Methyl (S)-2-benzyloxycarbonylamino-3-chlorocarbonylpropionate → Methyl (S)-2-benzyloxycarbonylamino-4-oxopentanoate

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Reaction Conditions

Reaction Steps

To a cooled to 0° C. suspension of copper (I) iodide in ether (20 mL) under N2 is slowly added methyl lithium (1.6 M solution in ether, 21.3 mmol, 13.3 mL). The mixture is stirred at 0° C. for 10 min then cooled to −78° C. A solution of 3.55 mmol of (S)-2-Benzyloxycarbonylamino-3-chlorocarbonyl-propionic acid methyl ester (Ref: Synth. Comm 1993, 23(18), 2511-2526) in 12 mL of dry THF is added drop wise. The mixture is stirred at −78° C. for 30 min then quenched by adding methanol (2 mL). The mixture is poured into saturated NH4Cl (80 mL) and extracted with ether (2×40 mL). The organic layers are dried over magnesium sulfate and concentrated in vacuum. The residue is purified over 35 g silica gel, eluted with EtOAc:Heptane (1:1) to afford (S)-2-benzyloxycarbonylamino-4-oxo-pentanoic acid methyl ester (261 mg, 26%).

Provenance & Evidence