Hydrochloric Acid → (S)-benzyl 5-(1,3-dioxoisoindolin-2-yl)-1-hydroxypentan-2-yl(methyl)carbamate

Beteiligte Stoffe

Reaktionsschritte

To a solution of (S)-benzyl 4-(3-(1,3-dioxoisoindolin-2-yl)propyl)-5-oxooxazolidine-3-carboxylate (11.6 g, 28.40 mmol) in DCM (30.0 mL) was added Et3SiH (13.6 mL, 85.3 mmol). The reaction mixture was stirred overnight, concentrated under reduced pressure, and dissolved in THF (100 mL). To the resulting solution was added tert-butyl chloroformate (4.4 mL, 34.08 mmol) and TEA (12.0 mL, 85.2 mmol) at 0° C. The reaction mixture was stirred at RT for 30 min. The precipitate was filtered off and the filtrate was added into a suspension of NaBH4 in water (1.0 mL) at 0° C. The reaction mixture was stirred at RT for 30 min. LCMS indicated the completion of the reaction. The reaction mixture was acidified to pH 3 by HCl (1N) and extracted with EtOAc (300 mL×2). The combined organic layers were washed with saturated NaHCO3 and brine, dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified on silica gel using a mixture of EtOAc and hexanes to give (S)-benzyl 5-(1,3-dioxoisoindolin-2-yl)-1-hydroxypentan-2-yl(methyl)carbamate (5.01 g, 45%). LRMS (M+H+) m/z 397.3.

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