Visible‐light photoredox catalysis offers a promising approach to convert indoles into functionalized indoles and indolines under mild conditions. However, existing methods often rely on iridium or ruthenium polypyridyl photocatalysts, which suffered from sustainability concerns and limited scope. Here, we report a transition‐metal‐free protocol for diverse indole transformations using catechol‐derived organic photocatalysts that feature balanced redox potentials and broad reactivity. Three mechanistically distinct transformations of indoles including aerobic bromination, dearomative carbamoylation, and dearomative reduction or detosylation have been achieved under net oxidative, redox‐neutral, and net reductive conditions, respectively. A variety of bromoindoles, carbamoyl‐indolines, and functionalized indolines or free N–H indoles are obtained in good yields under mild, transition‐metal‐free conditions. This article provides a sustainable and versatile entry to indole transformations.
Huang et al. (Tue,) studied this question.