Highly Diastereo‐ and Enantioselective Reactions of Enecarbamates with Ethyl Glyoxylate To Give Optically Active syn and anti α‐Alkyl‐β‐Hydroxy Imines and Ketones

The remarkably selective addition of enecarbamates 2 to ethyl glyoxylate (1) in the presence of a copper–diimine catalyst (0.1 mol %) gives the corresponding imines 3 in high yields with excellent enantioselectivities. A concerted aza-ene-type reaction mechanism was proposed to explain the stereochemical outcome.