Enantioselective Michael Addition of Malononitrile to Unsaturated Ketones Catalyzed by Rare-Earth Metal Amides RE[N(SiMe3)2]3 with Phenoxy-Functionalized TsDPEN Ligands

The catalytic enantioselective Michael addition of a,ss-unsaturated ketones with malononitrile was well established using rare-earth metal amides RE[N(SiMe3)2] 3 (RE = Y, Eu, Sm, Nd, La) with chiral phenoxy-functionalized TsDPEN ligands. The combination of lanthanum amide La[N(SiMe3)2] 3 and chiral TsDPEN ligand H3L1 [H3L1 = N-((1R,2R)-2-((3,5-di-tert-butyl-2-hydroxybenzyl) amino)-1,2-diphenylethyl)-4- methylbenzenesulfonamide] in a 1:1.5 molar ratio was proved to be the optimal partner in THF, which provided the desired ss-carbonyl dinitriles in excellent yields and good to high enantioselectivities after 12 h at -15 degrees C.

Automated summary

The catalytic enantioselective Michael addition of α,β-unsaturated ketones with malononitrile was successfully achieved using rare-earth metal amides and chiral phenoxy-functionalized TsDPEN ligands. The optimal reaction conditions provided the desired products in excellent yields and good to high enantioselectivities.