Iron-Catalyzed Cross-Coupling: Mechanistic Insight for Rational Applications in Synthesis

Abstract

Iron-catalyzed cross-coupling reactions provide a promising way to form new carbon–carbon bonds and build up molecular complexity. This short review presents recent advances in the synthetic application of these reactions as well as in the elucidation of their mechanism. It also highlights remaining problems and aims at pointing out ways toward possible remedies.1 Introduction2 Synthesis: Recent Accomplishments and Unsolved Problems2.1 Substrate Scope: Electrophiles2.2 Substrate Scope: Nucleophiles2.3 Catalyst Activity and Chemoselectivity2.4 Stereoselectivity2.5 Practical Aspects3 Mechanism: Recent Insights and Open Questions3.1 Transmetallation and Activation of the Iron Precatalyst3.2 Coupling via Oxidative Addition and Reductive Elimination3.3 Coupling via C–X Bond Homolysis and Radical Rebound3.4 Coupling via Bimolecular C–X Bond Homolysis3.5 Other Reactions of Organoiron Species with Electrophiles4 Toward Rational Reaction Improvement5 Conclusion