反应详情

To 2,2-Dimethyl-propionic acid (2S,3S,4R,5R)-3,5-dimethoxy-2,4-dimethyl-hept-6-ynyl ester (750 mg, 2.64 mmol) in anhydrous methanol (10 ml) at room temperature and under an atmosphere of nitrogen was added sodium methoxide (30% wt in MeOH, 3.8 ml, 21.1 mmol). The reaction was stirred overnight, quenched with saturated ammonium chloride and extracted with dichloromethane (3×). The combined organic layers were dried by passing through a hydrophobic frit and concentrated in vacuo. The product was purified by flash chromatography (SiO2, iHex/EtOAc, 6:1 then 2:1) to afford 500 mg (94%) as a clear oil. 1H NMR (300 MHz, CDCl3) δ 3.86 (dd, J=9.4 Hz, 2.1 Hz, 1H), 3.75-3.60 (m, 2H), 3.49 (s, 3H), 3.48 (m, 1H), 3.46 (s, 3H), 2.59 (m, 1H), 2.49 (d, J=2.1 Hz, 1H), 2.03-1.84 (m, 2H), 1.04 (d, J=7.0 Hz, 3H), 0.90 (d, J=7.0 Hz, 3H).

1. customquenched with saturated ammonium chloride
2. extractionextracted with dichloromethane (3×)
3. customThe combined organic layers were dried
4. concentrationconcentrated in vacuo
5. customThe product was purified by flash chromatography (SiO2, iHex/EtOAc, 6:1
6. custom2:1) to afford 500 mg (94%) as a clear oil