Pinacol → 5-(Tetramethyl-1,3,2-dioxaborolan-2-yl)-2-(tris(propan-2-yl)silyl)-1,3-oxazole

HRID 930999Notes

Reaction equation

HRID 930999 reaction equation
[CH:1]([Si:4]([CH:13]([CH3:15])[CH3:14])([CH:10]([CH3:12])[CH3:11])[C:5]1[O:6][CH:7]=[CH:8][N:9]=1)([CH3:3])[CH3:2].CCCCCC.C([Li])CCC.C(O[B:31]([O:36][CH:37]([CH3:39])[CH3:38])[O:32][CH:33]([CH3:35])[CH3:34])(C)C.CC(O)(C(C)(O)C)C>C1COCC1.C(O)(=O)C>[CH3:39][C:37]1([CH3:38])[C:33]([CH3:34])([CH3:35])[O:32][B:31]([C:7]2[O:6][C:5]([Si:4]([CH:1]([CH3:3])[CH3:2])([CH:10]([CH3:12])[CH3:11])[CH:13]([CH3:15])[CH3:14])=[N:9][CH:8]=2)[O:36]1

Participants

7

Reactant 4

HCID 6425PinacolHCID 21531Triisopropyl borateHCID 595960162-(Tris(propan-2-yl)silyl)-1,3-oxazoleHCID 178418244HCID 178418244, compound

Product 1

HCID 442243115-(Tetramethyl-1,3,2-dioxaborolan-2-yl)-2-(tris(propan-2-yl)silyl)-1,3-oxazole

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-78 °C

Procedure

To a solution of 2-(triisopropylsilyl)oxazole (6.7 g) in THF (200 mL) was added dropwise n-butyllithium hexane solution (1.6M, 22.3 mL) at −78° C. The reaction mixture was stirred at −78° C. for 1 hr under nitrogen atmosphere, triisopropylborate (8.2 mL) was added thereto, and mixture was stirred at −78° C. for 2 hr. The mixture was allowed to be warmed to room temperature, and stirred overnight. To the reaction mixture was added a solution of 2,3-dimethylbutane-2,3-diol (3.51 g) in THF (20 mL) and acetic acid (2.3 mL), and the mixture was stirred at room temperature for 2 hr. The solvent was evaporated under reduced pressure, water was added thereto, and the mixture was extracted with ethyl acetate. The extract was washed with water and saturated brine, and dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/hexane) to give the title compound (8.8 g).

Workup

  1. stirringmixture was stirred at −78° C. for 2 hr
  2. temperatureto be warmed to room temperature
  3. stirringstirred overnight
  4. stirringthe mixture was stirred at room temperature for 2 hr
  5. customThe solvent was evaporated under reduced pressure, water
  6. additionwas added
  7. extractionthe mixture was extracted with ethyl acetate
  8. washThe extract was washed with water and saturated brine
  9. dry with materialdried over anhydrous sodium sulfate
  10. customthe solvent was evaporated under reduced pressure
  11. customThe residue was purified by silica gel column chromatography (ethyl acetate/hexane)

Sources & evidence

ORD record
ord-b638af84b0a24cf196b6d38f01b9c37d
Source dataset
uspto-grants-2016_03
Patent number
US09296746B2

Reaction notes

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