Visible Light‐Induced Ru‐Catalyzed Directing‐Group‐Assisted C−H Activation of Arenes

Abstract Ru‐catalyzed directing group assisted C−H functionalization of arenes remains one of the powerful tools for site selective organic synthesis. Previous thermos versions normally require high temperature, rendering low functional group tolerance. With the emergence of the photoredox chemistry, visible light mediated mild Ru‐catalyzed directed C−H activation, especially using [RuCl 2 ( p ‐cymene)] 2 as catalyst, have recently been investigated. Meta , ortho , and para selectivity have been achieved owing to the different activation mode of ruthenium complex. Inner‐sphere electron transfer and outer‐sphere electron transfer redox processes were attributed to different reaction pathway. In this review, we will provide an overview on recent achievements in visible light mediated Ru‐catalyzed directed C−H activation of arenes.