A series of highly reactive cyclopentadienones were prepared in situ from the corresponding hydroxycyclopent-2-enones and trapped with a variety of quinones. Reaction of 1, 4- naphthoquinone with 4-hydroxy-3, 4-diphenyl-cyclopent-2-enone afforded 2, 3- diphenylanthraquinone, whereas reaction of benzoquinone with this same cyclopentadienone precursor yielded a mixture of 6, 7-diphenyl-1, 4-naphthoquinone and ...