Three-Component Synthesis of γ-Amino Esters with α-Quaternary Carbon Centers via NHC/Photoredox Dual Catalysis.

γ-Amino acid derivatives are important motifs in medicinal chemistry and have shown wide applicability as inhibitory neurotransmitters. An important class of these compounds feature α,α-disubstitution. However, established routes for the direct synthesis of γ-amino esters bearing α-quaternary centers are severely limited in both number of available routes and scope of the transformation. Herein we present a method for the three-component synthesis of α,α-disubstituted γ-amino esters via NHC/photoredox dual catalysis. This reaction involves formation of an acyl azolium ester which undergoes photocatalytic reduction to the key stabilized alkoxycarbonyl radical. This methodology was shown to be capable of synthesizing a wide variety of γ-amino esters with various α-quaternary centers in moderate to good yields, including a derivative of the drug loperamide. The diversity of products that can be synthesized facilitates the rapid generation of libraries of γ-amino acid derived compounds.)).