Dimethyl Carbonate → Methyl 4-oxooxane-3-carboxylate
Reaction equation
[O:1]1[CH2:6][CH2:5][C:4](=[O:7])[CH2:3][CH2:2]1.[CH3:8][O:9][C:10](=O)[O:11]C.CC(C)([O-])C.[K+]>>[CH3:8][O:9][C:10]([CH:3]1[C:4](=[O:7])[CH2:5][CH2:6][O:1][CH2:2]1)=[O:11]Participants
4
Procedure
To a solution of tetrahydro-pyran-4-one (1.3 kg, 12.98 mol) and carbonic acid dimethyl ester (11.69 kg, 129.8 mol) was added solid potassium tert-butoxide (1.89 kg, 16.08 mol) in portions at −10° C. over 2 h under nitrogen protection. The suspension was stirred at room temperature 10 h after the addition. LCMS (215 nm) indicated that tetrahydro-pyran-4-one had been completely consumed. The reaction was acidified by HCl (2 N) to pH 6˜7 and then the phases were separated. The organic phase was washed with water (3 L×2) and the combined aqueous phases were extracted with MTBE (2.5 L×2). The combined organic phase was concentrated under reduced pressure at 25° C. to remove most of MTBE. The residue was distilled out by oil pump (˜200 Pa) at 74° C. to give the title compound as colorless oil (545 g, 26.3%). CHN analysis: calculated (results). C, 53.16 (53.10), H, 6.37 (6.245), N, 0.00 (0.00).