Barium-Catalyzed Mannich Reaction-Isomerization Sequence

Significance

Reported here is one of the rare examples of efficient use of β,γ-unsaturated esters as nucleophiles in a direct Mannich reaction. Products of Mannich reaction isomerize to give aza-Morita-Baylis-Hilman-type compounds in good yields and with a high level of diastereoselectivity. In addition, the authors have also performed this reaction sequence in the presence of a chiral ligand and obtained products with good ee values.