Diethyl Ether → 4-Hydroxy-6-methyl-2-pyrone

Reaction equation

[C:1]1(C(O[Si](C)(C)C)=C)[CH:6]=CC=C[CH:2]=1.[C:14](Cl)(=[O:19])[CH2:15][C:16](Cl)=[O:17].CC[O:23]CC>>[OH:19][C:14]1[CH:2]=[C:1]([CH3:6])[O:17][C:16](=[O:23])[CH:15]=1

Participants

Reactant 3

HCID 3283Diethyl Ether

HCID 74269Propanedioyl dichloride

HCID 117406Benzene, [1-[(trimethylsilyl)oxy]ethenyl]-

Product 1

HCID 546757574-Hydroxy-6-methyl-2-pyroneYield 67%

Procedure

A solution of 1-phenyl-1-trimethylsiloxyethylene (25.0 g, 130 mmol) in absolute ether (400 mL) was cooled to −78° C., and malonyl dichloride (6.40 mL, 65.0 mmol) was added dropwise to the resulting solution by using a dropping funnel. The mixture was gradually heated to room temperature, stirred at room temperature (5 to 10° C.) for 14 hours, and further stirred at 30° C. for 24 hours. The thus-produced yellow precipitate was filtered and washed with absolute ether to give the target 4-hydroxy-6-methyl-2-pyrone (8.40 g, 67%) as a yellow solid.