Oxalic Acid → (S)-2-(4-fluoro-phenyl)-2,3-dihydro-1H-pyridin-4-one

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Reaction Steps

To a solution of 2-(4-fluoro-phenyl)-4-oxo-5-triisopropylsilanyl-3,4-dihydro-2H-pyridine-1-carboxylic acid 5-methyl-2-(1-methyl-1-phenyl-ethyl)-cyclohexyl ester (7.78 g, 12.8 mmol) in methanol (95 mL) was added 25% sodium methoxide in methanol (29.4 mL, 128.4 mmol). The mixture was heated at reflux for 16 h. After cooling to rt, oxalic acid (46.3 g, 512 mmol) was added and the mixture was stirred for 2 h. The solvent was evaporated to dryness. The crude was partitioned between ethyl acetate and water. The organic layer was washed with water, brine dried over MgSO4, filtered and concentrated to dryness. Purification by flash chromatography (hex:EtOAc/2:8-0:1) gave (S)-2-(4-fluoro-phenyl)-2,3-dihydro-1H-pyridin-4-one (0.886 g, 36%, ee 99.3%) as a yellow solid.

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