Methanol → 4-(3-Oxo-propyl)tetrahydro-pyran-4-carboxylic acid methyl ester

Beteiligte Stoffe

Reaktionsschritte

4-But-3-enyl-tetrahydro-pyran-4-carboxylic acid methyl ester (6 g, 30 mmol) was dissolved in iPrOH (150 mL). To this was added a aqueous solution of NaIO4 (14 g, 65.2 mmol, 2.18 equiv.) in water (150 mL), followed by addition of OsO4 (25 mg, crystals, in one portion) at rt. The solution was stirred with a mechanical stirrer at rt (water bath). After 30 min, milky cloudy product was formed. Stirring was continued for 4 h. TLC (1% MeOH in DCM, and 5% MeOH in DCM) did not detect the starting material. An aliquot was taken and dissolved in CDCl3 to run 1H NMR, there was no alkene peak in the sample. The reaction was judged to be complete. The reaction mixture was poured into ice water (200 mL) and EtOAc (200 mL). The two layers were separated and the aqueous layer was extracted with EtOAc (5×50 mL). More water was added to dissolve the solid resulting in a clear solution. The combined extracts were washed with brine, and concentrated to dryness to obtain a liquid product. The liquid product was subject to a distillation under reduced pressure to remove isopropanol. The remaining liquid was purified on a 50 g silica gel column, eluted with 50% EtOAc in Heptane. Note: the product is not UV active. Anisaldehyde visualization was used. The product fractions were collected and concentrated to yield 5.62 g (94% yield) of the title compound as a liquid.

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