Iron-Catalyzed Cross-Coupling of Bis-(aryl)manganese Nucleophiles with Alkenyl Halides: Optimization and Mechanistic Investigations

Lidie Rousseau (1, 2) , Alexandre Desaintjean (3) , Paul Knochel (3) , Guillaume Lefèvre (2)

1 LCMCE - Laboratoire de Chimie Moléculaire et de Catalyse pour l'Energie (ex LCCEF)
2 iCLeHS - Institute of Chemistry for Life and Health Sciences
3 Department of Chemistry [München]

Various substituted $bis$-(aryl)manganese species were prepared from aryl bromides by one-pot insertion of magnesium turnings in the presence of LiCl and in situ trans-metalation with MnCl$_2$ in THF at −5°C within 2 h. These $bis$-(aryl)manganese reagents undergo smooth iron-catalyzed cross-couplings using 10 mol% Fe(acac)$_3$ with various functionalized alkenyl iodides and bromides in 1 h at 25°C. The aryl-alkenyl cross-coupling reaction mechanism was thoroughly investigated through paramagnetic $^1$H-NMR, which identified the key role of $tris$-coordinated $ate$-iron(II) species in the catalytic process.

Keywords: iron catalysis; cross-coupling; $bis$-(aryl)manganese; alkenyl halides; $ate$ iron(II) complex

Domains: Chemical Sciences; Material chemistry

Lidie Rousseau, Alexandre Desaintjean, Paul Knochel, Guillaume Lefèvre. Iron-Catalyzed Cross-Coupling of Bis-(aryl)manganese Nucleophiles with Alkenyl Halides: Optimization and Mechanistic Investigations. Molecules, 2020, 25 (3), pp.723. ⟨10.3390/molecules25030723⟩. ⟨cea-02476144⟩