Visible‐Light‐Induced 3‐ <i>H</i> Indole Hydrogenation for Indoline Synthesis Catalyzed by Thioxanthone‐TfOH Complex

ABSTRACT Imine hydrogenation is a fundamental transformation in organic synthetic methodology. Although numerous methods have been developed, imine reduction protocols with inert solvent hydrogen source are still unrealized. In this work, a strategy of photocatalytic imine hydrogenation with 9‐HTXTF (thioxanthone‐TfOH complex) serving as the photocatalyst and p ‐xylene serving as the hydrogen source was thoroughly investigated. This strategy, with its reaction conditions optimized, substrate scope examined, and reaction mechanism explored, provides an efficient method for synthesizing indoline derivatives.