Bifunctional guanidine via an amino amide skeleton for asymmetric Michael reactions of beta-ketoesters with nitroolefins: a concise synthesis of bicyclic beta-amino acids.

Two activations are better than one: The chiral bifunctional guanidine 1, which features an amino amide backbone, catalyzes the asymmetric Michael addition of a range of substrates and gives products with excellent stereoselectivities. The method also allows the efficient synthesis of optically pure beta-amino acid esters. Both the guanidine group and the NH proton of the amide were important for the dual activation.