Unveiling the Unique\nReactivity of Anionic Mn(I) Complexes\nvia Metal–Ligand Cooperation: Nucleophilic Attack on C(sp<sup>3</sup>)–X Bonds

Metal–ligand cooperation (MLC) has emerged as\na pivotal\nstrategy for the catalytic activation of small molecules within both\nsynthetic and biological arenas. Leveraging this approach, a suite\nof potent catalytic reactionsencompassing hydrogenation, hydroelementation,\nand dehydrogenative processeshave been realized, with notable\nadvances in manganese catalysis in recent years. However, the activation\nof alkyl halides by Mn complexes, which typically requires strong\nreductants to form Mn(–I) complexes that are incompatible with\nstandard cross-coupling conditions, remains a significant challenge.\nThis limitation underscores the urgent need to investigate alternative\nmethods for activating C(sp<sup>3</sup>)–X bonds using higher\nvalence state Mn complexes. In response to this challenge, we present\nthe synthesis, characterization, and reactivity of a new anionic Mn(I)\ncomplex featuring a redox-active dianionic ligand that induces multiple\nMLC functionalities. We have discovered an innovative mechanism of\nMLC, characterized by a single ligand transferring two electrons to\nthe metal center. This novel process facilitates an orbital-symmetry-allowed\nnucleophilic attack on C(sp<sup>3</sup>)–X bonds, preserving\nmanganese’s oxidative state at +1. To the best of our knowledge,\nthis is the first instance where the MLC strategy via a two-electron\ntransfer process has been utilized to execute an S<sub>N</sub>2 nucleophilic\nattack at a C(sp<sup>3</sup>)–X bond by a relatively electron-deficient\nmetal center like Mn(I). Additionally, the dianionic ligand of the\nanionic Mn(I) complex exhibits ambident nucleophilicity by reacting\nwith different electrophiles, further highlighting its versatile reactivity.