Asymmetric aza-Michael reactions catalyzed by cinchona alkaloids.
The organocatalysed asymmetric aza-Michael addition of hydrazones to cyclic enones has been achieved in good yield and stereoselection using cheap and commercially available cinchona alkaloids as catalysts. A systematic study of the influence of the structure of the enone on the stereoselectivity was carried out, leading to optically active products with up to 77% ee. The products can be recrystallized to give nearly enantiopure products, and furthermore it was shown that the products could be reduced to the corresponding 1,3-benzylidenehydrazino alcohol derivatives with high diastereoselectivity.
Perdicchia
Dario
D
Danish National Research Foundation, Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
Jørgensen
Karl Anker
KA
D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D002930:Cinchona Alkaloids / Q000737:chemistry*; D006835:Hydrazones / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
D002930:Cinchona Alkaloids; D006835:Hydrazones