Water → Ethyl 4-oxo-3,4-dihydro-2H-pyran-2-carboxylate

A solution of ZnCl (0.63 g, 4.6 mmol) in anhydrous THF (15 mL) was added to a solution of 1-methoxy-3-(trimethylsilyloxy)-1,3-butadiene (7.94 g, 46.0 mmol) and ethyl glyoxalate (7.05 g, 69.0 mmol) in toluene (30 mL) at room temperature. After stirring for 30 minutes, water (30 mL) and TFA (2 mL) were added, and the mixture was stirred vigorously for 20 minutes. After concentration, the residue was partitioned between EtOAc (200 mL) and water (100 mL). The separated organic layer was washed with brine, dried over sodium sulfate, and concentrated to give 4-oxo-3,4-dihydro-2H-pyran-2-carboxylic acid ethyl ester (8.0 g, 100% yield) as an oil, which was carried to the next step without further purification. 1H NMR (500 MHz, CDCl3) δ 7.40 (d, J=1.0 Hz, 1H), 5.48 (d, J=6.5 Hz, 1H), 5.02 (t, J=8.0 Hz, 1H), 4.26 (q, J=7.0 Hz, 2H), 2.85 (d, J=8.0 Hz, 2H), 1.32 (t, J=7.5 Hz 3H); LCMS (ESI) m/z: 171 [M+H]+.

1. stirringthe mixture was stirred vigorously for 20 minutes
2. concentrationAfter concentration
3. customthe residue was partitioned between EtOAc (200 mL) and water (100 mL)
4. washThe separated organic layer was washed with brine
5. dry with materialdried over sodium sulfate
6. concentrationconcentrated

ORD record

ord-3673393cd909473d9398f7d252d597c1

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09259470B2