Oxalic Acid → 3-(Tetrahydro-2H-pyran-2-yl)-acrolein

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Reaction Steps

A solution of (tetrahydro-2H-pyran-2-yl)carboxaldehyde (1 molar equivalent) in ether is added to a cold (-70° C.), rapidly-stirred solution of the freshly-generated lithium salt of ethylidenecyclohexylamine (1 molar equivalent) in ether. The resulting reaction mixture is allowed to warm to room temperature, then is maintained at room temperature for 24 hours. After cooling to 0° to 5° C., the reaction mixture is diluted with water, stirred at 0° to 5° C. for 1/2 hour and evaporated in vacuo at 40° to 50° C. leaving a residual oil which is treated with oxalic acid (2 molar equivalents) and water. Steam distillation of this mixture is continued until a clear distillate is obtained. The steam distillate is extracted with ether and the organic extract, dried over sodium sulfate, and filtered. Evaporation of the filtrate in vacuo at 40° C. provides the title compound as a mobile oil.

Provenance & Evidence