Sulfoxonium, trimethyl-, iodide (1:1) → Ethyl 1-[2,6-bis(methoxymethoxy)-3-methyl-phenyl]cyclopropanecarboxylate

To a solution of trimethylsulfoxonium iodide (4.4 g, 20 mmol) in dry dimethyl sulfoxide (30 mL) sodium hydride (60% dispersion in mineral oil) (0.720 g, 18 mmol) was added and the reaction mixture was stirred for 1 hour at room temperature. A solution of ethyl 2-[2,6-bis(methoxymethoxy)-3-methyl-phenyl]prop-2-enoate (Intermediate 9, 3.5 g, 11.29 mmol) in dry dimethyl sulfoxide (15 mL) was slowly added and the reaction mixture was stirred for 1 hour at room temperature. The reaction was quenched with an aqueous saturated solution of ammonium chloride (10 ml), diluted with water (40 ml) and extracted with ethyl acetate (2×100 ml). The organic layer was washed with water (2×50 ml), dried over sodium sulphate, filtered and evaporated. The residue was purified by flash chromatography (Biotage system) on silica gel using a 100 g SNAP column and cyclohexane to cyclohexane/ethyl acetate 8:2 as eluents affording the title compound (3.1 g) as a colourless oil.