Triethylamine → (2R)-2-methanesulfonyloxy-2-((4S)-2-(3-acetoxy-2-methylphenyl)-4,5-dihydrooxazol-4-yl)ethanol

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Reaction Steps

(5R, 6S)-N-(5-Methanesulfonyloxy-2,2-dimethyl-1,3-dioxepan-6-yl)-3-acetoxy-2-methylbenzamide (compound [9], 34.2 g, 82.3 mmol) was dissolved in dichloromethane (340 ml) and boron trifluoride-diethyl ether complex (30.4 ml, 247 mmol) was added over 5 minutes with stirring at room temperature. The mixture was stirred for 40 hours at room temperature. Triethylamine (34.5 ml, 247 mmol) was added at not more than 15° C. and the solvent was distilled away under reduced pressure to ⅕ volume. The residue was diluted with ethyl acetate (340 ml) and washed successively with 10% brine (340 ml), 10% brine (340 ml) containing citric acid (17 g), and saturated brine (340 ml). After drying over magnesium sulfate, the solution was concentrated to 36 g to give a crude product of (2R)-2-methanesulfonyloxy-2-((4S)-2-(3-acetoxy-2-methylphenyl)-4,5-dihydrooxazol-4-yl)ethanol (compound [10]).

Provenance & Evidence