反应详情

A solution of methyl 6-hydroxy-(Z)-3-hexenoate (0.7684 g, 5.3 mmol), 3,4-dihydropyran (0.72 mL, 7.9 mmol, 1.5 eq) and pyridinium p-toluenesulfonate (PPTS, 125 mg, 0.5 mmol) in methylene chloride (25 mL) is stirred for 4 hours at room temperature. The solution is then diluted with ether (150 mL), and the ether layer is washed with half-saturated brine (50 mL) to remove the catalyst, and dried over magnesium sulfate. Purification by flash chromatography using hexane/ethyl acetate (90:10, v/v) affords methyl 6-tetrahydropyranyloxy-(Z)-3-hexenoate (1.19 g, 99%) as a clear colorless oil: Rf=0.38, hexane/ethyl acetate (7:3, v/v), IR (film) ν2850-3000 (C=CH, alkane CH), 1740 (C=O) and H NMR (CDCl3) δ1.45-1.65 (m, 6H), 2.35 (m, 2H), 3.10 (d, J=6 Hz, 2H), 3.30-3.70 (m, 4H), 3.58 (sS, 3H), 4.55 (br s, 1H), 5.65 (br t, J=6 Hz, 2H).

1. washthe ether layer is washed with half-saturated brine (50 mL)
2. customto remove the catalyst
3. dry with materialdried over magnesium sulfate
4. customPurification by flash chromatography