Acceleration of the conjugate addition of diethyl zinc to enones by either Cu(OTf)2 or trivalent phosphorus ligands

Article abstract of DOI:10.1016/S0040-4039(97)10068-5

The conjugate addition of diethyl zinc to enones under copper catalysis occurs well with copper (II) trifiate. Other copper salts need a phosphine or phosphite ligand to be efficient. The best combination is copper (II) triflate and triethyl phosphite. A very small amount of copper (II) triflate (0.5%) and triehtyl phosphite (1%) are enough for high yields.