Aryl-X Bond-Forming Reductive Elimination from High-Valent Mn-Aryl Complexes

C-X bond reductive elimination and oxidative addition are key steps in many catalytic cycles for C-H functionalization catalyzed by precious metals; however, engaging first row transition metals in these overall 2e(-) processes remains a challenge. Although high-valent Mn aryl species have been implicated in Mn-catalyzed C-H functionalization, the nature and reactivity of such species remain unelucidated. In this work, we report rare examples of stable, cyclometalated monoaryl Mn-III complexes obtained through clean oxidative addition of Ar-Br to Mn-1(CO)(5)Br. These isolated Mn-III-Ar complexes undergo unprecedented 2e(-) reductive elimination of the Ar-X (X = Br, I, and CN) bond and Mn-II induced by 1e(-) oxidation, presumably via transient reactive Mn-IV species. Mechanistic studies suggest a nonradical pathway.