N-Heterocyclic Carbene-Catalyzed Chemo- and Enantioselective Three-Component Esterification/Amidation Relay for Access to Planar Chiral Ferrocene Derivatives

An N-heterocyclic carbene (NHC)-catalyzed three-component esterification/amidation relay strategy was disclosed for facile access to enantio-enriched planar chiral ferrocene derivatives. The esterification and amidation reactions in the catalytic relay proceeded in sequence in both chemoselective and enantioselective fashions. Both experimental and computational methods were used to reveal the reaction mechanism and indicated that both the hydrogen-bonding (H-bonding) interactions and the basic additives in the catalytic system had played crucial roles in the reaction chemo- and stereoselectivities. The planar chiral ferrocene-based ester-amide products showed interesting applications in the synthesis of multiple novel ligands for asymmetric catalysis and the development of chiral bactericides for crop protection.