Abstract Irradiation 1, 1, 2, 2-tetraarylcyclopropanes with trifluoroacetic acid in the presence of oxygen produced 3, 3, 5, 5-tetraaryl-1, 2-dioxolanes. This reaction is initiated by the single electron transfer from cyclopropanes to excited carbenium ions which are formed by sequential ring opening and light absorption of protonated cyclopropanes.
