Cobalt(ii)/(imidazoline–oxazoline)-catalyzed enantioselective Michael addition of 2-acetyl azaarenes to β-CF3-β-disubstituted nitroalkenes

Abstract

A series of chiral (imidazoline–oxazoline) N,N-bidentate ligands L1–L5 derived from 2,2-dimethylmalonic acid were conveniently synthesized and characterized. With the aid of the new ligands, the first Co(II)-catalyzed asymmetric Michael addition of 2-acetyl azaarenes to β-CF₃-β-disubstituted nitroalkenes was successfully achieved, producing chiral compounds with a trifluoromethylated all-carbon quaternary stereocenter in good yields with enantioselectivities of up to 98% ee.