“…Over the past two decades, the direct chalcogenation of C-H bonds has evolved as a straightforward, atom-and step-economical method for the preparation of chalcogenated compounds including organyl sulfides, selenides, sulfones, trifluoromethylthioethers, thiocyanates and selenocyanates. [57][58][59][60][61][62][63][64] A variety of transition-metal-catalyzed/mediated chelationassisted C-H chalcogenation, along with directing group-free C-H chalcogenation of electron-rich (hetero)arenes and deprotonative chalcogenation of electron-deficient (hetero)arenes 65 have been reported through transition-metal-catalyzed/ mediated, 58,59,[66][67][68][69] metal-free, 29,[70][71][72][73] photocatalytic or electrochemical 60,63 approaches. For instance, in 2017, Ackermann and coworkers disclosed a copper-catalyzed chelation-assisted C2-H chalcogenation (S, Se) of indoles and C7-H chalcogenation (S, Se) of indolines with diaryl dichalcogenides through an additive-free approach under aerobic reaction conditions.…”