title: Isolation, Characterization, and Reactivity of Fe8Me12(-): Kochi's S = 1/2 Species in Iron-Catalyzed Cross-Couplings with MeMgBr and Ferric Salts.
abstract: Iron-catalyzed cross-couplings with simple ferric salts have been known since the 1970s, pioneered by Kochi for cross-coupling using alkylmagnesium nucleophiles including MeMgBr. While Kochi observed the formation of a S = 1/2 iron species in reactions of simple ferric salts with MeMgBr proposed to be an iron(I) species, the identity of this species has remained undefined for nearly 40 years. Herein, we report the isolation and characterization of [MgCl(THF)5][Fe8Me12], which combined with EPR and MCD studies is shown to be consistent with Kochi's S = 1/2 species. Reaction studies with β-bromostyrene demonstrate that this species alone displays minimal reactivity but, when combined with additional MeMgBr, leads to rapid and selective formation of cross-coupled product.
authors.affiliation: Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Salvador B
authors.initials: SB
authors.lastname: Muñoz Iii
authors.affiliation: Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Daifuku
authors.affiliation: Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
authors.forename: William W
authors.initials: WW
authors.lastname: Brennessel
authors.affiliation: Department of Chemistry, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Neidig
mesh_terms: D001965:Bromides / Q000737:chemistry*; D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry / Q000302:isolation & purification*; D004578:Electron Spin Resonance Spectroscopy; D005290:Ferric Compounds / Q000737:chemistry*; D005663:Furans / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry*; D008745:Methylation; D013343:Styrenes / Q000737:chemistry
chemical_list: D001965:Bromides; D056831:Coordination Complexes; D005290:Ferric Compounds; D005663:Furans; D017616:Magnesium Compounds; D013343:Styrenes; C018238:beta-bromostyrene; C586611:magnesium bromide; C018674:tetrahydrofuran; D007501:Iron