Mechanistic Study of the Jacobsen Asymmetric Epoxidation of Indene.

The asymmetric epoxidation of indene using aqueous NaOCl, catalyzed by Jacobsen's chiral manganese salen complex, provides indene oxide in 90% yield and 85-88% enantioselectivity. The axial ligand, 4-(3-phenylpropyl)pyridine N-oxide (P(3)NO), increases the rate of epoxidation without affecting enantioselectivity and also stabilizes the catalyst. These two effects afford a reduction in catalyst loading to <1%.