Dimethoxymethane → (3R,5S)-5-[(R)-2-Benzyloxy-1-hydroxyethyl]-3-propyldihydrofuran-2-one

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Reaction Steps

400 ml of a solution of a sodium tetraborate buffer solution (0.05 M) in a 0.4 mM disodium ethylenediaminetetraacetate aqueous solution, 0.600 g of tetrabutylammonium bisulfate (1.77 mmol) and 10.3 g of 1,2:4,5-di-O-isopropylidene-β-D-erythro-2,3-hexodiuro-2,6-pyranose (39.9 mmol) were added to 10.5 g of (2R,4E)-6-benzyloxy-2-propylhex-4-enoic acid obtained in Example (116b) (40.0 mmol) in a mixed solvent of acetonitrile (150 ml) and dimethoxymethane (300 ml) at room temperature, and the mixture was stirred for 10 minutes. The reaction mixture was cooled in an ice bath. Then, a solution of 34.0 g of Oxone (trade mark) (55.2 mmol) in a 0.4 mM disodium ethylenediaminetetraacetate aqueous solution (200 ml) and a solution of 31.8 g of potassium carbonate (230 mmol) in water (200 ml) were separately added dropwise over seven hours. The mixture was stirred at the same temperature for one hour and then diluted with 200 ml of water, followed by extraction with ethyl acetate. Then, the organic layer was washed with brine and dried over anhydrous magnesium sulfate. After filtration, the solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (elution solvent:n-hexane/ethyl acetate=6/1-1/1) to obtain 7.30 g of the title compound (total yield over two steps: 66%).

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