Photochemische Reaktionen. 95. Mitteilung. Zur Photochemie konjugierter Epoxy‐enone: Die UV.‐Bestrahlung von 9‐Isopropyl‐6‐methyl‐9, 10‐epoxybicyclo [4.4.0] dec‐1‐en‐3‐on

The Photochemistry of Conjugated Epoxy‐enones: Photolysis of 9‐Isopropyl‐6‐methyl‐9,10‐epoxybicyclo [4.4.0]dec‐l‐en‐3‐on The title compound 1 undergoes on π, π*‐excitation vinylogous β‐cleavage of the C(γ), O‐bond and isomerizes to the unsaturated 1, 5‐diketone 8 (58%) and the tricyclic diketone 9 (14%). On n, π*‐excitation, however, 1 undergoes only desoxygenation to the dienone 7 (ca. 15%) besides polymerization. UV.‐irradiation of 1 (λ ≥ 347 nm) in the presence of tributyl‐stannane gives 7 in 85% yield; in the presence of tributylstannane‐d 1 1 yields 13 , the deuterated analogon of 7 (85% yield; d 1 ca. 50%); 7 has been proven to be stable on π, π* ‐ as well as on n, π*‐excitation.