Trifluoroacetic acid → 5-Bromo-7-isopropyl-3,3,6-trimethyl-2,3-dihydro-benzofuran

HRID 2290149Notes

Reaction equation

HRID 2290149 reaction equation
[Br:1][C:2]1[C:3]([CH3:17])=[C:4]([C:13](O)([CH3:15])[CH3:14])[C:5]2[O:9][CH2:8][C:7]([CH3:11])([CH3:10])[C:6]=2[CH:12]=1.C([SiH](CC)CC)C.FC(F)(F)C(O)=O.C(=O)(O)[O-].[Na+]>ClCCl.O.CO>[Br:1][C:2]1[C:3]([CH3:17])=[C:4]([CH:13]([CH3:14])[CH3:15])[C:5]2[O:9][CH2:8][C:7]([CH3:10])([CH3:11])[C:6]=2[CH:12]=1

Participants

8

Reactant 4

HCID 6422Trifluoroacetic acidHCID 12052TriethylsilaneHCID 516892Sodium BicarbonateHCID 186991752-(5-Bromo-3,3,6-trimethyl-2,3-dihydro-benzofuran-7-yl)-propan-2-ol2×

Product 1

HCID 186991975-Bromo-7-isopropyl-3,3,6-trimethyl-2,3-dihydro-benzofuranYield 95.5%

Reagents, catalysts & solvents 3

HCID 887MethanolSolventHCID 962WaterSolventHCID 6344DichloromethaneSolvent

Procedure

A stirred, cooled (ice bath)solution of 2-(5-bromo-3,3,6-trimethyl-2,3-dihydro-benzofuran-7-yl)-propan-2-ol (Compound 49, 1.51 g, 5.03 mmol) in 15 mL of dichloromethane was treated with triethyl silane (1.4 mL, 8.76 mmol) followed by trifluoroacetic acid (0.65 mL, 8.43 mmol) and the resulting clear, colorless solution was stirred at ambient temperature overnight. The reaction mixture was cooled, treated with 6 mL each of methanol and water, neutralized cautiously with saturated sodium bicarbonate solution and extracted with diethylether. The organic extract was dried over anhydrous sodium sulfate, filtered and evaporated to an oil. Flash column chromatography using 0.5% ethyl acetate in hexanes as the eluent afforded the title compound (1.36 g, 95%) as an oil. 1H NMR (300 MHz, CDCl3): δ 7.11 (s, 1H), 4.18 (s, 2H), 3.25 (heptet, 1H, J=7.1 Hz), 2.40 (s, 3H), 1.30 (s, 6H), 1.31 (d, 6H, J=7.1 Hz).

Workup

  1. temperatureThe reaction mixture was cooled
  2. extractionextracted with diethylether
  3. extractionThe organic extract
  4. dry with materialwas dried over anhydrous sodium sulfate
  5. filtrationfiltered
  6. customevaporated to an oil

Sources & evidence

ORD record
ord-44bf681f6b134a7f9268fa6a72c31de1
Source dataset
uspto-grants-2000_07
Patent number
US06093838

Reaction notes

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