Diastereoselective synthesis of α,β-unsaturated systems

Functionalized Z-vinylic tellurides were used in substitution reactions with lower order cyanocuprates leading to α,β-unsaturated ketones and esters in good yields. In the case of acyclic tellurides, the product was obtained in high diastereoselectivity. The control of the stereoselectivity was achieved by simple change of the reaction temperature.