Boron tribromide → 7-Bromomethyl-5-methoxy-2-(4-methoxy-phenyl)-benzofuran

HRID 1794477Notes

Reaction equation

HRID 1794477 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH2:20]O)[C:6]2[O:10][C:9]([C:11]3[CH:16]=[CH:15][C:14]([O:17][CH3:18])=[CH:13][CH:12]=3)=[CH:8][C:7]=2[CH:19]=1.B(Br)(Br)[Br:23]>ClCCl>[Br:23][CH2:20][C:5]1[C:6]2[O:10][C:9]([C:11]3[CH:16]=[CH:15][C:14]([O:17][CH3:18])=[CH:13][CH:12]=3)=[CH:8][C:7]=2[CH:19]=[C:3]([O:2][CH3:1])[CH:4]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 10192985HCID 10192985, compound

Product 1

HCID 102867967-Bromomethyl-5-methoxy-2-(4-methoxy-phenyl)-benzofuran

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
-78 °C

Procedure

Benzyl Alcohol 3 (1.02 g, 3.59 mmole) was dissolved in dichloromethane (70 mL) and cooled to −78° C. in an dry ice/acetone bath. Boron tribromide (1.0 M in dichloromethane), (3.95 mL, 3.95 mmole) was added drop wise over 15 minutes. After 30 minutes, the light orange solution was allowed to come to room temperature and reacted for an additional four hours. The solution was concentrated and added to saturated sodium bicarbonate, and extracted with ethyl acetate. Organic layers were combined and washed with water and brine, dried over magnesium sulfate. The organic phases were concentrated and the residue was loaded on to silica gel and chromatographed with silica gel (hexanes:ethyl acetate, 9:1) to afford 2.91 g (81%) of benzyl bromide17 as a white solid: Mp=158–160° C.; 1H NMR (DMSO-6) δ 7.88(d, 2 H, J=8.8 Hz), 7.23 (s, 1 H), 7.11 (d, 2 H, J=2.5 Hz), 7.09 (d, 2 H, J=8.9 Hz), 6.99 (d, 1 H, J=2.5 Hz), 4.96 (s, 2 H), 3.82 (s, 3 H), 3.80 (s, 3 H).

Workup

  1. customto come to room temperature
  2. customreacted for an additional four hours
  3. concentrationThe solution was concentrated
  4. additionadded to saturated sodium bicarbonate
  5. extractionextracted with ethyl acetate
  6. washwashed with water and brine
  7. dry with materialdried over magnesium sulfate
  8. concentrationThe organic phases were concentrated
  9. customchromatographed with silica gel (hexanes:ethyl acetate, 9:1)
  10. customto afford 2.91 g (81%) of benzyl bromide17 as a white solid

Sources & evidence

ORD record
ord-01dbdc62e7224b0d89d4f20162a2637c
Source dataset
uspto-grants-2006_04
Patent number
US07022733B2

Reaction notes

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