Green Aza-Michael Reaction of Aliphatic Amines to á,(a)-Unsaturated Compounds in Water

The hydroamination of olefins is a long-standing goal for transition metal catalysis. And the metal-catalyzed addition of amines to carbon-carbon double bonds is an unsolved, synthetically important problem. Although recent advances have made using lanthanide and precious metal complexes, there are few excellent catalyst that display broad functional group tolerance and useful rates for an intermolecular aza-Michael addition. As such, the development of efficient synthetic methods leading to a-amino carbonyl compounds and derivatives has attracted much attention in organic synthesis. Although recent advances have made this route more attractive, development of cheaper, simpler, and more efficient metal catalyst is highly desirable. We also have been interested in developing a reaction that uses catalytic quantities of minimally toxic, readily available, economic reagent should greatly contribute to the creation of environmental benign processes.The recent interest in aqueous medium metal-mediated carbon-carbon and carbon-heteroatom and formations led to the contributors for such reactions. Furthermore, development of organic reactions in water will contribute to the progress of green and quasi-nature catalysis chemistry. Surprisingly however, there is few report on conjugate additions of amines to a,a-unsaturated carbonyl compounds in water.Herein, we report a new protocol that employs air stable copper salts as efficient catalyst in the aza-Michael reaction under mild reaction conditions. Advantages of the protocol include high-yielding reactions that can be conducted at ambient temperature; the use of readily available and stable copper salts as the catalyst, and the reaction was successfully performed in environmental benign solvent, water.Finally, we have utilized a variety of aliphatic amines successfully with different á,(a)-unsaturated compounds catalyzed by simple hydrophilic ionic liquid, bmimBF4 in water. Interestingly, all the aliphatic amines gave almost quantitative in yield with á,(a)-ethylenic compounds. The present reactions with its mild reaction conditions open a novel entry to synthesis of a-amino carbonyl compounds by simple procedure.