Development of Chiral Pincer Palladium Complexes Bearing a Pyrroloimidazolone Unit. Catalytic Use for Asymmetric Michael Addition

Novel pincer palladium complexes having chiral hexahydro-1H-pyrrolo[1,2-c]imidazolone groups were designed and prepared. Catalytic asymmetric Michael addition of isopropyl 2-cyanopropionate to ethyl vinyl ketone was catalyzed by the chiral pincer palladium complex to give isopropyl 2-cyano-2-methyl-5-oxoheptanoate with high enantioselectivity (up to 83% ee).