A novel oxidative free radical reaction between 2-hydroxy-1,4-naphthoquinone and β-enamino carbonyl compounds

The manganese(III) initiated oxidative free radical reaction between 2-hydroxy-1,4-naphthoquinone and β-enamino carbonyl compound 2 is described. Enamine radical 5 can be generated effectively from the oxidation of enamine 2 by manganese(III) acetate. Spirolactam 3 was prepared effectively from readily available 2-hydroxy-1,4-naphthoquinone and enamine 2.