Irradiation of o-alkylphenyl 1,3-diketones (1) in hexane gave benzocyclobutenols (2) which underwent thermal retro-aldol cleavage to yield benzocyclobutenones (3).
Irradiation of 3-hydroxy-1-(o-methylaryl)-2,2,4-trimethylpentan-1-ones 1 in methanol gave cyclopropane-1,2-diols 2, 1,3-diketones 3 and benzocylobutenols 4.