Diethyl Oxalate → Ethyl 5-methyl-3-oxohexanoate

Participants

Reaction Conditions

Reaction Steps

Sodium pellets (4.6 g, 200 mmol) were dissolved in ethanol (165 ml) under nitrogen at room temperature and a solution of diethyloxalate (13.5 ml, 100 mmol) in isobutylmethyl ketone (30 ml, 200 mmol) was added dropwise at room temperature over 20 minutes. The reaction was heated to 60° C. and stirred at this temperature for one hour. After cooling to room temperature the reaction was poured onto ice-cold 2N HCl (200 ml) and extracted with diethylether (4×200 ml). The combined organic extracts were washed with water, dried over MgSO4 and concentrated under reduced pressure to give 5-methyl-3-oxo-hexanoic acid ethyl ester (20 g) as a yellow oil. 1H NMR (400 MHz, CDCl3): δ=14.40-14.70 (1H, brs), 6.27 (1H, s), 4.25-4.32 (2H, quart), 2.26-2.31 (2H, d) (1H, m), 1.29-1.34 (3H, t), 0.89-0.94 (6H, d) ppm. LRMS (thermospray): m/z [M+NH4]+ 218.

Provenance & Evidence