Water → methyl 4-[(1S)-1-[[(2R)-3-methyl-2-(2-phenoxyethoxy)butanoyl]amino]ethyl]benzoate

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Reaction Steps

Under a nitrogen atmosphere, 2-phenoxyethanol (17.3 mL, 138 mmol) in THF (450 mL) is cooled to 5° C. using an ice water bath and treated dropwise over 5 min with a 1M solution of potassium tert-butoxide in THF (138 mL, 138 mmol). The mixture is stirred for 30 min, and methyl 4-[(1S)-1-[[(2R)-3-methyl-2-methylsulfonyloxy-butanoyl]amino]ethyl]benzoate (45 g, 126 mmol) is added in one portion. The mixture is stirred to room temperature for 1 h, and water (300 mL) is added. The layers are separated, and the aqueous layer is extracted with ethyl acetate (100 mL). The combined organic layers are washed with brine, dried over MgSO4, filtered, and concentrated. The crude material is purified using silica gel column chromatography (750 g cartridge; 20 to 60% ethyl acetate in heptane) to provide the title compound as a white solid (30 g, 60%). MS (m/z): 400.4 (M+1).

Provenance & Evidence