Catalytic Asymmetric Vinylation of Ketones

This communication describes the catalytic asymmetric 1,2-addition of vinylzinc reagents to aromatic, alpha,beta-unsaturated, and dialkyl ketones with enantioselectivities between 79 and 97% and with yields ranging from 84 to 98%. The products of these reactions are tertiary allylic alcohols with chiral quaternary centers that are useful in organic synthesis. The reaction involves hydrozirconation of a terminal alkyne, transmetalation to zinc, and addition to a ketone in the presence of a chiral titanium-based Lewis acid catalyst. The reactions proceed smoothly at room temperature in under 24 h.