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An asymmetric vinylogous Mukaiyama-Michael reaction of α,β-unsaturated 2-acyl imidazoles catalyzed by chiral Sc(iii)- or Er(iii)-pybox complexes.

A highly diastereo- and enantioselective vinylogous Mukaiyama-Michael reaction of silyloxyfurans with α,β-unsaturated 2-acyl imidazoles catalyzed by either chiral Sc(iii) or Er(iii) complexes of a pybox ligand has been reported. The enantioenriched γ-butenolides formed in the reaction were further transformed into highly functionalized γ-lactones found as important structural frameworks in a wide range of biologically active natural products.