反应详情

p-Toluenesulfonic acid monohydrate (29 mg, 0.15 mmol) and 3,4-dihydro-2H-pyran (99%, 205 μL, 2.39 mmol) were sequentially added to a suspension of C1 (250 mg, 1.49 mmol) and 4 Å molecular sieves in dichloromethane (10 mL). The reaction mixture was allowed to stir at room temperature for 4 hours, at which time it was filtered, concentrated in vacuo, and washed three times with heptane. Purification via silica gel chromatography (Gradient: 20% to 50% ethyl acetate in heptane) afforded the product as a colorless oil. Yield: 65 mg, 0.26 mmol, 17%. LCMS m/z 252.1 [M+H+]. 1H NMR (400 MHz, CDCl3), characteristic peaks: δ 8.08 (d, J=0.9 Hz, 1H), 7.26-7.27 (m, 1H), 5.67 (dd, J=9.1, 2.8 Hz, 1H), 3.99-4.05 (m, 1H), 3.71-3.79 (m, 1H), 2.65 (d, J=0.8 Hz, 3H), 2.06-2.2 (m, 2H).

1. filtrationwas filtered
2. concentrationconcentrated in vacuo
3. washwashed three times with heptane
4. customPurification via silica gel chromatography (Gradient: 20% to 50% ethyl acetate in heptane)