1,8-Diazabicyclo(5.4.0)undec-7-ene → HCID 69853422, compound

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Reaction Steps

A solution of [2-(4-benzyl-2-oxo-oxazolidin-3-yl)-2-oxo-ethyl]-phosphonic acid diethyl ester (36.72 g) in dry acetonitrile (550 ml) was stirred at room temperature under nitrogen and treated with lithium chloride (4.39 g) followed by the dropwise addition of 1.8-diazabicyclo (5.4.0) undec-7-ene (g, mmol). After 5 minutes, the crude 4-benzyl-2,2-dimethyl-(2-oxo-ethyl)-oxazolidine-3-carboxylic acid tert-butyl ester dissolved in dry acetonitrile (350 ml) was added via a cannula, and the resulting mixture was stirred at room temperature for 80 minutes. The mixture was then diluted with diethyl ether (1 L) and washed with brine (500 ml). The organic layer was dried (anhydrous magnesium sulfate) and concentrated in vacuo . Purification by flash chromatography on silica gel (ethyl acetate/hexane: 1/4 to 3/7) provided of 4-benzyl-5-[4-(4-benzyl-2-oxo-oxazolidin-3-yl)-4-oxo-but-2-enyl]-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester (29.33 g, 69%).

Provenance & Evidence