Copper-Catalyzed Decarboxylative Propargylic Alkylation of Enol Carbonates: Stereoselective Synthesis of Quaternary α-Amino Acids

Abstract

A copper-catalyzed asymmetric decarboxylative propargylic alkylation of enol carbonates has been realized, allowing for the highly stereoselective formation of acyclic vicinal tri- and tetrasubstituted stereocenters. With this strategy, a series of optically active quaternary α-amino acid esters with an adjunct chiral tertiary propargylic moiety have been prepared from propargyl azlactone-enol carbonates in high yields and with good to excellent diastereo- and enantioselectivities. The success of this reaction exemplifies the high potential of the decarboxylative strategy to resolve unmet challenges present in traditional catalytic propargylic alkylation.