Lithium tri-s-butylborohydride → HCID 15236679, compound

HRID 1975056Notes

Reaction equation

HRID 1975056 reaction equation
C([O:7][CH2:8][C:9]1[O:13][N:12]=[C:11]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][C:15]=2[C:20]2[N:21]=[N:22][N:23]([C:25]([C:38]3[CH:43]=[CH:42][CH:41]=[CH:40][CH:39]=3)([C:32]3[CH:37]=[CH:36][CH:35]=[CH:34][CH:33]=3)[C:26]3[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=3)[N:24]=2)[CH:10]=1)(=O)C(C)(C)C.CCC(C)[BH-](C(C)CC)C(C)CC.[Li+]>C1COCC1>[C:25]([N:23]1[N:22]=[N:21][C:20]([C:15]2[CH:16]=[CH:17][CH:18]=[CH:19][C:14]=2[C:11]2[CH:10]=[C:9]([CH2:8][OH:7])[O:13][N:12]=2)=[N:24]1)([C:32]1[CH:33]=[CH:34][CH:35]=[CH:36][CH:37]=1)([C:38]1[CH:43]=[CH:42][CH:41]=[CH:40][CH:39]=1)[C:26]1[CH:27]=[CH:28][CH:29]=[CH:30][CH:31]=1

Participants

4

Reactant 2

HCID 3611392Lithium tri-s-butylborohydrideHCID 15236678HCID 15236678, compound

Product 1

HCID 15236679HCID 15236679, compoundYield 84.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-20 °C

Procedure

A 100 ml round-bottom flask, equipped with a magnetic stirring bar, septum, and nitrogen inlet, was charged with 348 mg (0.61 mmol, 1.0 equiv) of the starting pivaloate (from Step O) and 8 ml THF (over sieves). The system was cooled down to -20° C. 1.35 ml (1.0M solution in THF, 1.34 mmol, 2.2 equiv) L-Selectride solution was added dropwise into the solution. The reaction was moved to a -20° C. freezer, kept for 18 hours, and then quenched with a basic peroxide solution, containing 25% saturated aqueous sodium bicarbonate solution, 50% methanol, and 25% of the 30% H2O2 in H2O solution. The resultant mixture was warmed to 0° C. and stirred for half an hour. Ethyl acetate was added to create two phases. The organic layer was separated from the aqueous one, which was extracted with 5×10 ml ethyl acetate. The combined organic portion was washed with 2×20 ml saturated aqueous sodium bicarbonate solution, dried over anhydrous sodium sulfate, filtered, concentrated, and chromatographed on a silica gel column (3 cm ×26 cm, 3:2=hexane:ethyl acetate, with 1% distilled triethylamine) to afford 250 mg of the desired product in 84% yield: Rf=0.15 (3:2=hexane:ethyl acetate, with 1% distilled triethylamine); 1H NMR δ5.87 (s, HC on the isoxazole ring), 4.41 (s, CH2OH); 13C NMR δ103.3 (HC on the isoxazole ring), 83.2 (C(C6H5)3), 56.3 (CH2OH).

Workup

  1. customA 100 ml round-bottom flask, equipped with a magnetic stirring bar
  2. customwas moved to a -20° C.
  3. customquenched with a basic peroxide solution
  4. additioncontaining 25% saturated aqueous sodium bicarbonate solution, 50% methanol, and 25% of the 30% H2O2 in H2O solution
  5. temperatureThe resultant mixture was warmed to 0° C.
  6. additionEthyl acetate was added
  7. customThe organic layer was separated from the aqueous one, which
  8. extractionwas extracted with 5×10 ml ethyl acetate
  9. washThe combined organic portion was washed with 2×20 ml saturated aqueous sodium bicarbonate solution
  10. dry with materialdried over anhydrous sodium sulfate
  11. filtrationfiltered
  12. concentrationconcentrated
  13. distillationchromatographed on a silica gel column (3 cm ×26 cm, 3:2=hexane:ethyl acetate, with 1% distilled triethylamine)

Sources & evidence

ORD record
ord-9684f8a6911b49328ce07101cef5f917
Source dataset
uspto-grants-1994_02
Patent number
US05284841

Reaction notes

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