Novel ferrocene-based bifunctional amine–thioureas for asymmetric Michael addition of acetylacetone to nitroolefins
Abstract
An efficient method was developed to synthesize ferrocene-based bifunctional amine–thioureas bearing multiple hydrogen-bonding donors. Asymmetric Michael addition of acetylacetone to nitroolefins catalyzed by these novel bifunctional catalysts affords the Michael adducts in high yield and moderate to excellent enantioselectivities. Multiple hydrogen-bonds play an important role in accelerating the reaction.