Friedel-Crafts acylation of 2,4-dimethylresorcinol (I) with sorbic acid (II) in the presence of boron trifluoride etherate provided, after aqueous hydrolysis of the intermediate boron complex, ketone (III). Subsequent oxidative treatment with lead tetraacetate furnished the desired alpha-acetoxy dienone (IV) along with minor amounts of its regioisomer (V). After chromatographic separation, dimerization of dienone (IV) using CsOH produced a mixture of the title [4+4] adduct and the [4+2] adduct (VI). The compounds were separated by flash column chromatography.