Abstract On irradiation in the presence of dye sensitizers, vinylogous epoxy carbonyl compounds undergo a novel photofragmentation reaction, to give furyl ketones in good yields. The fragmentation process is probably preceded by trans-cis isomerization of the double bond; in one case the cis-isomer could be isolated. In a side reaction epoxyenone 10 gives the cyclopentanone derivatives 13 and 14 by a [1, 2] shift of a methyl group.
