Sodium acetate (370 mg, 4.5 mmol) was dried in a 100 mL two-necked flask at 150° C. in vacuo for 2 hours, then palladium acetate (100.8 mg 0.45 mmol), copper(II) acetate hydrate (90.0 mg, 0.45 mmol), 3,4-dichloro-N-(4′-fluoro-biphenyl-2-yl)-benzenesulfonamide (3.58 g, 9 mmol), methyl acrylate (2.32 g, 27 mmol), 4 Å molecular sieves (3.6 g) and dimethyl formamide (45 mL) were added, and the resulting mixture was stirred at 120° C. for 16 hours. After cooling the reaction mixture was concentrated, then diluted with water (50 mL) and extracted with diethyl ether (2×30 mL), dried over sodium sulfate, filtered and concentrated. The residue was purified by flash column chromatography using Kieselgel 60 (0.015-0.040 mm) as adsorbent (Merck) and n-hexane:ethyl-acetate=4:1 as eluent to yield 1.91 g (44%) of the title compound as white crystals.
