Phosphoric acid catalyzed aza-Michael reaction in water has been carried out in an efficient manner at room temperature. The reaction is general for primary, secondary (cyclic, heterocyclic and acyclic), benzylic as well as aromatic amines. No bis-addition was observed for primary amines.
Bandyopadhyay, Debasish; Maldonado, Stephanie; and Banik, Bimal K., "PHOSPHORIC ACID CATALYZED AZA-MICHAEL REACTION IN WATER: AN ECOFRIENDLY PROCEDURE" (2011). Chemistry Faculty Publications and Presentations. 113.