Diisopropylamine → tert-Butyl N-allyl-N-(2-isothiazol-5-yl-2-oxo-ethyl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a −78° C. solution of diisopropylamine (9.01 mL, 64.01 mmol) in tetrahydrofuran (80 mL) is added n-butyl lithium (30.78 mL, 49.24 mmol, 1.6 M in hexanes) drop wise under nitrogen. The resulting solution is stirred at −78° C. for 20 minutes and then a solution of isothiazole (4.19 g, 49.24 mmol) in tetrahydrofuran (10 mL) is added drop wise. The resultant white slurry is stirred for 30 minutes at −78° C. A solution of tert-butyl N-allyl-N-[2-(methoxy(methyl)amino)-2-oxo-ethyl]carbamate (6.36 g, 24.62 mmol) in tetrahydrofuran (50 mL) is then added to the slurry over a 15 minutes period. The reaction is then stirred for 30 minutes at −78° C., warmed to ambient temperature and is stirred for 30 minutes. Saturated ammonium chloride (200 mL) is then added. The resulting solution is extracted three times with ethyl acetate. The combined organic layers are dried over sodium sulfate, filtered, and concentrated under vacuum. The crude product is purified over silica gel with a 35 minute, 5% to 100% ethyl acetate in hexanes gradient, to give the title compound (6.00 g, 21.25 mmol, 86%). ES/MS (m/e): 283.0 (M+H).

Provenance & Evidence