Collect. Czech. Chem. Commun. 1982, 47, 3318-3327

Oxidative rearrangement of o-fuchsone to 2,2-diphenyl-1,3-benzodioxol

Milena Píšová and Milan Souček

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The photo-decolouration of o-fuchsone is caused by [8 + 2] cycloaddition of singlet oxygen to the quinonoid trienone π-system. The arising 1,2,3-trioxanaphthalene undergoes further fragmentations and recyclizations to give 1,3-benzodioxol. The course of this reaction was investigated using fuchsones I-IV as substrates and hydrogen peroxide and tert-butyl hydroperoxide as oxidants. The thermolabile epoxy ketone XV was identified as the key intermediate.