One-Pot Catalytic Enantioselective Synthesis of Functionalized Tetrahydroquinolines by Aza-Michael/Michael Cascade Reactions of N-Protected 2-Aminophenyl α,β-Unsaturated Esters with Nitroolefins

A highly enantioselective synthesis of functionalized tetrahydroquinolines with useful biological properties has been developed by means of asymmetric organocatalytic aza-Michael/Michael cascade reactions of nitroolefins with N-protected 2-aminophenyl α,β-unsaturated esters in the presence of a chiral thiourea catalyst. The reaction gave the corresponding highly functionalized tetrahydroquinolines in good yields, excellent diastereoselectivities (>30:1 dr), and high enantioselectivities (≤99% ee).