“…Ever since, various other ligands have been investigated in scandium-catalyzed Michael additions of b-ketoesters, malonates, hydroxylamines, or thiols to a,bunsaturated carbonyl compounds, among which N,N 0 -dioxides [14], pybox derivatives [15], and BNP ligands [16]. As a recent example, Liu and Feng developed asymmetric scandiumcatalyzed Michael additions of malonates 2a-d to enynes 18a-s to give the corresponding chiral functionalized trisubstituted allenes 19a-v, as shown in Scheme 6 [17]. The reaction was performed in the presence of a combination of Sc(OTf) 3 and chiral N, N 0 -dioxide 20 that allowed products 19a-v to be formed in impressive enantioselectivities of 97-99% ee along with good to almost quantitative yields of 61-98% and moderate to high diastereoselectivities of 56-90% de.…”