“…The ability of Pd(II) to activate C-H bonds through chelation-assisted processes has been known since the 1960s. Nitrogen-containing directing groups were found to promote the insertion of palladium into an ortho-C-H bond, which led to the formation of stable and isolable cyclopalladated complexes from Pd(II) starting material (Scheme 6) [25,[31][32][33][34][35][36][37][38][39][40]. Despite the large literature devoted to the synthesis of various palladacycles and studies of their reactivity, their redox properties, which are necessary to describe and understand the mechanisms of catalytic reactions involving them, are elucidated only in few works [11,15,24,25,[41][42][43][44].…”