Construction of β to carbonyl stereogenic centres by asymmetric 1,4-addition of alkylzirconocenes to dienones and ynenones.

Copper-catalyzed asymmetric 1,4-addition of alkylzirconium species to linear α,β,γ,δ unsaturated dienones and ynenones is reported. A variety of alkyl nucleophiles are introduced with good yields and excellent regio- and enantio-selectivities to give tertiary carbon centres bearing multiple functional groups. The method is also applicable to an ynethioate with ee's over 96%.