反应详情

To (E)-(2S,3S,4S,5S)-3,5-Dimethoxy-2,4-dimethyl-oct-6-en-1-ol (1.5 g, 6.94 mmol) in anhydrous pyridine (20 ml) at 0° C. and under an atmosphere of nitrogen was added pivaloyl chloride (1.33 ml, 10.7 mmol). The reaction was warmed to room temperature and stirred for 2 hours, after which it was quenched with saturated ammonium chloride and extracted with dichloromethane (2×). 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, 20:1 then 1:1) to afford 2.0 g (100%) as a clear oil. 1H NMR (300 MHz, CDCl3) δ 5.67 (dq, J=15.3 Hz, 6.6 Hz, 1H), 5.21 (m, 1H), 4.23 (dd, J=10.6 Hz, 3.3 Hz, 1H), 4.1 (dd, J=10.6 Hz, 6.0 Hz, 1H), 3.52 (dd, J=10.0 Hz, 2.0 Hz, 1H), 3.42 (s, 3H), 3.34 (t, J=9.3 Hz, 1H), 3.25 (s, 3H), 1.96 (m, 1H), 1.78 (dd, J=6.4 Hz, 1.5 Hz, 3H), 1.68 (m, 1H), 1.24 (s, 9H), 0.90 (d, J=7.1 Hz, 3H), 0.76 (d, J=7.1 Hz, 3H).

1. customafter which it was quenched with saturated ammonium chloride
2. extractionextracted with dichloromethane (2×)
3. customThe combined organic layers were dried
4. concentrationconcentrated in vacuo
5. customThe product was purified by flash chromatography (SiO2
6. customiHex/EtOAc, 20:1 then 1:1) to afford 2.0 g (100%) as a clear oil