Abstract: 4-Carbomethoxy-4-vinyl-2, 5-cyclohexadien-l-ones 6a and 6b were prepared from methyl benzoate and methyl 2-methoxybenzoate in 45% overall yields. Irradiation of 6a in benzene solution at 366 nm gave 2-carbomethoxybicyclo-[32* 3-4.26* 7. 1]-2, 6-octadien-9- 0ne (7, 35%), 2-carbomethoxybicyclo [3.3. 01* 5]-2, 7-octadien-6-one (8, 8%), and 4- carbomethoxy-3-vinylphenol (9, 39%). The structure of phenol 9 was confirmed by ...