反应详情

Osmium tetraoxide (1 wt % in THF, 20.3 mL) is added to a mixture of (4R)-4-(triethylsilyloxy)-5-methyl-6-(2-methylthiazol-4-yl)-1,5-hexadiene (13.5 g), H2O (21 mL), and N-methylmorpholine N-oxide (50% in THF, 10 mL, 0.048 mol) in tert-butanol (155 mL) at 0° C. After the resulting mixture is stirred for 12 hours, Na2SO3 (10 g) and water (5 mL) are added. The resulting solution is stirred at 25° C. for 30 minutes and then extracted with ether. The combined extracts are washed with brine, dried (Na2SO4), filtered, and concentrated. Purification by flash chromatography on SiO2 provides a 1:1 diastereomeric mixture of the diol as a colorless, viscous oil. Lead tetraacetate (19.1 g) is added portionwise over 5 minutes to a suspension of the diol (18.0 g) and Na2CO3 (8.67 g) in 500 mL of benzene at 0° C. After stirring for 15 minutes, the mixture is filtered through a SiO2 pad to afford the aldehyde product. The product is directly subjected to the next reaction.

1. stirringThe resulting solution is stirred at 25° C. for 30 minutes
2. extractionextracted with ether
3. washThe combined extracts are washed with brine
4. dry with materialdried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated
7. customPurification by flash chromatography on SiO2
8. customprovides
9. stirringAfter stirring for 15 minutes
10. filtrationthe mixture is filtered through a SiO2 pad