Enantioselective Catalytic Domino Aza‐Michael–Henry Reactions: One‐Pot Asymmetric Synthesis of 3‐Nitro‐1,2‐dihydroquinolines via Iminium Activation

Asymmetric transformations arising from iminium activation of aromatic aldehydes are uncommon. In this work, an enantioselective organocatalytic domino aza‐Michael–Henry reaction between N ‐(2‐formylphenyl)sulfonamides and trans ‐β‐nitro olefins through iminium activation has been presented. This reaction proceeded smoothly to give chiral 3‐nitro‐1,2‐dihydroquinolines in high yields with up to 88 % ee under mild conditions. Furthermore, a preliminary study showed that 2‐mercaptobenzaldehyde derivatives could participate in a thia‐Michael–Henry reaction with trans ‐β‐nitro olefins to yield chiral 3‐nitro‐2 H ‐thiochromenes.