Chiral N,N′-Dioxide/Lanthanide(III) Complex Catalyzed Asymmetric Bisvinylogous Mukaiyama Aldol Reactions

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 alpha-ketoesters and aldehydes, respectively. The catalytic systems were highly epsilon-selective, and the substrate scope was wide. The corresponding epsilon-hydroxy-alpha,beta,gamma,delta-unsaturated esters were obtained in up to 95% yield and 98% ee.