(2R)-2-Bromopropanoic acid → (S)-2-(Acetylthio)-propanoic Acid

Participants

Reaction Steps

To a light green solution of potassium thioacetate (3.94 g, 34.5 mmol) in acetonitrile (150 ml) was added a solution of (R)-2-bromopropanoic acid (4.8 g, 31 mmol) in acetonitrile (12 ml) at room temperature under an argon atomosphere. The resulting white slurry was stirred at room temperature for 2 hours then filtered. The filtrate was concentrated in vacuo. The residue was diluted in ethyl acetate (100 ml), washed with a 10% aqueous solution of potassium bisulfate (50 ml) and brine, dried (sodium sulfate), and concentrated in vacuo. The crude product (4.61 g) was purified by flash chromatography (60 g - Merck silica gel, 1:45:54 acetic acid/ethyl acetate/hexane) to afford 3.7 g of the title product as a light yellow oil; [α]D =-114° (c=0.50, methanol).

Provenance & Evidence