Photochemische Reaktionen 119. Mitteilung [1] Zur Photospaltung konjugierter γ,δ-Epoxyenone. UV.-Bestrahlung von 3-(1′,2′-Epoxy-2′-methyl-prop-1′-yl)-5,5-dimethyl-2-cyclohexen-1-on

Photocleavage of Conjugated π,π-Epoxyenones. UV.-Irradiation of 3-(1′,2′-Epoxy-2′-methyl-prop-1′-yl)-5,5-dimethyl-2-cyclohexene-1-one On ¹π,π*-excitation (δ = 254 nm) 9 undergoes cleavage of the C(δ), C(δ)-bond yielding 17 and a , which gives 18 by photofragmentation. In presence of maleinic ester the photolysis of 9 yields 20 , in presence of methanol 21 and 22 are obtained. By photocleavage of the C(δ), O-bond 9 is converted into b giving 14 . Photolysis of 14 yields 15 ( A + B ) and 16 . On ¹n,π*-excitation (δ λ? 347 nm) of 9 cleavage of the C(δ), O-bond ( 9 → b ) seems to be the preferred reaction, whereas products of a are formed in traces, only.