Catalytic Asymmetric Synthesis of α-Alkenyl Quaternary Amino Acid Esters

Although chiral α-alkenyl quaternary amino acid derivatives have been extensively utilized in organic synthesis, the catalytic asymmetric synthesis of such compounds remains elusive. In this report, we present a highly efficient method for the direct introduction of an alkenyl group at the α carbon of an NH₂-unprotected amino acid ester through a three-component reaction involving readily available aryl (alkenyl) bromide and allyl acetate, facilitated by chiral aldehyde/palladium co-catalysis. A diverse array of α-alkenyl quaternary amino acid esters featuring unconjugated π systems are generated in commendable yields and excellent enantioselectivities, and some of them are used for the synthesis of valuable building blocks.