Direct Catalytic Enantioselective Aza‐Diels–Alder Reactions

Proline and its derivatives catalyze the asymmetric one-pot three-component aza-Diels–Alder reaction between unmodified α,β-unsaturated cyclic ketones, aqueous formaldehyde, and aryl amines with excellent chemo- and enantioselectivities (see scheme). Furthermore, this reaction provides a highly enantioselective entry to bicyclic non-proteogenic amino acid derivatives.