Improving the performance of palladium-catalysed telomerization of 1,3-butadiene by metallocene-based phosphine ligand

By replacing one planar phenyl group of PPh₃ with bulkier ferrocenyl or ruthenocenyl group, the performance of resulted metallocene-based phosphine ligand in the telomerization of 1,3-butadiene with methanol has been largely elevated compared to the widely used PPh₃. High catalytic efficiency with good selectivity has been obtained under the conditions of high butadiene-to-palladium ratio, low catalyst concentration and relatively low temperature. The advantages of ruthenocenyl phosphine ligand on tolerating alkene impurity and stable regioselectivity under different circumstances has been demonstrated. DFT computations have been conducted and elucidate the origin of such drastically improved performance from the simple change on the substituent of phosphine ligand.