3 position of indole substrates, leading to the formation of 3‐hydroxyindolenine derivatives.