Stereodivergent access to non-natural α-amino acids via enantio- and <i>Z</i> / <i>E</i> -selective catalysis

The precise control of <i>Z</i> and <i>E</i> configurations of the carbon-carbon double bond in alkene synthesis has long been a fundamental challenge in synthetic chemistry, even more pronounced when simultaneously striving to achieve enantioselectivity [(<i>Z</i>,<i>R</i>), (<i>Z</i>,<i>S</i>), (<i>E</i>,<i>R</i>), (<i>E</i>,<i>S</i>)]. Moreover, enantiopure non-natural α-amino acids are highly sought after in organic and medicinal chemistry. In this study, we report a ligand-controlled stereodivergent synthesis of non-natural α-quaternary amino acids bearing trisubstituted alkene moieties in high yields with excellent enantioselectivity and <i>Z</i>/<i>E</i> selectivities. This success is achieved through a palladium/copper-cocatalyzed three-component assembly of readily available aryl iodides, allenes, and aldimine esters by simply tuning the chiral ligands of the palladium and copper catalysts.