Tetrahydrofuran → tert-Butyl 3-{[(4S)-benzyl-2-oxo-1,3-oxazolidin-3-yl]carbonyl}-6-cyclohexylhexanoate

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Reaction Conditions

Reaction Steps

A solution of (4S)-4-benzyl-3-(5-cyclohexylpentanoyl)-1,3-oxazolidin-2-one (70.0 g, 204 mmol anhydrous tetrahydrofuran (650 ml) was cooled to −70° C. and treated dropwise with sodium hexamethyldisilazide (1M in tetrahydrofuran, 224 ml, 224 mmol) over 45 minutes. The mixture was stirred for a further 45 minutes before being treated with t-butylbromoacetate (31.6 ml, 214 mmol). This mixture was stirred at −70° C. for 30 minutes then warmed to −30° C. and quenched with an aqueous solution of ammonium chloride (20% w/v, 400 ml) and warmed to room temperature. The mixture was extracted with ethyl acetate and the combined organic extracts were washed with brine, dried over anhydrous sodium sulphate and the solvent removed under reduced pressure. The solid was recrystallised from hexane to afford the title compound as a white solid (71.4 g).

Provenance & Evidence