University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 1 1 1989 12 01 Photochemical Rearrangement of 8- methyl Spiro [2.5] oct-7-en-4-one to 4-methyl Spiro [2.5] oct-4-en-6-one - 31170 EN Journal Article Irradiation of &methyl spiro [2.5] oct-7-en-4-one through its singlet excited state resulted in the formation of 4-methyl spirO [2.5] oct-4-en -6-one. We have used the cyclopropyl moiety in the molecule as a probe to study the operating mechanism in the photochemistry of ?, ?-unsaturated compounds. The results showed that this photoisomerization probably occurs through a concerted process. https://jsciences.ut.ac.ir/article_31170_93a819cbd635bd1505ef0f804c21cc2a.pdf