Chlorotrimethylsilane → 7-Bromo-2-(trimethylsilyl)benzofuran

HRID 2355397Notes

Reaction equation

HRID 2355397 reaction equation
C(NC(C)C)(C)C.[Li]CCCC.Cl[Si:14]([CH3:17])([CH3:16])[CH3:15].[Br:18][C:19]1[C:27]2[O:26][CH:25]=[CH:24][C:23]=2[CH:22]=[CH:21][CH:20]=1.[NH4+].[Cl-]>C1COCC1.Cl>[Br:18][C:19]1[C:27]2[O:26][C:25]([Si:14]([CH3:17])([CH3:16])[CH3:15])=[CH:24][C:23]=2[CH:22]=[CH:21][CH:20]=1

Participants

8

Reactant 5

HCID 6397ChlorotrimethylsilaneHCID 7912DiisopropylamineHCID 25517Ammonium ChlorideHCID 1136287-Bromo-1-benzofuranHCID 178418339Butyllithium

Product 1

HCID 179295107-Bromo-2-(trimethylsilyl)benzofuranYield 98%

Reagents, catalysts & solvents 2

HCID 313Hydrochloric AcidSolventHCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
5 °C

Procedure

A stirred solution of diisopropylamine (0.65 mL, 4.7 mmol) in THF (15 L) was cooled to 5° C. and n-BuLi (2.5 M in hexanes, 1.9 mL, 4.7 mmol) was added dropwise over 5 min. The mixture was stirred at 5° C. for 15 min and cooled to −70° C. Chlorotrimethylsilane (0.59 mL, 4.7 mmol) was added followed by a solution of 7-bromobenzofuran (0.46 g, 2.35 mmol) in THF (5 mL). The mixture was stirred at −70° C. for 1.5 h and poured into sat'd aq NH4Cl (80 mL). The mixture was diluted with 5% aq HCl (20 mL) and extracted with ether (2×80 mL). The combined ether extracts were washed with sat'd aq NaHCO3 (50 mL), dried over MgSO4 and concentrated to leave crude 7-bromo-2-(trimethylsilyl)benzofuran (0.62 g, 98%) as a yellow oil.

Workup

  1. temperaturecooled to −70° C
  2. stirringThe mixture was stirred at −70° C. for 1.5 h
  3. extractionextracted with ether (2×80 mL)
  4. washThe combined ether extracts were washed with sat'd aq NaHCO3 (50 mL)
  5. dry with materialdried over MgSO4
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-c02bca6c082441ab8b502a515395f564
Source dataset
uspto-grants-2010_07
Patent number
US07754737B2

Reaction notes

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