Abstract On 1 n, π*-excitation 5, 6-epoxy-2-hydroxy-5, 6-dihydro-β-ionone ((E)-4) shows the typical behaviour of a, β-unsaturated γ, δ-epoxy ketones undergoing primarily C (γ), O- cleavage of the oxiran. However, 1 π, π*-excitation of (E)− 4 leads to enol ether 10 which is formed by intramolecular insertion of the hydroxyl group of the ylide c.
