反应详情

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 SM. An aliquot was taken and dissolved in CDCl3 to run 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 get a liquid. The liquid was subject a reduced distillation 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.

1. custommilky cloudy product was formed
2. waitwas continued for 4 h
3. dissolutiondissolved in CDCl3
4. customThe two layers were separated
5. extractionthe aqueous layer was extracted with EtOAc (5×50 mL)
6. additionMore water was added
7. dissolutionto dissolve the solid
8. customresulting in a clear solution
9. washThe combined extracts were washed with brine
10. concentrationconcentrated to dryness
11. customto get a liquid
12. distillationa reduced distillation
13. customto remove isopropanol
14. customThe remaining liquid was purified on a 50-g silica gel column
15. washeluted with 50% EtOAc in Heptane
16. customThe product fractions were collected
17. concentrationconcentrated