Trisimidazolines in Asymmetric Conjugate Additions

Significance

The authors report the straightforward synthesis of trisimidazoline 1 and its catalytic application in the conjugate addition of β-keto ­esters to nitroolefins. The products were obtained in high yields and diastereo- and enantio­selectivities. The authors proposed different hydrogen-bonding activation modes, out of which the dual activation of the keto ester and the nitro-styrene seems to be most likely. The origin of enantioselectivity, the C ₃ symmetry of the catalyst, is presumed to efficiently preorganize the ­reactants.