287193-07-1

287193-06-0

287193-07-1

Ethyl 4-oxo-3,4-dihydro-2H-pyran-2-carboxylate (2.0 g, 11.75 mmol, 1.00 eq.) was dissolved in ethyl acetate (50 mL) in a 100 mL round-bottom flask under nitrogen atmosphere. 10% palladium/activated carbon (200 mg) was subsequently added. The system was degassed by three evacuation-nitrogen filling cycles. The reaction mixture was stirred at room temperature for 12 hours. Upon completion of the reaction, the solid catalyst was removed by filtration and the filter cake was washed with ethyl acetate (3×). The combined filtrates were concentrated under reduced pressure and the resulting crude product was purified by silica gel column chromatography with ethyl acetate/petroleum ether (1:20) as eluent to afford ethyl 4-oxotetrahydro-2H-pyran-2-carboxylate (1.62 g, 80% yield) as a light yellow oil.