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  • A manganese catalyst for hi...
    Paradine, Shauna M; Griffin, Jennifer R; Zhao, Jinpeng; Petronico, Aaron L; Miller, Shannon M; Christina White, M

    Nature chemistry, 12/2015, Volume: 7, Issue: 12
    Journal Article

    C-H bond oxidation reactions underscore the existing paradigm wherein high reactivity and high selectivity are inversely correlated. The development of catalysts capable of oxidizing strong aliphatic C(sp(3))-H bonds while displaying chemoselectivity (that is, tolerance of more oxidizable functionality) remains an unsolved problem. Here, we describe a catalyst, manganese tert-butylphthalocyanine Mn((t)BuPc), that is an outlier to the reactivity-selectivity paradigm. It is unique in its capacity to functionalize all types of C(sp(3))-H bond intramolecularly, while displaying excellent chemoselectivity in the presence of π functionality. Mechanistic studies indicate that Mn((t)BuPc) transfers bound nitrenes to C(sp(3))-H bonds via a pathway that lies between concerted C-H insertion, observed with reactive noble metals such as rhodium, and stepwise radical C-H abstraction/rebound, as observed with chemoselective base metals such as iron. Rather than achieving a blending of effects, Mn((t)BuPc) aminates even 1° aliphatic and propargylic C-H bonds, demonstrating reactivity and selectivity unusual for previously known catalysts.