Trifluoroacetic acid → 2,4,6-Tri-tert-butyl-5-hydroxy-2,3-dihydrobenzofuran

HRID 1900488Notes

Reaction equation

HRID 1900488 reaction equation
C([SiH](CC)CC)C.[C:8]([C:12]1[O:13][C:14]2[CH:20]=[C:19]([C:21]([CH3:24])([CH3:23])[CH3:22])[C:18]([OH:25])=[C:17]([C:26]([CH3:29])([CH3:28])[CH3:27])[C:15]=2[CH:16]=1)([CH3:11])([CH3:10])[CH3:9].FC(F)(F)C(O)=O.[OH-].[Na+]>>[C:8]([CH:12]1[CH2:16][C:15]2[C:17]([C:26]([CH3:29])([CH3:28])[CH3:27])=[C:18]([OH:25])[C:19]([C:21]([CH3:24])([CH3:23])[CH3:22])=[CH:20][C:14]=2[O:13]1)([CH3:11])([CH3:9])[CH3:10]

Participants

5

Reactant 4

HCID 6422Trifluoroacetic acidHCID 12052TriethylsilaneHCID 14798Sodium HydroxideHCID 118228042,4,6-Tri-tert-butyl-5-hydroxybenzofuran

Product 1

HCID 110775842,4,6-Tri-tert-butyl-5-hydroxy-2,3-dihydrobenzofuranYield 76.1%

Conditions

Temperature
0 °C

Procedure

Triethylsilane (76 ml) was added to 2,4,6-tri-tert-butyl-5-hydroxybenzofuran (24.7 g, 82 mmol) and trifluoroacetic acid (38 ml) was added dropwise to the mixture under ice cooling. The mixture was stirred first at 0° C. for 15 min, then at room temperature for 15 min before it was poured into ice water. The mixture was neutralized with an aqueous solution of 1N sodium hydroxide and subjected to extraction with ethyl acetate. The extracted layer was washed with a saturated aqueous solution of sodium hydrogen carbonate, dried over anhydrous magnesium sulfate and concentrated. The concentrate was purified by silica gel chromatography (chloroform) to afford 2,4,6-tri-tert-butyl-5-hydroxy-2,3-dihydrobenzofuran [19.0 g (yield, 76%)].

Workup

  1. additionwas added dropwise to the mixture under ice cooling
  2. extractionsubjected to extraction with ethyl acetate
  3. washThe extracted layer was washed with a saturated aqueous solution of sodium hydrogen carbonate
  4. dry with materialdried over anhydrous magnesium sulfate
  5. concentrationconcentrated
  6. customThe concentrate was purified by silica gel chromatography (chloroform)

Sources & evidence

ORD record
ord-8e7ba418b6544c0f8d43bb33e7a0036b
Source dataset
uspto-grants-1996_11
Patent number
US05574178

Reaction notes

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