An unusual caged oxetan formed by intramolecular photocyclization onto the carbonyl group of a polyalicyclic enedione

Abstract

p-Benzoquinone reacts with 1,4-dimethyl-2,3-diphenylcyclopentadiene and the similarly substituted cyclopentadienone to form exclusively the endo adducts (12) and (9) respectively. Photocyclization of these adducts in the solid state yields the respective cyclobutyl photocage compounds (10) and (13).Photolysis of the dienone adduct (9) in solution yields an unusual oxetan product (14) resulting from cyclization between a carbonyl group of the enedione and the proximate olefinic π-centre, as well as the normal cage product (10).