Iodine → Tert-butyl 4-oxooct-7-enylcarbamate

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Reaction Steps

While under an atmosphere of nitrogen, a flame-dried round-bottomed flask was charged with magnesium (3.95 g, 0.162 mol) a small crystal of I2 and just enough dry THF to cover the magnesium. The mixture was heated to reflux until the color dissipated (about 10 min.). Next, a solution of 4-bromo-1-butene (16.4 mL, 0.162 mmol) in dry THF (70 mL) was added and heating was continued for 10 min. After cooling to room temperature, the newly formed Grignard reagent was then added to a ice-cooled solution of tert-butyl 4-(methoxy(methyl)amino)-4-oxobutylcarbamate (10 g, 0.041 mol) in dry THF (100 mL). After stirring overnight at room temperature, the solution was poured into saturated aqueous ammonium chloride (70 mL) and extracted with ether (2×). The organic extracts were combined and washed successively with 1.0 M aq HCl and sat'd aq sodium chloride, dried over MgSO4, filtered and concentrated. Purification by flash column chromatography (15-30% ethyl acetate in hexanes) gave tert-butyl 4-oxooct-7-enylcarbamate as a colorless oil (6.04 g, 62%). ESI MS found for C13H23NO3 m/z [264.3 (M+Na+)].

Provenance & Evidence