Catalytic Asymmetric Michael Reaction of 5H-Oxazol-4-Ones with α,β-Unsaturated Acyl Imidazoles.

The asymmetric Michael reaction between 5H-oxazol-4-ones and α,β-unsaturated acyl imidazoles is reported. A novel 2-benzo[b]thiophenyl-modified chiral ProPhenol species is synthesized and used as a ligand, leading to good enantioselectivities in this asymmetric conjugate addition reaction. Furthermore, the introduction of phenol additives as achiral co-ligands is found to improve the reaction's chemical yields, diastereoselectivities, and enantioselectivities.