反应详情

Methyl 4-oxo-tetrahydro-2H-pyran-3-carboxylate and methyl 4-hydroxy-5,6-dihydro-2H-pyran-3-carboxylate (13.5 g, 85.5 mmol) were dissolved in DMF (70 mL). Sodium hydride (60%, 3.6 g, 1.05 eq) was added at 0° C. After 10 min, iodomethane (6.7 mL, 1.25 eq) was added. The reaction was stirred overnight, diluted with ethyl acetate (200 mL), and washed with water (5×100 mL). The aqueous layer was re-extracted with ethyl acetate. The combined organic layers were washed with brine, dried over MgSO4, and concentrated. The residue was purified by chromatography on silica gel eluting with 20% ethyl acetate/hexane to yield 8.2 g (61%) of methyl 3-methyl-4-oxo-tetrahydro-2H-pyran-3-carboxylate.

1. washwashed with water (5×100 mL)
2. extractionThe aqueous layer was re-extracted with ethyl acetate
3. washThe combined organic layers were washed with brine
4. dry with materialdried over MgSO4
5. concentrationconcentrated
6. customThe residue was purified by chromatography on silica gel eluting with 20% ethyl acetate/hexane