Decarboxylation\nof Aza-Annulation\nProducts as a Synthetic\nRoute to 3‑Pyrrolin-2-ones and 1,2,3,4-Tetrahydropyridin-2-ones

Aza-annulation\nof enamines derived from β-ketoesters with\nmaleic and itaconic anhydrides proceeds with excellent diastereoselectivity\nto provide functionalized γ- and δ-lactams. Further hydrolysis\nof the aza-annulation products resulted in dicarboxylic acids that\nunderwent spontaneous decarboxylation under ambient conditions. The\ndecarboxylation of β–γ unsaturated carboxylic acids\nwith an electron-rich enamide CC bond proceeds with the migration\nof the CC bond and serves as a practical synthetic entry into\n3-pyrrolin-2-ones and 1,2,3,4-tetrahydropyridin-2-ones.