Chiral Nanoparticles/Lewis Acids as Cooperative Catalysts for Asymmetric 1,4-Addition of Arylboronic Acids to alpha,beta-Unsaturated Amides

摘要

Cooperative catalysts consisting of chiral Rh/Ag nanoparticles and Sc(OTf)(3) have been developed that catalyze asymmetric 1,4-addition reactions of arylboronic acids with alpha,beta-unsaturated amides efficiently. The reaction has been considered one of the most challenging reactions because of the low reactivity of the amide substrates. The new catalysts provide the desired products with outstanding enantioselectivities (>98% ee) in the presence of low loadings (< 0.5 mol%) of the catalyst.