Organocatalytic Diastereo- and Enantioselective Michael Addition of α-Aryl Isocyanoacetates to Aurone-Derived Azadienes

A highly diastereo- and enantioselective organocatalytic Michael addition of α-aryl isocyanoacetates to aurone-derived azadienes under mild conditions has been developed. This efficient methodology enables access to chiral α,α-disubstituted α-amino ester derivatives with two adjacent stereocenters, one of them quaternary, bearing a benzofuran scaffold in their structure in high yields and stereocontrol. Furthermore, the reaction product can be readily converted into an α,α-disubstituted α-amino acid in high yield via hydrolysis of the isocyano group without compromising enantioselectivity.