Catalytic asymmetric allylations of achiral and chiral aldehydes via BINOL–Zr complex

The complex generated from BINOL, Zr(OtBu)4, and 4 Å MS in toluene–pivalonitrile is very effective for catalytic asymmetric allylation of aldehydes using allyltributyltin. The reactions of achiral aldehyde under these conditions are completed within 3 h using 10–20 mol% of the complex at −20°C. The ees of homoallylic alcohols can be enhanced up to 98% via the tandem asymmetric allylation–Oppenauer oxidations. The scope and limitations of these conditions for β-alkoxy aldehydes were extensively examined.