Thiophenol → (S)-tert-butyl 4-oxo-2-(pent-4-enamido)-4-(phenylthio)butanoate

Participants

Reaction Steps

DIC (2.43 ml, 15.6 mmol), DMAP (318 mg, 2.60 mmol) and benzenethiol (1.59 ml, 15.6 mmol) were added to a solution of the mixed crude product A (2.53 g, 13.0 mmol) of (S)-4-(tert-butoxy)-4-oxo-3-(pent-4-enamido)butanoic acid (Compound 1b-I) and pent-4-enoic acid (1:0.8) in CH2Cl2 (35 ml), and the mixture was stirred at room temperature for 4 hours. The reaction mixture was filtered, and the resulting filtrate was concentrated, diluted with ethyl acetate and then washed with a saturated aqueous ammonium chloride solution, saturated aqueous sodium bicarbonate and brine. The organic extract was then dried over magnesium sulfate and concentrated under reduced pressure. The resulting residue was purified by reverse-phase silica gel column chromatography (10 mM aqueous ammonium acetate solution/methanol=70/30→0/100), and the resulting crude product was further purified by silica gel column chromatography (hexane/ethyl acetate=100/0→65/35) to afford (S)-tert-butyl 4-oxo-2-(pent-4-enamido)-4-(phenylthio)butanoate (Compound 1e-IF) (1.99 g, 79%).

Provenance & Evidence