Superior effect of a π-acceptor ligand (Phosphine-Electron-Deficient olefin ligand) in the Negishi coupling involving alkylzinc reagents

[GRAPHICS] Palladium-catalyzed Negishi cross-coupling involving primary and secondary alkyls, even in the presence of beta-H, can be achieved at ambient temperature using chelating ligands containing a phospline and an electron-deficient olefin. The superior effects of the ligands were shown not only in the desired cross-coupling product yields but also in the fast reaction at mild conditions. This reaction has been also scaled up to 50 g in 0.005 mol % catalyst (20,000 TONs) at room temperature.