反应详情

Potassium tetrahydroxydioxidoosmium (0.041 g, 0.111 mmol) was added to a solution of 1-tert-butyl 4-ethyl 4-(2-methylenebutyl)piperidine-1,4-dicarboxylate (1.0 g, 3.07 mmol) in acetone (20 mL) and water (20 mL) and stirred for 10 min. Solid sodium periodate (2.62 g, 12.26 mmol) was added in four portions during 1 hour and the reaction temperature was maintained below 40° C. using an ice-bath. The resulting mixture was stirred for 1 hour at room temperature. At this point LCMS showed incomplete reaction. Another 0.036 eq. of potassium tetrahydroxydioxidoosmium (0.041 g, 0.111 mmol) was added and the mixture was then stirred at rt for 2 hours. LCMS after 2 hours showed completion of the reaction. The suspension was filtered and filtrate was concentrated to remove acetone, and the aqueous layer was extracted with DCM (15 mL×3). The combined organic layers were washed with 10% Na2S2O3 solution (20 ml×2), dried over anhydrous Na2SO4, filtered, then concentrated to get the crude product which was purified by silica gel column chromatography (80 g RediSep Gold column) using (0-35) % EtOAc/Hexanes as mobile phase and the title compound was isolated.

1. temperaturethe reaction temperature was maintained below 40° C.
2. stirringThe resulting mixture was stirred for 1 hour at room temperature
3. customreaction
4. stirringthe mixture was then stirred at rt for 2 hours
5. waitLCMS after 2 hours showed
6. customcompletion of the reaction
7. filtrationThe suspension was filtered
8. concentrationfiltrate was concentrated
9. customto remove acetone
10. extractionthe aqueous layer was extracted with DCM (15 mL×3)
11. washThe combined organic layers were washed with 10% Na2S2O3 solution (20 ml×2)
12. dry with materialdried over anhydrous Na2SO4
13. filtrationfiltered
14. concentrationconcentrated
15. customto get the crude product which
16. customwas purified by silica gel column chromatography (80 g RediSep Gold column)