Iodine → (E)-tert-Butyl 2-(2-methoxyethoxymethyl)-3-(benzenesulphonyl)acrylate

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To a suspension of benzenesulphinic acid sodium salt (7.59 g, 46.2 mmol) and tert-butyl 2-(2-methoxyethoxymethyl)acrylate (10.0 g, 46.2 mmol) in ethyl acetate (50 mL) under a nitrogen atmosphere at room temperature was added, in one portion, iodine (11.3 g, 46.2 mmol) and the mixture stirred for 3 days. An additional 50 mL of ethyl acetate was added after 2 days. The reaction mixture was cooled to 0° C. and triethylamine (9.67 mL, 69.3 mmol) added dropwise. The reaction was stirred at 0° C. for 2 hours and at room temperature for 16 hours and diluted with distilled water (100 mL) and ethyl acetate (50 mL). The layers were separated and the aqueous layer further extracted with ethyl acetate (25 mL). The combined ethyl acetate extracts were washed with a 1.0M aqueous hydrochloric acid solution and 5% aqueous sodium thiosulphate solution (2×100 mL), filtered to remove solids and the filter pad washed with ethyl acetate. The combined filtrate and washings were washed with distilled water (50 mL), and concentrated under reduced pressure to give a brown oil, (14.85 g). The crude product was purified by chromatography on silica by eluting with hexane/ethyl acetate (2:1) to give, after combination and evaporation of appropriate fractions, the title compound as an oil, (5.09 g, 30.8%) which crystallised on standing, m.pt.=46°-48° C., Rf =0.25 (silica, hexane/ethyl acetate, 2:1), (MH+ 357.05, 1.7%).

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