On the Mechanistic Behavior of Highly Efficient Palladium−Tetraphosphine Catalytic Systems for Cross-Coupling Reactions: First Spectroscopic and Electrochemical Studies of Oxidative Addition on Pd(0)/Multidentate Ferrocenylpolyphosphine Complexes

Transmetalation from Magnesium–NHCs—Convenient Synthesis of Chelating π-Acidic NHC Complexes

The synthesis of chelating N-heterocyclic carbene (NHC) complexes with considerable π-acceptor properties can be a challenging task. This is due to the dimerization of free carbene ligands, the moisture sensitivity of reaction intermediates or reagents, and challenges associated with the workup procedure. Herein, we report a general route using transmetalation from magnesium–NHCs. Notably, this route gives access to transition-metal complexes in quantitative conversion without the formation of byproducts. It therefore produces transition-metal complexes outperforming the conventional routes based on free or lithium-coordinated carbene, silver complexes, or in situ metalation in dimethyl sulfoxide (DMSO). We therefore propose transmetalation from magnesium–NHCs as a convenient and general route to obtain NHC complexes.

Cyclopalladated complexes containing 2-C6R4PPh2 ligands (R = H, F): one-electron electrochemical reduction leading to metal–carbon σ-bond cleavage via palladium(i)

Cyclopalladated complexes containing the 2-C₆F₄PPh₂ fragment have been prepared and their electrochemical reduction behaviour investigated.