A selective gold(I)-catalyzed synthesis of chiral aza-proline derivatives has been developed by ring closure of enantioenriched α-hydrazino esters bearing an alkyne group. These are easily prepared through a synthetic strategy involving two key steps: organocatalyzed electrophilic amination of pent-4-ynal with dialkyl azodicarboxylate promoted by l-proline and functionalization of the triple bond by