A Highly Stereoselective Synthesis of Chiral α-Amino-β-lactams via the Kinugasa Reaction Employing Ynamides†

A highly stereoselective synthesis of chiral α-amino-β-lactam through an ynamide-Kinugasa reaction is described. In addition, a mechanistic model is illustrated here to rationalize the observed diastereoselectivity, which depends on both the initial [3 + 2] cycloaddition step and the subsequent protonation for which both are highly selective.