反应详情

A 12 L, 4-necked round bottom flask, equipped with a mechanical stirrer, 500 mL addition funnel, nitrogen inlet, and thermometer, was charged with 4515 mL of THF and 330.0 g of (4S,5R)-3-((2R,3R)-2,3-dimethyl-hexanoyl)-4,5-diphenyl-oxazolidin-2-one. The resulting liquid mixture (all solids dissolved) was cooled to −5° C. to 0° C. using an acetone/ice bath. A solution of 60.6 g of LiOH—H2O in 1800 mL of deionized water was cooled to 0° C. to 5° C. and was combined with 512 g of cold 30% (wt/wt) hydrogen peroxide in a 2 L Erlenmeyer flask. The solution was kept cold using an ice/water bath. After the oxazolidinone/THF solution in the 12 L reaction flask reached −5° C. to 0° C., the addition funnel was charged with approximately one quarter of the cold LiOH/water/H2O2 solution. While maintaining a nitrogen sweep to minimize oxygen concentration in the reactor headspace, the LiOH/water/H2O2 solution was added dropwise to the vigorously stirred oxazolidinone/THF solution at such a rate as to maintain the reaction temp at 0° C. to 5° C. The addition funnel was recharged with approximately one quarter of the cold LiOH/water/H2O2 solution as required until all of the solution had been added to the reaction mixture (about 40 minutes for 0.45 mol scale). After the addition was completed, the mixture was stirred at 0° C. to 5° C. for 5 hours, during which the reaction mixture changed from a homogeneous solution to white slurry. A solution of 341 g of Na2SO3 and 188 g of NaHSO3 in 2998 mL of deionized water (15 wt %) was added dropwise to the reaction mixture over about a 1.5 hour period (reaction was exothermic) via the addition funnel, while maintaining the reaction temperature at 0° C. to 10° C. Following the addition, the reaction mixture was stirred at 0° C. to 10° C. for 1 hour. The reaction mixture was tested with potassium iodide-starch test paper to ensure the absence of peroxides. The reaction mixture was charged with 2000 mL of EtOAc and was stirred 5 minutes. The phases were separated and the aqueous phase was extracted with 2000 mL of EtOAc. The combined organic extract was washed with brine (2×1500 mL). The colorless organic solution was concentrated under vacuum (35° C.-40° C.) to a “wet,” white solid. Heptane (1000 mL) was added and the slurry was concentrated under vacuum (35° C.-40° C.) to a wet, white solid. Heptane (5000 mL) was added and the slurry was maintained at 0° C. to 5° C. for 16 hours and then at −10° C. to −5° C. for 1 hour. The cold slurry was filtered through a thin pad of celite, and the filter cake was washed with 100 mL of −10° C. to −5° C. heptane. The colorless filtrate was concentrated under vacuum (40° C.-45° C.) to give 130 g of the titled compound as a pale yellow oil: 1H NMR (400 MHz, CHLOROFORM-D) 0.89 (t, J=7.00 Hz, 3H), 0.94 (d, J=6.8 Hz, 3H), 1.13 (d, J=7.0 Hz, 3H), 1.75-1.82 (m, 1H), 2.34-2.41 (m, 1H); GC Chiral purity: 99.18% (with 0.82% diastereomer) (direct acid method). Chemical purity: 100%. Anal. Calc'd for C8H16O2: C, 66.63; H, 11.18. Found: C, 66.15; H, 11.41.

1. customA 12 L, 4-necked round bottom flask, equipped with a mechanical stirrer, 500 mL addition funnel, nitrogen inlet
2. dissolutionThe resulting liquid mixture (all solids dissolved)
3. temperaturewas cooled to −5° C. to 0° C.
4. customreached −5° C. to 0° C.
5. temperatureWhile maintaining a nitrogen sweep
6. concentrationoxygen concentration in the reactor headspace
7. additionthe LiOH/water/H2O2 solution was added dropwise to the vigorously stirred oxazolidinone/THF solution at such a rate as
8. temperatureto maintain the reaction temp at 0° C. to 5° C
9. additionhad been added to the reaction mixture (about 40 minutes for 0.45 mol scale)
10. additionAfter the addition
11. additionA solution of 341 g of Na2SO3 and 188 g of NaHSO3 in 2998 mL of deionized water (15 wt %) was added dropwise to the reaction mixture over about a 1.5 hour period (reaction was exothermic) via the addition funnel
12. temperaturewhile maintaining the reaction temperature at 0° C. to 10° C
13. additionthe addition
14. stirringthe reaction mixture was stirred at 0° C. to 10° C. for 1 hour
15. additionThe reaction mixture was charged with 2000 mL of EtOAc
16. stirringwas stirred 5 minutes
17. customThe phases were separated
18. extractionthe aqueous phase was extracted with 2000 mL of EtOAc
19. extractionThe combined organic extract
20. washwas washed with brine (2×1500 mL)
21. concentrationThe colorless organic solution was concentrated under vacuum (35° C.-40° C.) to a “wet
22. additionHeptane (1000 mL) was added
23. concentrationthe slurry was concentrated under vacuum (35° C.-40° C.) to a wet, white solid
24. additionHeptane (5000 mL) was added
25. temperaturethe slurry was maintained at 0° C. to 5° C. for 16 hours
26. waitat −10° C. to −5° C. for 1 hour
27. filtrationThe cold slurry was filtered through a thin pad of celite
28. washthe filter cake was washed with 100 mL of −10° C. to −5° C. heptane
29. concentrationThe colorless filtrate was concentrated under vacuum (40° C.-45° C.)