Trifluoroacetic Acid-Mediated Oxidative Self-Condensation of Acetophenones in the Presence of SeO2: A Serendipitous Approach for the Synthesis of Fused [1,3]Dioxolo[4,5‑d][1,3]dioxoles

A method for the synthesis of fused 1,3-dioxolanes was developed by self-condensation of glyoxal generated in situ by oxidation of acetophenones with SeO2 in the presence of trifluoroacetic acid. Three molecules of the glyoxal generated by oxidation of ketone with SeO2 condensed to form architecturally novel oxygen-containing heterocycles (3a-aryldihydro-[1,3]­dioxolo­[4,5-d]­[1,3] dioxole-2,5-diyl)­bis­(phenylmethanones). This reaction provides a unique methodology for the construction of four C–O bonds in a concerted fashion, generating highly embedded oxygen heterocycles from readily available ketones using affordable shelf reagents and simple reaction conditions.