Organocatalytic aza-Michael-Michael cascade reactions: a flexible approach to 2,3,4-trisubstituted tetrahydroquinolines.

Cascading like dominos: An efficient and highly enantioselective synthesis of 2,3,4-trisubstituted tetrahydroquinolines through cascade aza-Michael-Michael reactions was developed. Tetrahydroquinolines were obtained in excellent yields, high enantioselectivities, and good diastereoselectivities, and could be easily transformed into ring-fused tetrahydroquinolines (see scheme).