Borane → HCID 10903840, compound

HRID 636024Notes

Reaction equation

HRID 636024 reaction equation
CC(=C(C)C)C.B.[CH2:8]([O:15][C:16]([NH:18][C@@H:19]([C@H:27]([CH3:30])[CH:28]=[CH2:29])[C:20]([O:22][C:23]([CH3:26])([CH3:25])[CH3:24])=[O:21])=[O:17])[C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.C1C[O:34]CC1>>[CH2:8]([O:15][C:16]([NH:18][C@@H:19]([C@H:27]([CH3:30])[CH2:28][CH2:29][OH:34])[C:20]([O:22][C:23]([CH3:24])([CH3:25])[CH3:26])=[O:21])=[O:17])[C:9]1[CH:10]=[CH:11][CH:12]=[CH:13][CH:14]=1

Participants

5

Reactant 4

HCID 6331BoraneHCID 8028Tetrahydrofuran3×HCID 112502,3-Dimethyl-2-buteneHCID 10990791HCID 10990791, compound

Product 1

HCID 10903840HCID 10903840, compoundYield 89%

Conditions

Temperature
0 °C

Procedure

To a 0° C. solution of 2,3-dimethyl-2-butene in THF (43.2 mmol, 1.0 M) is added a solution of borane in THF (43.2 mmol, 1.0 M) dropwise over 20 min. After stirring an additional 60 min at 0° C., tert-butyl (2S,3R)-2-benzyloxycarbonylamino-3-methyl-4-pentenoate (13.15 g, 41.2 mmol) in 20 mL THF is added dropwise, and the resulting solution is allowed to come to 25° C. over 60 min. The solution is cooled again to 0° C. and quenched with 6 ml of 1:1 THF-ethanol, added cautiously, then 40 mL of pH 7.0 phosphate buffer. 40 mL 30% hydrogen peroxide is added and the reaction mixture is stirred at 25° C. for 14 h. The mixture is partially concentrated, added to saturated aqueous sodium chloride, and extracted with ether. The combined organic layers are washed twice with ice-cold saturated aqueous sodium sulfite, water, and saturated aqueous sodium chloride, and dried over magnesium sulfate. Concentration in vacuo and purification by silica gel chromatography (elution with hexanes-EtOAc, 3:2) provides tert-butyl (2S,3R)-2-benzyloxycarbonylamino-3-methyl-5-hydroxypentanoate as an oil (12.3 g, 89%).

Workup

  1. waitto come to 25° C. over 60 min
  2. temperatureThe solution is cooled again to 0° C.
  3. customquenched with 6 ml of 1:1 THF-ethanol
  4. additionadded cautiously
  5. addition40 mL 30% hydrogen peroxide is added
  6. stirringthe reaction mixture is stirred at 25° C. for 14 h
  7. concentrationThe mixture is partially concentrated
  8. additionadded to saturated aqueous sodium chloride
  9. extractionextracted with ether
  10. washThe combined organic layers are washed twice with ice-cold saturated aqueous sodium sulfite, water, and saturated aqueous sodium chloride
  11. dry with materialdried over magnesium sulfate
  12. concentrationConcentration
  13. customin vacuo and purification
  14. washby silica gel chromatography (elution with hexanes-EtOAc, 3:2)

Sources & evidence

ORD record
ord-38509009705c4efeb2539b9465614cbc
Source dataset
uspto-grants-2001_02
Patent number
US06191150B1

Reaction notes

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