To an ice-cold solution of 2,2,5,5-tetramethyldihydrofuran-3-one (1.15 g, 0.0081 mol) in 1,2-dimethoxyethane (2 ml) is added sodium methoxide (0.481 g, 0.0089 mol) in one portion. The reaction mixture is then stirred for 5 minutes at this temperature, followed by the addition of a second solution of 2′,4′-dichloro-4-ethylbiphenyl-3-carbaldehyde (2.02 g, 0.0072 mol) in 1,2-dimethoxyethane (2.7 ml). After stirring for an additional 2 hours at 0° C. the reaction mixture is allowed to stand at room temperature overnight. The crude solution is poured into 2M hydrochloric acid and extracted with ether (×3). The organics are combined, washed with brine, dried over magnesium sulfate and concentrated in vacuo. The residue is purified by flash column chromatography (5% ethyl acetate in isohexane to 25% ethyl acetate in isohexane) to afford 4-[1-(2′,4′-dichloro-4-ethylbiphenyl-3-yl)-methylidene]-2,2,5,5-tetramethyldihydrofuran-3-one as a yellow gum.
