文摘
Chiral N,N′-dioxide/Y(OTf)3 and Sc(OTf)3 complexes have been developed as efficient catalysts for the bisvinylogous Mukaiyama aldol reaction of silyl ketene acetal with α-ketoesters and aldehydes, respectively. The catalytic systems were highly ε-selective, and the substrate scope was wide. The corresponding ε-hydroxy-α,β,γ,δ-unsaturated esters were obtained in up to 95% yield and 98% ee.