Highly enantioselective synthesis of (E)-allylic alcohols

The asymmetric addition of alkenylzincs to aromatic and alpha-branched aliphatic aldehydes catalyzed by 1 generated the corresponding (E)-allylic alcohols with >95% ee and good to excellent chemical yields, especially >99.5% ee was observed in the case of 4-CF3-benzaldehyde. Notably, 1 is an effective ligand to catalyze the addition of disubstituted (R2 = R3 = ethyl) and bulky substituted (R2 = H, R3 = tert-butyl) alkenylzincs to benzaldehyde, affording the corresponding allylic alcohols both with 96% ee.