[F:1][C:2]1[CH:10]=[CH:9][C:5]([C:6](Cl)=[O:7])=[CH:4][CH:3]=1.C=[O:12].[CH2:13]([Cl:15])Cl>[Cl-].[Cl-].[Cl-].[Cl-].[Zr+4]>[F:1][C:2]1[CH:10]=[CH:9][C:5]([C:6]([O:12][CH2:13][Cl:15])=[O:7])=[CH:4][CH:3]=1(Mudryk, B. et al., Tetrahedron Lett. 2002, 43, 6317-6318) 4-Fluorobenzoyl chloride (3.0 g, 18.9 mmol) was added to a stirred suspension of zirconium tetrachloride (4.0 g, 17.01 mmol) in dry CH2Cl2 (40 mL) at room temperature. After 15 min, the reaction mixture was cooled to 0° C. and paraformaldehyde (0.68 g, 22.7 mmol) was added. The slurry was stirred at 0-25° C. for 2 h and the solvent was removed under vacuum. Water (50 mL) was added slowly and the mixture was agitated for 10 min. The aqueous layer was extracted with EtOAc (3×50 mL). The combined organic phase was washed with 1 N sodium bicarbonate (2×50 mL) followed by brine (1×30 mL). The solvent was removed and the product was purified by silica gel chromatography (5% EtOAc-Hexanes). Yield 3.2 g (89%). 1H NMR (500 MHz, CDCl3): δ 5.86 (s, 2H), 7.06 (m, 2H), 8.02 (m, 2H).
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