Water → methyl 7-[(1R,2R,3R,5S)-5-acetoxy-2-((E)-4,4-difluoro-3-oxo-1-octenyl)-3-(2-tetrahydropyranyloxy)cyclopentyl]heptanate

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Reaction Steps

To a solution uf dimethyl (3,3-difluoro-2-oxoheptyl)phosphonate (1) (1.109 g, 4.295 mmol) in t-butyl methyl ether (17 ml), sodium hydroxide (0.164 g, 4.10 mmol) was added and the mixture was stirred for approximately 1.2 hours at room temperature. A solution of methyl 7-[(1R,2R,3R,5S)-5-acetoxy-2-formyl-3-(2-tetrahydropyranyl-oxy)cyclopentyl]heptanate (2) (0.955 g, 2.40 mmol) in t-butyl methyl ether (3 ml), and water (0.32 ml) were added thereto, and the mixed solution was heat refluxed for approximately 48 hours. After cooling to room temperature, water (5.6 ml) was added to the solution and stirred, arid then, let to stand and separated into two layers. The aqueous layer was extracted twice with ethyl acetate (4 ml). The organic layers were combined, sequentially washed with 3% aqueous sodium chloride (6 ml) and saturated aqueous sodium chloride (6 ml), and then dried with anhydrous magnesium sulfate. After concentration under reduced pressure, the residue was purified by silica gel column chromatography (Fuji Silysia BW-300SP: 33 g; ethyl acetate:hexane=1:4) to give methyl 7-[(1R,2R,3R,5S)-5-acetoxy-2-((E)-4,4-difluoro-3-oxo-1-octenyl)-3-(2-tetrahydropyranyloxy)cyclopentyl]heptanate (3) (1.079 g; 2.033 mmol; yield: 84.8%).

Provenance & Evidence