The UV irradiation of 2, 4, 6-tri-t-butyl-4-hydroxy-2, 5-cyclohexadienone (I) in petroleum ether yielded the diketone V (11%) and the enedione VII (54%) in addition to the cyclopentenone VIII (3%) and the bicyclopentanone X (8%). The formation of V and VII can be rationalized by considering a common intermediate, the lumi-type ketone III. This result indicates that 4-hydroxy-2, 5-cyclohexadienones undergo photorearrangement similar to ...
